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Agronomic Studies on the Genecological Different iat ion of soybeans inJapan and the World(日本及び世界における大豆品種の種生態学的分化に関する栽培、育種学的研究)

著者Author(s) Nagata, Tadao

掲載誌・巻号・ページCitat ion 兵庫農科大學研究報告. 農学編,4(2):96-122

刊行日Issue date 1960

資源タイプResource Type Departmental Bullet in Paper / 紀要論文

版区分Resource Version publisher

権利Rights

DOI

JaLCDOI 10.24546/81006586

URL http://www.lib.kobe-u.ac.jp/handle_kernel/81006586

PDF issue: 2020-07-24

AGRONOMIC STUDIES ON THE GENECOLOGICAL '

DIFFERENTIATION OF SOYBEANS IN

JAPAN AND THE WORLD

Tadao NAGATA

(Laboratory of Plant Breeding)

CONTENTS

Introduction

' I. Adaptation of the Summer vs. Autumn Soybean Types to the Planting .Time in Relation to the Flowering and the Fruiting.

1.' Flowerings and fruitings of the summer vs. autumn soybean types planted in a spaced rate and at the times of successive intervals throughout the growing season.

2. Effect · of the daylength after the flower pri· mordia initioti~n , on , the flowering process of the autumn soybean type in an ecological aspect of the planting time.

. II. Significance of the , Indeterminate Growth Habit in the Cultivation and Breeding of Soybeans. I. A~ronomic ~haracteristics of the soybeans having

,' thesaid habit.

3. Properties of American soybeans attributive . to their indeterminate growth habit.

4. A supposed reason for cultivating , the indeter· minate growing soybeans in the tropics.

5. Some ' genetic associations between the deter· .minate vs. indeterminate growth habit and other agronomic characters.

III. Significance of the Indeterminate Growth Habit in the Cultivation and Breeding of Soybeans. '.' II. Regional adaptabilities of the principal varieties of the summer soybean type cultivated in diffe' rent regions.

6. Cooperative performances in Japan • 7. Cooperative performances in the Uni~ed States

of America.

Summary and conclusion.

INTRODUCTION

As suggested already by the author (1960a), the' ecotypic differentiation of soybeans in Japan and in the world is a result of the agronomic adaptation as well as the ecological responses to the factors including the climate; soil, and other biotic competitions.

Consequently, it is of very much interest to consider the possible significance in the cultiva· tion and breeding of soybeans in reference to the results of genecological studies of the soybean dif· ferentiation by the author (NAGATA 1959, 1960a).

In the view from such an angle of the studies, many experiments have been carried out and the results are dealt' with in the paper.

The author wishes to express his sincere ,thanks to D~, N. ENOMOTO, Emeritus Professor of the Kyoto University and Dr. K. KAWAKAMI, ' Professor of our laboratory, who have encouraged the author and

96

given careful guidances in the courses of the studies. Sincere acknowledgements are also due to the following researchers who have given care' ful guidances or cooperative helps for the studies: Dr. M. G. WEISS and Dr. H. W. JOHNSON of the Crops Research Division, Agricultural Research Service, U. S. Dept. of Agriculture, Dr. J. L. CARTTER of the Regional Soybean Laboratory in Urbana, Illinois, Dr. E. E. HARTWIG of the Delta Branch Expt. Station in Stoneville, Mississippi, Mr. K. OZAKI of the Hokkaido Agr. Expt. Station and Mr. Y. FURu­TANI of the Kyushu Agr. Expt. Station.

Finally the author should like to note his heart­felt thanks to the kind ad vices and reading the manuscript by Dr. H. W. JOHNSON of the Agri· cultural Research Service, U. S. Dept. of Agriculture, and Professor H. HASEGAWA and Professor K. SHAKUDO of the Kyoto University.

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

1. ADAPTATION OF THE SUMMER VS. AUTUMN SOYBEAN

TYPES TO THE PLANTING. TIME IN RELATION TO

THE FLOWERING AND THE FRUITING

1. Flowerings and Fruitings of the Summer vs. Autumn Soybean

Types Planted in a Spaced Rate -and at the Times 6f

Successive Intervals Throughout the Growing Season -l-As mentioned in a previous report (NAGATA

1960a), the soybeans have the summer vs. autumn soybean types different in their responses to the planting time in Central and South China, and South Japan; the former is adaptable to the early time planting, viz. March to April, and the latter to the late time planting, viz. June to July.

In physiological and ecological aspects of such an adaptation of soybeans, many problems still remain obscure. The old literature in China, Lii'shi Chun-tsiu (B.C. 240-300), described with respect to the response of soybean to the planting time as follows: The soybean planted at the adaptable time became long in the stem, but each node was short and bearing more than 10 pods in a cluster; when planted before the adaptable time, the stem of soybeans became too long and vining with too many leaves and elongated internodes, and then pods were few on the nodes and abortive for the most part: in the late planting after the adaptable time, the stems of soYbeans became very short and less in the node, and then - no seed was pro­duced.

Recently, GARNER and ALLARD (1920) found the photoperiodic responses of plants first, and late flowering soybeans were pointed out as high sensi­tive plants to the short day length, Hence, when planted early, the soybeans of the autumn soybean types are delayed in the flowering under the com­paratively long days of the natural phenological conditions, and as a consequence of the delay, the plants grew vegetatively during the long period and produced many branches and leaves exces­sively.

In general, many farmers and agronomists in Japan have considered that such an excess vegeta­tive growth caused the poor seed yields of the said soybeans planted early, as mentioned in Lii­shi Chun-tsiu cited above.

The author has carried out many experiments on the behavior of the summer vs. autumn soy­bean types with respect to the adaptation to the planting time, and the effect of the daylength after the flower primordia initiation was found to

97

be a unique part of photoperiodism affecting the yield of soybeans planted at successive times.

The better understanding on the effect of the planting time on the flowering and fruiting of the summer vs. autumn soybean types, when planted in adequately wide spacing, is afforded herein, for the yield of soybeans without the effect of spacing is of primary _ importance in order to consider the physiological aspect of the subject carefully.

Materials and Methods. The experiments which were carried out- in the Hyogo University of Agriculture, Sasayama, Hyogo, in 1951, consisted of two parts:-

i. Three representative varieties, namely, Aoji of the summer soybean type, Mejiro No. 1 of the intermidiate type, and _ Akazaya Shirodaizu of the autumn soybean type were planted at successive times :throtghout the growing season. The first date of planting was April 10, and the last of planting was July 25, and the total number of plantings was eight at successive half month inter­vals.

ii. Eighteen representatives of the summer vs. autumn soybean types, as shown in fig. 6 and 8, were ;planted at two times, namely May 5 and June 25.

The soybeans in each plot were planted in rows 90-cm wide and the plants on row were thinned out in the same 90-cm intervals as _ the row width, and then a plant was ploted per gO-cm square. Such an area, in general, was adequate for the vegetative growth of the autumn soybean type planted very early.

Yields and Yield Components

The yields of three materials behaved to cor: respond to the times of planting, as shown in fig. 1. The highest yield of Aoji of the summer soy­bean type was obtained when planted -in April, whereas the autumn soybean type, Akazaya Shiro­daizu did not increase the yields in such an early planting and gave rise to fair yields when planted in, the latter part of May to June. Akazaya Shiro-

XII, 1950 Series: Agriculture

350 50.0 f'

~ ~ 47. , (;120 .. o

g h5 ·0 0

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DATE OP PLANTING --+ -' - . AOJI(SUMMER) . o • MEJIRO NO.1 ( INTERllEDIAT3)

- -0 AKAZAYA. SHIROOAlZU(AUTUY .. N)

FIG. 1. Seed yields of the representative varieties of the summer vs. autumn soybean types, as affected by the planting time.

daizu soybean grew into an excessively gross plant in the early plantings, and then the seed yields were rather less as compared with the growth of plants and leaves (fig. 1). The intermediate type, Mejiro No. 1 was intermediate in the variation of the yields due to planting t imes.

As the yield compositional factors influencing the seed yields in the experiment, the number of flowers per plant. the percentage of pods to flowers and the seed sizes shown by 1()()·seed weight were measured and considered in the relation of those characters to the seed yields.

The number of flowers per plant in each plant­ing time showed the parallel variation to the seed yields in each of three materials. While the per­centage of pods to flowers. and seed size did not correlate to the seed yields in each planting time (fig. 3) .

The varietal difference in the change of flower­ing due to the planting times was the most apparent in the number of flowers per node, viz. the ratio of total flowers per node. The flowers per node of the autumn soybean type were the most abundant when planted in June, when the planting was practically going on the central and south parts of Japan, whereas the other two types were definitely less in the flowers per node than the autumn soy· bean type when planted at the same times (fig. 4) .

Results of the experiment using eighteen soy· beans presented more clearly the varietal differ· ences with respect to the above characters. In the results, the rat io of the seed weight to the total plant weight showed the opposite trend between

98

Aoji (summer soybean type)

Mejiro No. 2 (intermediate type)

Akazaya Shirodaizu (autumn soybean type)

FIG. 2. Growths of the representatives of the summer vs. autumn soybean types planted at half month intervals from April 15 (I) to July 25 (VIII ).

the summer and the autumn soybean types in rela­tion to the planting time, though the seed yield

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

700 0 0 '--. AOJI

~ 600 0 0 CIl .... - -. HEJIRO NO . 1 '" 0-1 ~100 ~ ... 500 ~ AKAZAYA

III &"! SHIRODAIZl1 ~

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DArB OF PLANTING

FIG. 3. Flowerings and fruitings of the representatives of the summer vs. autumn soybean types planted at successive times.

7

§ 6

:z; 5

~ 4

~ , o &"! 2

o

1~~~~~~~~ __ ~-L-4/10 25 5/10 25 6/10 25 7/10 25.

DATE OF PLANTING

FIG. 4. Changes of the flowers per nodes due to planting time.

per plant was higher in the early planting than in the late planting in all of the soy­beans tested (fig. 5).

When planted on May 5, the ratio of the seed weight to the total plant weight was high in the summer soybean types, though the soybeans of the summer soybean types which are different in their native lands showed the different ways of response to the planting time as reported previously on the stem length (NAGATA 1951). While the ratio was low in the autumn soybean types, and medium in the intermediate types. On the contrary, when planted on June 25, the autumn soybean types were rather high in the ratio than the summer soybean types.

As noticed in the experiment I , flowers per node appeared in a similar trend as the ratio of the seed weight. And then, the number of flowers per node was consistently more in the autumn soybean types than in the summer soybean types when planted on

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FIG. 5. Comparison in the percentage of seed weight to total weight of plant between the early the and late plantings.

7

PLANTiID PLANTED

6 MAY 5 J\JllS 25

2

L..::-"--....... ~~~. !

S SII MAAA S SMMAAA l k h l' II III IV V VI VII I k h P tl nl I V v VI V"

FIG. 6. Comparison in the number of flowers per node between the representatives of summer VS. autumn soybean types planted at the early and the late times.

SIIr.(in Kyiishii) 1·Wasedaizu No. 3, 2·Shirasaya No. 1, Slh(in Hokkaidii) 3·0yaji No.2, 4·Ishikarijiro No.1, SIp(in Manchuria) 5·Zi.hua No. 1, 6-Gin.yan No.1, SlI ; 7· Wasedaizu No.1, 8·Aoji, M][; 9· Wasekin, lO·Takiya Jun No.1, MlV­ll-Mlzukuguri, 12-Mejiro No.1, AV; 13·Akazaya, 14·Tamba. guro, AlV; 15-Tamanishiki, 16·Banseldaizu No. 30, A VI; 17·Akazaya Shirodaizu, 18-Kiiro Akidaizu.

99

XII, 1960 Series: Agriculture

June 25, though no significant difference was found between those of the summer vs. autumn soybean types when planted on May 5 (fig. 6).

Thus, from the results of two experiments we were able to conclude that the seed yields of the summer vs. autumn soybean types affected by the planting time are substantially attributive to the number of flowers, and not to the percentage of pods to flowers and the seed sizes.

Behavior of the Flowering Process

Since it was ascertained that the number of flowers was of direct attribute to the seed yields of the summer vs. autumn soybean types, as men­tioned previously, the behavior of the flowering processes should be considered in deteail herein.

Results of the daily observation of flowers during the flowering period of each soybean and each planting time were illustrated by fig. 7.

In the figure, it is clear that the summer soybean type, Aoji, bloomed the most abundant flowers per day in the early planting namely April 10, 25, and May 5, and decreased the flowers to' wards the later plantings, whereas the autumn soybean type, Akazaya Shirodaizu had the blooms per day most plentifully when planted on June 10 and 25, and decreased the blooms towards the early

~ ~

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AOJI HZJIRO NO.1 AXAZAYA Slllr.ODA 1L.U

.... _ .. .. - ...... ..

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1317212529 1 5913 171125 Z9/ 5 913 /721 ? 293337 IIUMDER OF DA YS AFTER BEOIIDIING OF FLOW.lIIUNG

and late plantings. The intermediate soybean type, Mejiro No. 1 was medium in the change of daily blooms due to the planting time.

Besides, it is also observed that the change of the flowering period according to the planting time was less in Aoji and Mejiro No. I, and greatest in Akazaya Shirodaizu, though there was a general trend decreasing the days of flowering period to­wards the later planting in all three soybeans. Consequently, the moderate length of flowering period, approximately 25 days in the figure, was observed in April planting of the summer soybean type and in June planting of the autumn soybean type. And then the planting times of both coincided with the planting times of the most abundant blooms per day mentioned above.

Thus, it is concluded that the flowering of the summer soybean type is carried out in the moder­ate length of the duration and abundant in the number of flowers per day when planted in April which is the time of the farmer's practices, while the flowering of the autumn soybean type is pro­longed beyond the moderate duration to too long a period and with few flowers per day when planted in April, and is moderate in the duration and abundant in flowers per day when planted in June which is the time of the farmers practices of the soybeans. The intermediate type is medium

in the planting time of moderate duration and of abundant daily flowers.

The varietal differences in such plant­ing times of favorable flowering were as­certained in the experiment 2 (fig. 8).

Of the eighteen varieties of soybeans tested, the summer soybean types did not show the significant difference between the flowering processes of both planting plots on May 5 and June 25, while the autumn types planted on May 5 had a much longer duration of the lower modal curve of flowering than that of June 25 planting. Six soybeans belonging to the classes of A V, A VI and A VI[ showed the plentiful blooms during the moderate period of 20 to 25 days in plots of June planting. Four soybeans of the intermediate types, name­ly MlJ[ and MIV did not show so clear differences between the flowerings of both plots of planting as in the autumn soybean types.

FIG. 7. Comparison in the summer vs. autumn soybean types with respect to change of the behavior of

Among the soybeans of the summer soybean type, two of Manchurian soybeans (SIp) had the comparatively long duration of flowering in both plots of planting, but there was no significant difference in the flowering process between both of the plots. flowering process due to the planting time.

100

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

1. WASED.HZU SIk

NO . , ""~""""'-"""'--------1 2 . 51lIRASAYA ~...-

13. AKAZAYA A V

NO. 1 ~/~'~~~~-----1 Slh , . OYA.JI 110. 2 \-'_= _______ --1 14 . TAl'LBA

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NO . 1 ~

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~LANTBD ON -- Jo'lAY 5 ._---- JUl~ 25

FIG. 8. Comparison between the behaviors of flowering processes of the summer vs. autumn soybean types planted on May 5 and June 25, 1951.

Thus, the number of flowers and the behavior of the flowering processes appear most substantial­ly attributive to the summer vs. autumn soybean types which are in response to the change in the seed yields that is due to the planting time. Con­sequently, the factor affecting the number of flowers

and the behavior of flowering seems most important in considering the adaptation of soybeans to the planting time, and then the factors that assumed to have such an effe-:t should be investigated in the next chapter.

2. Effect of the Daylength After the Flower Primordia Initiation on the Flowering Process of the

Autumn Soybean Type in an Ecological Aspect of the Planting Time

From the experiments mentioned in the last chapters, the following facts should be summarized: (1) . The variation of the seed yields of the autumn soybean type corresponding to the planting t ime depended rather on the flowering process than on the percentage of pods to flowers. (2). The autumn soybean type had more flowers of moderate dura­tion when planted in June, but fewer ones of long duration when planted in April, while the summer soybean type had abundant flowers of moderate duration when planted in April.

It is also ascertained by the author in the other experiments that the said flowering habit was less affected by such cultural practices as spacings, fertilizers, pinchings, transplantings, and the spray­ing 2, 3, 5-T.

The response of soybeans, above all, of autumn soybean type to the time of planting should be

101

considered to be of truly phenological phenome­non. The author had concluded that the differenti­ation of the summer vs. autumn soybean types rather depended in the seasonal variation of the daylength than that of the temperature, and that the day length had a unique effect on the flower­ing and the seed forming periods after the flower primordia initiation (NAGATA, 1960b).

Thus. the effect of the day length after the flower primordia initiation on the flowering pro­cesses comes to be of great interest for considering the problem of the adaptation of soybeans to the planting time.

Material and Method. Akazaya Shirodaizu soybean was planted on May 5 in 1954 and on April 25 in 1955. Seedings in both years were conducted in the earthenware pots of 27-cm dia­meter filled with fertilized soil, and two plants

XII, 1960 Series: Agriculture

were grown in each pot till maturity. Short-day treatments had been carried out by

using eight plants per plot, as noted in fig. 9.

Effect of the daylengh After the Flower Primordia Initiation on

the Flowering Processes

From such a performance in 1954 as shown in fig. 9, it is noticed that the short-day treatment of

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FIG. 9. Behavior of flowering of autumn soybean type, Akazaya Shirodaizu, as affected by the short day after flower primordia initiation.

Remarks: 9-hour photoperiod started on, 1954; plot I, July 20,17 days prior to flowering.

plot 2, July 30, 7 days prior to flowering. 1955; plot 1, July 25, 5 days prior to flowering.

plot 2, July 31, the beginning of flowering. plot 3, Aug. 9, 10 days after the beginning

of flowering.

this experiment had no effect on the beginning of flowering but on the flowering habit. Then, the flowering period was shortened and the number of flowers per day increased to a great extent. So far as the experiment was concerned, the plants of plot 1 treated after July 20. 17 days prior to flowering, were observed to have less flowers per day as compart'd with those of plot 2 treated after July 30, 7 days prior to flowering. The total flowers per plant were 98.4 in plot 1, 141.2 in plot 2. and 106.4 in the control, and the difference be-

102

tween the flowers of plot 2 and the control was significant at the 1 percent level.

The performance in 1955 presented in fig. 9 clarified the results in 1954 described above in de­tail: The short-day treatment started on August 9, 10 days after the beginning of flowering, had no effect of increasing the flowers per day, but when started on July 25, 5 days prior to flowering, and on July 31, a t the beginning of flowering, it was effective in the same way as in plot 2 in 1954.

From the results illustrated in the figure. it was concluded that the effect of the short-day treatment after the flower primordia initiation was made less in both cases, namely too early (plot 1 in 1954) and too late (plot 3 in 1955) treatments, while it was made more in the treat­ments during the period from a week prior to flowering to the beginning of flowering.

A Consideration of the Adaptation of Soybeans to the Planting Time

From the data obtained in 1955 which were presented in chapter 1, the relation between the seasonal change of the day length and the growing processes of the autumn soybean type is presented in fig. 10. In this figure, the time of initiating flower primordia in each planting plot was esti­mated on the basis of the results of the author ( NAGATA 1950), in which the au tumn soybean type bloomed 30 days after the initiation of flower primordia when planted early, but 20 days after the initiat ion when planted late.

As mentioned in the separate report (NAGATA

1960b) , the variety, Akazaya Shirodaizu, of the autumn soybean type have also been observed by the author to have the critical day length between 14 and 15 hours with respect to flowering under controlled conditions. The critical daylength of the variety is similar to that of maturity group VIl- \1ll in the United States ascertained by PARKER

and BoRTHWICK (1951). In such a phenological view as shown in fig.

11, in which the daylength was estimated on the base of the sun 60 below horizon as HARTWIG

(1954) did, the flowering of soybeans was not ac­celerated under 14-hour day length as compared with a 14.5-hour daylength, but the flowering period was shortened more by the day length shorter than 14 hours. Thus. the day showing 14.5-hour day length becomes most interesting, and it is pointed out to occur on August 13 in fig. 10.

By considering the days of 14.5-hour day length and the growing process of the soybean seeded at successive intervals, it is found that the flowering

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

SUN RISE TO SUN SET

on 14

~ z· ~

x 13 t; .. ~ .. .., Q

12

U 'lt!L • 10 1

25 I t l

WI.Y In ! 10

... 25 r~'

~ JUNE V ... 10

" j 25 .. WI

J U~Y 10

25 VIIl~ __ "'II3!:==~===rQIl====

10 20 30 10 20 30 Ie 20 30 10 20 30 10 20 30 10 20 30 10 20 30 APRIL IlAY J UNE J ULY AUG. SEPI'. ocr.

FiG. 10. Relation between the growing stages of autumn soybean type. Akazaya Shirodaizu, planted at successive times and the seasonal change of day length (at Sasayama, Hyogo, 35° 4' N).

Remarks: s; sown, e; emerged, f.p.; flower primordia initiated, b.f. , e.f.; beginning and end of flower, m; maturity.

started on too early a day when planted early, and on too late a day when planted late, as com' pared with the critical day of 14.5 hours. Then, the early planting corresponds to plot 3 of the 1955 experiment, and the late planting to plot 1 in 1954. In June planting, the flowering started in the period near the day of 14.5-bour daylength, and then the planting in June is closely akin to plot 2 in 1954 and plot 1 and 2 in 1955. Hence, it is reasonable that abundant flowers occured in June planting, especially in the mode of the flow­ering curve in the moderate flowering period.

This relation of the planting time to the day­length after the flower primordia initiation appears to suggest a unique part of the effects of the day­length which has never been noticed before'

As presented by GARNER and ALLARD (1920) first, the autumn soybean type or the late flower­ing soybean is a typical short-day plant, and then the soybean has, hitherto, been mentioned by agronomists in Japan to be adaptable to the late planting by the reason of moderate days to flower­ing and not to early planting because of too long

103

a period to flowering. Many authors have, how­ever, studied the effect of the day length in different ages of plants and observed different effects in each of the growing stages. EGUCHI (1937, 1940) presented the various groups of plants differing as to the effect of the daylength on the initiation and development of flower buds. and recognized the soybean as a plant affected by the short day­length before and after the time of initiating flower paimordia. Moreover, BoRTHWICK and PARKER (1939) , PARKER and &RTHWICK (1951), and FUKUI and Y ARIMIZU (1951, 1952) mentioned that the daylength had different effects on each the flowering and pod development or maturity of soybeans.

Those results should be considered to indicate that, for soybeans. different day lengths are favor­able to each one of the growing stages. This ex­periment of the author also suggests that the day­length after the flower primordia initiation con­trols the flowering period and the number of flowers per day of soybeans, and that the effects of the day length on them differed to some extent

XII, 1960 Series: Agriculture

from those on the flower primordia initiation or the beginning of flowering, as observed in fig. 9 and 11.

>0

90

40 P&R I OD or nonA- 80

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€I ~ ~ 30 60 = !1 >0 ~ iil VII D\YS 1'0 r Ull'1RINO :1 ~ 20

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FIG. 11. Interrelations between the days to flower­ing or the duration of flowering and the daylength, as varied by planting time: - I; April 10, VIII ; July 25 at half month interval.

Thus. we are able to learn that the soybeans, especially of autumn soybean type or of late flower­ing, are best planted at such a time as abundant

flowers bear in the moderately short period, name­ly the favorable period of the vegetative growth to the reproductive growth. It is also noticed that the fact mentioned above is due to the seasonal change of the natural day length affecting the flow­ering processes after the f1(lwer primordia initia­tion . Accordingly the adaptation of soybeans, especially of autumn soybean type, to the planting time has to be considered primarily as the phenolo­gical response due to the variation of the daylength above all other factors.

In Japan, it has been believed by farmers and some agronomists that the decrease of yield in the autumn soycean type by early planting may be prevented by such cultural practices as pinchings, transplantings, spaced plantings, and good manage­ments of fertilizers.' It is also said that a farmer has produced high yields of the autumn soybeans planted early by applying some of the said prac­tices.

The results of these studies, however, empha­size that the adaptable planting time is an obligato­ry factar determining the seed yields of the autumn soybean types in Japan, and that the practices mentioned above are not so effective as to cover all the yield decrease by early planting as described in the introduction of the chapter.

II. SIGNIFICANCE OF THE INDETERMINATE GROWTH HABIT

IN THE CUL TIV ATION AND BREEDING OF SOYBEANS.

1. Agronomic Characteristics of the Soybeans Having the Said Habit

3. Properties of American Soybeans Attributive to their Indeterminate Growth Habit

As an agonomic importance of the indeterminate growth habit, the extensive cultivation of the soy­beans having the said habit in Manchuria and the United States, which are the greatest soybean pro­ducing areas in the world. should be noticed herein. As mentioned previously, the indeterminate growing soybeans are not cultivated for the seed production but for the green manure, in Japan.

Thus, learning the properties of the indeter­minate growing soybeans in the said regions. especially in the United States seems to be of the most necessity for considering the possible signifi­cance of the indeterminate soybeans in further cultivation and breeding of soybeans.

104

Hence, many American soybeans were investi­gated on their maturity groups in direct bearing to the cultivation in 1954 and 1955, and considered on their native lands.

Materials and Methods' In 1954, nine repre­sentative varieties of each maturity group, which were noted in fig. 12, were planted on May 25. In 1955, 56 varieties belonging to each of the maturi­ty groups and to each of utilization groups shown by MORSE and CARTTER (1949) were planted on May 5.

In both years, 13 representatives of our summer vs. autumn soybean types were planted together with the above soybeans as the check plants of the

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No. 2

experiment for comparison.

Relation of the Maturity Group in the United StateB to Our Summer VB.

Autumn Soybean Type

In the experiment of 1954, the following rela­tions were found (fig. 12) ; (1). Maturity groups, O-n, l[-V, and VI-\1I1 were akin to the summer lOybean, the intermediate, and the autumn soy­bean types, respectively, with respect to their days to flowering and days to maturity. (2) The flower­ing period and the seed forming period of soybeans belonging to the maturity group 0-V, which cor­respond to the summer soybean and the inter­mediate types, are comparatively long, and then the relative flowering period and the relative grow­ing period are also long, as arranged on the lines, R.F.= 0.6 and R.G.=2.5 in fig. 12. Most soybeans of the summer soybean type and the intermediate type, therefore, belong to the special summer soy­bean type named by the author ( NAGATA 1950, 1959, 1960a), and the long relative periods seem to result from their indeterminate growth habit (fig. 12, 13).

The same result as the experiment in 1954 was apparently observed in the data of 1955 using

FLOWERING PERIOD

many varieties. Although detailed data were not presented

herein, the characters attributable to the indeter­minate growth habit, such as the increase of nodes after flowering and long stems resulted from the

I>

>0 '

FIG.

o 1 11 nr IV V VT \11 ~111

13. Growth habits of the representative variet ies of the maturity groups in the United States.

Names of varieties were shown in fig. 12.

MATURI TY GROUP O-II lII- V

100 120 160

GROW I NG PERIOD

FIG. 12. Comparison in the growing spans between the maturity groups of soybeans in the United States and our summer vs. autumn soybean types.

R.F.; relative flowering period, R.G.; relative growing period. 0; small seed (determinate), 0 ; large seed (determinate), 0 ; indeterminate (small seed). p-indeterminate.

0 -\I show each of maturity groups. O-Mandarin (Ottawa). I -Blackhawk. 1I -Hawkeye, ][­Lincoln. IV-Wabash. V -Sloo. VI·Ogden. vn-Roanoke. \I-Improved Pelican.

SI-A vn show the degrees of summer vs. autumn soybean habit. s-small seed. L-large seed. SIs-Wasedaizu No.3. SIL-Oyaji No.2. SIp-Zi-hau No.1. S lis-Toppa. MillS-Kimusume No. 77.

MIVS-Mizukuguri. MIVL-Mejiro No. I, MIVp-Sooty. AVL-Akazaya. A VII.-Tamanishiki. Avns -Kiiro Akidaizu. AWL-Akazaya Shirodaizu. AWP-Kurosengoku Kinai No.5.

105

XII,1960 Series: Agriculture

increase which are noted in a separate paper (NAGATA 1960b), were observed clearly in the in­determinate American soybeans.

Relat ion between t he Determi nate vs. Indet er­m in ate Growth H a bit and the Utilization

Group in A merican Soy beans

From the data in 1955, relations among the determinate vs. indeterminate growth habit, the maturity group, and the utilization group in American soybeans were shown in table l.

duced from Japan and China, especially from North Japan, so the determinate habit of the vegetable soybeans is easily understood. It is also reasonable that the soybeans in North Japan which have large seeds and long . relative growing period have been selected for vegetable soybeans in the United States, because the vegetable soybeans are required to have a fair 'seed quality and comparatively a long duration of harvesting.

The forage group of soybeans contains many soybeans introduced from Formosa and China, especially from South China, and then it is also

Table 1. Relation among the maturity group*, utilazation group* and the determinate vs. indeterminate growth

reasonable that the soybeans are of indeterminate growth and of con­sistent vining, namely so-ca lled hay type, and of autumn soybean type for the most part.

.' habit in American soybeans

--

I Maturity Commercial Forage Vegetable

group Det. I Indet. Det. I Indet. Det. I Indet. I - - '---'---I

I I

._--O - II - 15 - I - 5 -I

I I

DJ-V

I 2 10 - I 1 3 -

VI-\lII 10** I 6** - I 6'~* 2** -i ; -* After the list of MORSE and CARTTER (1949) and others.

** Some varieties belong to two utilization groups.

Among the soybeans of the commercial group, the indeter­minate soybeans are mostly intro­duced from Manchuria and adjacent Siberia, and the determinate soy­beans from China and Korea. Such the native lands of ' American soy­beans show a fair coincidence with the distribution of the plant habit

Among the four groups of utilization, the for­age and the vegetable group include only indeter­minate soybeans and determinate soybeans, respec­tively. The commercial group for the utilization, namely the soybeans cultivated for seeds which are sold principally to oil plants is divided into two groups; one is of indeterminate growth habit. and of early or medium early maturity for the most part, and the other is of determinate growth and of late maturity mostly. In other words, the commercial soybeans of the summer soybean and the intermediate types have an indeterminate growth habit, and they belong in the main to a

in the world which was presented previously by the author (NAGATA 1959, 1960a) .

From the result described above, we should learn clearly that the commercial soybeans grown for the seed production are selected for their de­terminate growth habit in both of Japan and the United States as for the group of autumn soybean type. While those of summer soybean and inter­mediate types have been selected in opposite ways, that is, for the determinate type in Japan and for the indeterminate type in the United States. Then, the determinate soybeans of summer soybean type of Japan are of no value for the commercial growing

special summer soybean type and a special non vining type. While those of autumn soybeans type have

T able 2. Native lands of the tested soybeans or their parental strains (after MORSE and CARTTER 1949)

a determinate growth habit for the most part, and then the soybeans belong to a normal type of t he plant habit (see NAGATA 1960a).

The relation mentioned is under-stood more easily by considering the native lands of tested soybeans, as presented in table 2.

Although the table did not in­clude a ll, of the te;;ted soybeans, the discussion on the native lands seems to be available. Soybeans of the vegetable group were intro-

Commercial Forage Vegetable

Maturity «l «l .;:: rn

.;:: rn :::s Ul :::s Ul

group .c: .~ rn rn 0 .c: rn 0 I'l u ... C1l 8 u 8 I'l ' ~

I'l ... I'l .5 rn «l . :a 0

... oj ... p.

::E ~ 0 ::E .c: 0 oj

(f) U ~ U ~ .....,

O-IT 8 1 (2)

]!I- V 6 2*

(1) 1 (1) VI- VIR (1) 1* 3* 2*

I (1) * Some varieties belong to two utilization groups.

( ) Shows the determinate growth.

106

oj I'l :a u

(2) *

Sci. Rep. Hyago Univ. Agric. Vol. 4, No.1

but for the vegetable growing in the United States at present.

Thus, the author shaIl discuss the problem on

the adaptation of the determinate and the inde-. terminate soybeans of the summer soybean type in Japan and the United States in chapter 6 and 7.

4. A Supposed Reason for Cultivating the Indeterminate Growing Soybeans in the Tropics

In the tropics, soybeans are a minor crop of less economic importance, and all soybeans grown in the regions are not of ecological and agronomic adaptation. However, the ecotypical differentiation of the indeterminate growing soybeans in the tropics. which was already mentioned in previous report (NAGATA 1960a) seems to have resulted from reasonable causes.

As clarified previously (NAGATA 1960b), the indeterminate. growing habit attributes to the more increase of nodes after the flowering or flower primordia initiation, and then the plant, in general, is taller than the determinate soybeans. On the other hand, since the tropical climate is of high tempera­ture and short day length, the soybeans in the temperate regions become low in height and poor in yields in the tropics.

Thus, as an important part of adaptation of the indeterminate growing soybeans to the tropical climate, the variation of the growth by day length was examined under the controlled conditions.

Materials and Methods. Experiments were carried out in 1956 and 1957. In 1956, soybeans from Formosa, Malaya, Thailand, Burma, India, Yugoslavia, Algeria, Sweden and Japan, 27 in total, were planted on June 5, in the soil filled in

wooden boxes and grown under nine-hour day­length till maturity. In 1957, many soybeans, 180 in total, from the regions mentioned above, China and other countries in Asia, and European countries including Germany, were planted on May 20 in the earthenware pots of 21-cm diameter. The treat­ment of eight-hour daylength was applied on the plant till maturity.

Stem Length and Yield of Tropical Soybeans under Short Daylength

Results of the .1956 experiment showed clearly that soybeans in the tropics were taIl in the stem with abundant pods in comparison with the soy­beans in the temperate regions. Such a taIl stem and abundant pods as noted above seem to be the results of the indeterminate growth habit of the soybeans, as shown in table 3. However, the con­clusion was not clear because of a comparatively smaIl number of the materials.

The results of the experiment in 1957 are shown in table 4, in which the data were limited within the soybeans in the tropics of Asia from the Philippines to Indonesia and the varieties from the temperate regions were excluded.

Table 3. Comparison in the growth between the soybeans in the tropics and the temperate zone grown under 9-hour day in i956

Country Stem length (cm) or

region 5 10 15 20 25 30 35 Total

Formosa 1 CD ® ® CD 5 Malaya ® 2 Thailand 1 CD 2 Burma CD CD ® 3 India 1 1

Yugoslavia CD CD 2 4 Algeria CD 1 Sweden 1 1 Control* 4® 1® 1 8

Total 119 5 5 2 4 1 27

* Soybeans the in Japan for the most part. o Shows the .indeterminate growth.

107

Number of pods

0 5 10 15 20 Total

1 ® CD ® 5

CD CD 2

CD 1 2

CD CD CD 3

1 1

1 1® 4

CD 1

1 1

5® 1 CD 8 ..

10 6 5 4 2 27

XII, 1960 Series: Agriculture

Within the soybeans grown in tropical Asia , the indeterminate growing soybeans are higher in the stem than the determinate growing ones, and the seed yield measured by the seed weight per piant was fairly high in some of the indeterminate soybeans, whereas most of the determinate soy­beans were low in the yield (table 4, fig. 14) .

Table 4. Comporisons in the growth and yield between the indeterminate and the deter­minate soybeans from the tropics grown

under 8-hour day in 1957

1. Stem length (em)

Growth habit 1 5 10 15 20 25 30 : T otal

. D~t~~ina~~ ·· ! 8 5 -1--1- -- - I 15

Indetermina te I 4 7 10 21 5 3 2 1 2 1 55

._- T~tal __ L ~ __ ~ __ 11 ~_ ~3 2--1 _ ~~~ 70 _

2. Seed yield (g per plant)

Growth hrbit 1-0 O.S 1.0 1.5 2.0 _2.~L2'0_ta_1

-~-:-;-::-;-r:ru-·n-.:-t:-te- \-~ --1~ 1: 1~ ~ ~ 3 3 1 i ~~ Total 2 19 24 12 3 4 4 3 1 I 70

----- --'---------- -

The cultivation of soybeans in the tropical Asia still remains obscure for soybean specialists, and the varieties cultivated in the regions have not been studied in spite of their utililation as hay or forage mentioned previously, and of the use of some disease resistant materials from the tropics for breeding soybeans in the United States (HARTWIG and LEHMAN 1951) .

Of the paddies in the tropics, most varieties have been characterized by their long basic vege­tative period which seem to be available for elon­gating the satlk under the short day length in the tropics (MATSUO 1952) . Jo (1938) has certified tha t such paddies of long basic vegetative growth have been cultivated in Formosa in a season different from the others of short basic vegetative growth.

'Jd-

" I.

I I.

(1957)

FIG. 14. Camparisons in the stem length and the pod bearing between the determinate and the indeterminate soybeans of the tropical regions when planted under the short daylength (8 or 9 hours).

Of soybeans, such a vegetative growing period has not been clarified. and the differentiation of such a period in soybeans seem to be found to less extent than the paddies, as noted previously (NAGATA 1960 b) .

Consequent ly, the indeterminate growing habit should be noteworthy as the character elongating the stem of soybeans under the short day length in the tropics instead of the long vegetative period. Then, the indeterminate soybeans are supposed to be adaptable to the climate of the tropics.

5. Some Genetic Association Between the Determinane vs_ Indeterminate Growth Habit and Other

Agronomic Characters

In order to consider the significance of the in­determinate growth habit in the cultivation and breeding of soybeans, genetic associations of the said habit with other characters are of the most

108

importance, and were described already with respect to some ecological characters such as the vining habit and the summer vs. autumn soybean habit in a separate paper (NAGATA 1960b) .

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

Varietal associations of the determinate vs. in­determinate growth habit to the stem length, seed yield and seed size were already observed (NAGATA 1950, 1960a). The associations, however, were not ascertained genetically, and then the results ob­served in paranel with the genetic associations of the ecological characters mentioned above should be dealt with herein.

Materials and Methods. Observations were made on the same materials as described on the separate paper (NAGATA 1960b). Three crosses were made in 1951 in the Hyogo University of Agriculture, by using the representative varieties of the habits. Plants in the F, generation and families in the F3 generation were measured on their stem lengths, seed yields, and seed sizes.

Genetic Associations between the Characters

Stem length: Stem length of the indeterminate plants or families was compared with that of the determinate ones in relation to the times of flower­ing and maturity, as shown in fig. 15 and 16. The indeterminate plants and progenies were consider­ably taller than the determinate ones in three crosses, and the differences were observed clearly when compared between those of the same time of flowering or maturity.

The influences of the stem lengths of indeter­minate plants or families in comparison with the determinate ones were estimated at about 20-30 cm, as shown in the figures, though the

,,/10 15

>< 20 ... 25 ~ 30 ~10/5

10 ... o '" 20 ~ 25

~o

be capable of being selected from the families of such a determinate and indeterminate soybean cross. Dr. JOHNSON of the Agricultural Research

710

§ ~ !: ~~ ~ 8/4

~ 1~ ~ 19 a ~;

9/'; 10

t: 15 ... 20 ~ 25 i! ~o .. 10/5 o 10

'" l~ !< 20 o 25

W

11/4~C--::'=""'~--0~100 20 40 60

STEM LENGTH (eM)

K5 x M Ki77 x K5 Sx A

FIG. 15. Comparison in the stem length between the determinate and the indeterminate plants in F, generation of three crosses. Figures were made of the means of plants grouped at five-day intervals of flowering or maturity.

K5; Kurosengoku Kinai No.5, M; Mizu­kuguri, Ki77; Kimusume 77, S; Zi·hua No. I, A; Akazaya Shirodaizu. Characteristics of the soybeans were tabulated in the separate paper (NAGATA 1960b).

o DETERMINATE • INDETERMINATE

~ o •

o 0 o ••

o ,~ •• 00 .

80 • • •• 0 0 • n 0000 •

o

~'\ o~~

o

o ~. 00 •

0 0 -. ' •• . . o 0

differences were varied with the crosses and the times of flowering and maturity. The photographs in fig. 17 show the com­parative heights of the parent and F, plants of the cross between Zi-hua No. 1 and Akazaya Shirodaizu which are of indeter­minate summer soybean type and of de­terminate autumn soybean type, respec­tively. The determinate F. plants segre­gated in the range from the shorter stem than Zi·hua No.1 to the same stem as Akazaya Shirodaizu, whereas aU of the indeterminate F, plants were arranged above the parent of shorter stem, and some plants had very long stems exceed­ing the taUer, Akazaya Shirodaizu. Con­sequently the stem length in F. generation of the cross showed a transgressive segre-gation.

14 9"-:'::~::-'-;~-:7::

5.0 70 90 no

~ ..

• 60 80 100

STDi . LIDIG'1'II IN eM

10 ~o 50 70

Thus, the stem length in aU three crosses were significantly associated with the determinate vs. indeterminate growth habit.

Hence, the high stem soybeans may

K5 x M Ki77 x K5 s x A FIG. 16. Comparison in the stem length between the

109

determinate and the indeterminate families in F3 generation of three crosses.

XII, 1960 Series: Agriculture

.. Parent: left , Zi-hua No_ 1 right, Akazaya Shirodaizu ..

.. . Indeterminate

-! at

Determinate

",,1-Ie

~ I

~~l l ., , ..

FIG. 11- Comparison in the stem length between the determinate and the indeterminate plants in F3 generation of the cross between Zi-hua No.1 and Akazaya Shirodaizu.

Service has informed the author by the letter that the indeterminate growing soybeans in the United States might be selected for their taller stem, because the soybeans in the Corn Belt have been improved to be taller in the stem.

Seed Yield : The seed yield of soybeans, in general, is low in the heritability as compared with the stem length and the maturity (MAHMUD and KRAMMER 1951) , that is, more affectable by the environment than the other characters. Then, the association of the determinate vs. indeterminate growth habit with the seed yield is expected to be of difficult investigation .

In the studies, the heritabilities of the seed yield in three crosses were estimated as presented in table 5.

In the table. the heritabilities of three crosses are different somewhat from one another as shown by BARTLEY and WEBER (1953) . In general, the heritabilities estimated on the variances of F, plants and parent which are of a broader sense were signigcantly high in every cross, whereas those estimated on the regression of F, plants to F3 family means which are of narrower sense were very low and not signigcant.

Seed yields in F, and F3 generations are pre­sented in fig. 18 and 19, and then it is found that the seed yield increased towards the late matured

110

Table 5. Heritabilities of the seed yields in three crosses

Cross*

K5 x M

Ki77 x K5

S x A

445

115

180

76. 4%

64. 0

64.3

3.64%

5. 50

8.97

*K5: Kurosengoku Kinai No. 5. M; Mizukuguri, S; Zi-hua No.1, A; Akazaya Shirodaizu, Ki77; Kimusume No. 77.

plants in F, generation, but the seed yields of F3 families decreased in opposite trend towards the late families. Differences in the seed yield between the determinate and the indeterminate plants or families were substantial in the F2 generation whereas not significant in the F3 generation. The seed yields of the indeterminate plants in F2 gene­ration were higher about 5 grams per piant than the determinate plants, and the said difference was apparent in the early and the medium early matured plants, but not clear in the late matured

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

9/1~ ~ z.o ... 2~

~ ~o 2i 10/5 .. 10 o 15 i::! 20 ~ 25

~o

o

~ :i::mr~ ,,"', , , ,,,, ~

SEli:D WEIGHT PE:!! PLAN'!' IN GlW1~

K5 x M Ki77 x K5 S x A

FIG. 18. Comparison in the seed yields between the determinate and the indeterminate plants in F, generations of three crosses.

Figures were made of the means of plants grouped at five day intdrvals of maturity.

plants. Although the difference in the seed yield between the determinate and the indeterminate families in Fa genera tion was not significant, there was a difference in the seed yields between the early matured families of both habits. and the dif­ference became obscure towards the late families which were all poor in the yield.

Consequently, it seems to be concluded that the indeterminate soybeans have potential abilities of yielding seeds more than the determinate soy­beans. and the difference in the ability between them is rather more in the early or medium early matured soybeans than the soybeans of late maturi­ty, and that such a difference in the yielding abili­ty between the said soybeans is affectable largely by the environments.

The fact that the difference in the yields be­tween the determinate and the indeterminate soy­beans is not significant in the late matured soy-

~10 15 20

>< 25 E:: ~o t3 10/5 ~ 10 ~ 15 ~ 20 Cll 25 !< }O

" 11/4

o DETERHINATE • I NDE"rEP.MI.NATE

~o

o .' ~ . . 9(\);-~-;'1~0 ---71';'5- 0 5 10 1 5 0 0 10 15 20

S!iED wsroll'l' PER PLANT IN GRAMS

K5 x M Ki77 x K5 S x A

FIG. 19. Comparison in the seed yields between the determinate and the indeterminate families in F, generations of three crosses.

beans seems to correspond to other facts mentioned in chapter 3, that is, the indeterminate and late matured soybeans are of less importance for the commercial cultivation in the United States, in spite of the importance of the indeterminate and early matured soybeans for cultivation in the Corn Belt, principal soybean cultivating region in the United States.

Seed Size: The association of the growth habit with the seed size was investigated on the cross between Zi-hua No. 1 and Akazaya Shirodaizu by the reason of a large difference in the seed sizes between the parent. The relation between the two characters indicated in table 6, appeared to be in a contrary trend to the results of varietal interre­lation which was already presented (NAGATA 1950, 1960a) .

Within the varieties cultivated at present, the indeterminate soybeans have the small or medium

Table 6_ Interrelation between the determinate vs. indeterminate growth habit and the seed size in F2 plants of the cross, Zi-hua No. l x Akazaya Shirodaizu

Wt. per 100 seeds (g) Total Mean I Flowering

I -- -----

July

Aug.

- .

Total

5 10 15 20 25 30 Dt. Ind. Dt. Ind.

10

15 1 1 2 1 3 2 13.5 20.0

20 2 3 3 9 2 5 14 15.5 17.0

25 5 7 11 26 2 4 18 37 16. 7 16.8

30 112 7 20 3 5 11 37 18.4 16.5

4 2 6 4 21 2 6 29 15.9 16.8

9 2 9 3 8 5 17 14.5

14 6 6 17.5

1 12 30 5 48 16.1 38 90 13 1 142 16.7

Gothic type shows indeterminate plant, and other is the determinate plant. * Singificant at 1% level

111

Diff.

- 6.5

-1.5

- 0.1 1. 9*

-1.0

1.0

- 0.6

XII, 1960 Series: Agriculture

small seeds for the most part, and the soybeans of large seeds are very few, whereas the deter­

minate soybeans consist of the soybeans of different seed sizes. In the segregating generation after the cross, however, there was no difference in the

seed sizes between the determinate and indeter­minate plants.

In F3 generation, the comparison of seed sizes was made in fig. 20, and no difference was found between the seed sizes of the determinate and the indeterminate families. Moreover, the variation of

seed sizes was larger in the indeterminate families than in the determinate families. Hence, the large seeded soybeans are likely to be selected from the indeterminate families.

Thus, it should be concluded that the varietal association of the determinate and indeterminate growth habit with the seed sizes is not of genetic

° m:TERI'lINATE

7/10 • I NDETERMINATE

15 a

'" z H

20 • • '" • • •• f: 00 • 0 0 25 ~ a ... 30 0

. 0 0 0

i'l 8/1. •• el

9 00

\~~.-0~~1~5~,0~~2~0~.0~~2~5 . 0 100 SE;;:O "'EIGlIT(G)

FIG. 20. Comparison in the seed size between the determinate and the indeterminate families in F3 generation.

association, and it is perhaps the result of ecological and agronomic selections.

III. SIGNIFICANCE OF THE INDETERMINATE GROWTH HABIT IN THE CUL TIV A TION AND BREEDING

OF SOYBEANS. II. Regional Adaptabilities of the Principal Varieties of the Summer

Soybean Type Cultivated in Different Regions

6. Cooperative Performances in Japan

In the experiments, it was attempted to know the adaptabiJities of soybeans which are cultivated in Hokkaidi5 and KyUshu. and have never been cultivated in each other region. Moreover, it was expected to know the adaptation of Manchurian and American soybeans in Japan and the possible value of introducing them.

Materials and Methods. Experiments were carried out at Sasayama, Hyi5go (36°4'N), Sapporo, Hokkaidi5 (43°3'N) and Nishigoshi, Kumamoto (32°53'N).

In 1955, each three varieties fro~ KyUshU, Hokkaido, Manchuria, and the United States, 12 in total, were used.

In 1956, ten varieties from KyUshU, eight from

Hokkaido, six from Manchuria, and nine from the

United States, 33 in total , were used.

The times of planting were as follows: Hok­

kaido-May 18 (1955), May 13 (1956), Hyogo- May

5 (1955), May 13 (1956), and Kumamoto- April 12

(1955 and 1956).

112

Comparisons in the yields and Qualities of Seeds

In the 1955 experiments, the result of seed yield in HyOgo was disturbed by insect damages, mainly due to the green rice bugs, Nezara anten­nanta ScOTT.

The seed yields of materials in Kumamoto were arranged along regression lines to the days to maturity, as shown in fig. 21. In the figure, three varieties from Hokkaido were arranged along the lines of the lowest yield. When the days to maturity was noted as x and yield as y, the soy­beans from Hokkaido were near the line showing the first equation, y =0.33x - 26.7. The varieties of KyUshU lay on the line of the medium yield, y = O.33x - 23.3. While, other two groups of the in· determinate growth, namely Manchurian and Ame­rican soybeans were distributed within the from the line of y =0.33x - 20.0 to the line of y =0.33x-16.6.

Consequently, KyushU soybeans were more yielding than HokkaidO soybeans by 3.4 g per plant,

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No. 2

_ 11(:'

~ ~ 110

~ 105 ;i 0 100 ..

135

E 13

~ 12 >! g 120

CIl

~ 115

110

BOKKAlDO

o KYUSHU

o I!OKKAIDO

.. ~!AIICilURlA

• U. s. A.

10~~~~1~O~~1~~--~~~~--~~~~--L

SEED .'EIGlI'I' PER PLA1.T IN GRAMS ( y )

FIG. 21. Seed yields of soybeans compared with the days to maturity in the cooperative tests in Japan (1955) .

Varieties; (Kyushu) I ·Wasedaiza No.1, 2-Shirasaya No. 1, 3·Matsuura, (Hokkaido) 4·0kuhara No.1, S.Oyaji No.2, 6·Shiro Tsurunoko, (Manchuria) 7· Zi·hua- No.1, 8.Huang-bau·zhu, 9·Xiau-gin·huang No. 1, (U.S.A.) 10·Mandarin (Ottawa), ll-Harosoy, 12-Lincoln.

o- small seed O-Iarge deed, .... -indeterminate growth.

and Manchurian and American soybeans were more yielding than the KYUshil soybeans by 3.3 to 6.6 g per plant, when compared between the varieties of the same maturity.

In other words, KyushU soybeans gave the same yields as the varieties from Hokkaidi5 matur­ing 10 days later, and Manchurian and American soybeans also could yield the same seed weight as the varieties trom Kyilshil maturing 10 to 20 days later.

y ~ 0.59x - 27.4. Thus, the indeterminate soybeans yielded approximately 10 grams more seeds per plant than the determinate soybeans, as compared among the varieties of the same yields as the de­terminate soybeans maturing about 20 days later for the most part. However, the difference in the seed yield between the soybeans of Hokkaido and KyUshU was not found in the experiment of Hok­kaido.

In the 1956 experiments, the relation of the seed yields of the tested soybeans to the locations of CUltivation was not so significant as in 1955 and appeared to some extent in the opposite trend.

In detail , it was observed as follows: (fig. 22) i. In Hokkaido, the differences in the seed

yields between the groups of the soybeans were comparatively clear to those in 1955, while the dif­ferences in the seed yields between the groups of soybeans in KyUshll were shown to be less signifi­cant than those in 1955. In Hyogo, the differences

HOKKAICO

){yOGO

. •

o KYUSHO

ROKKAI.DO: o 1,.AH~ SZEP • SJII.ALL SE:W ... IoWICHU Rl " • u. s . A.

In Hokkaido, the results of the 1955 experi- 1

ment did not show so significant differences be-tween the groups of soybeans as in KYUshU, but there was a difference in the seed yields between the determinate soybeans in Japan and the indeter­minate soybeans from Manchuria and the United States. The seed yields of four varieties in Japan were arranged with the line of y =0.59x - 41.0, and four of the indeterminate soybeans in Manchuria and the United States lay along with the line of

113

F IG . 22. Seed yields of soybeans compared with the days to maturity in the cooperative tests in Japan (1956).

XII, 1960 Series: Agriculture

in the seed yields between the groups were inter­mediate between both of the said regions.

ii. The indeterminate soybeans of Manchuria and the United States were higher in seed yields significantly than the determinate soybeans in Japan when investigated in Hokkaido, and then the formers were arranged between the lines of y =0.5x - 75 and y=0.5x - 50, and the latters were distributed between the lines of y = 0.5x - 50 and y=0.5x - 30 for the most part. Consequently,

In the results of the 1955 experiments, the percentages of inferior seeds were less in the soy­beans from Kyushu than the soybeans from other lands, and the fact is true in the experiments of Kumamoto (fig. 23) and Hyogo. Besides, the soy­beans from Kyushu, in general, were low in the percentages of the infnrior seeds than the other groups of soybeans in 1956, though there was a considerable variation of the varieties within each

there was a difference in the seeds per plant of about 10 to 20 grams between the determinate and the indeterminate soybeans when compared between the varieties of the same maturity. Such a difference was limited to about 6 to 10 grams in Kyushu and Hyogo.

200

180

160

fJ 11,0

"' '"

~-~~. ~~~ CRAClIED

WR INKLED

1:! ROWN BLOCHED

lll. In comparison of the soybeans of Hokkaido with those of Kyushu, it was found that most of the latters were

., ~

~

1 30

1 20

100

4C higher yielding than the former, and such a trend was clearer in Hokkaido than in Kyushu and Hyogo, though the differences were not so significant as in comparison of the determinate soy-

: 1 2 ~ I ~ J ~ 71

' 9 1 0 IH2 1~I41S1 171P, , 0202J2227,2L >- 26272829,0 ,,,? \..I . S. A. KYlISHl} HOKl<A1DO

VARIETY us:m beans to the indeterminate ones.

Seed qualities: Seed samples con­tained different kinds of abnormal and

FiG. 24. Inferior seeds appeared on the samples of the soybeans tested in Kumamoto in 1956.

inferior seeds which consisted of the seeds covered with a wrinkled seed coat, cracked seed coat, and brown blotched seed coat, and other seeds damaged by insects, diseases and weather.

Such inferior seeds were few in Hokkaido whereas appeared in notable rates in Kumamoto and Hyogo, and the rates are different between the groups of soybeans.

1.60

,,140

~120 gj .. 100 ... o 80

5 60 ~ .. 40

~o

I" CRACKED

WRINKLED

BROWN B~OCJI£D

1 ~

KYlJ31!U 4 5 ,l!OKKAIDO

FiG. 23. Inferior seeds appeared on the samples of the varieties tested in Kumamoto in

1955. Names and characters of the varieties were noted

in fig. 21. Since the percentages of the seeds estimated separately were added in the figure, the total percent became more 100 percent. (All varieties of Kyushii had no inferior seed) .

114

group of soybeans (fig. 24) . Thus, the seed quality should be noticed for

considering the adapatabilities of soybeans, and then the determinate and' small seeded soybeans which have a short relative growing period were considered to be cultivated in South Japan by a reason of their fair seed qualities.

It, however, is noticerl in fig. 24 that selecting the soybeans of a fair seed quality, when cultivated in South Japan, should be expected from the indeterminate soybeans, especially of the United States.

Correlations of the Seed Yields to the Yield Components

In order to consider the reason for varietal differences in the seed yields according to locations, the correlations of the seed yields to the yield components were investigated (table 7).

In the results of the 1955 experiments, the partial correlations which held the days to maturi­ty constant were high between the seed yields and characters concerning branching such as the number of branches, total lengths of branches, and total numbers of nodes of branches in Hokkaido, whereas the said correlations were rather high between the seed yields and characters concerning

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

stems such as stem lengths. numbers of stem nodes than those of branches in Kylishli. Moreover, the partial correlation between the seed yields and total weights per plant including the stalks, pods and seeds was higher in Kylishli than in Hokkaid6.

The growth of the soybean plant was signifi­cantly poor in Kumamoto as compared with that in Hokkaid6, and then the stem elongation seems to be very important for increasing seed yields in Kumamoto. It, thus, is supposed that highly sig­nificant correlations of seed yields to the characters of the stem and the plant weight were resulted from such a poor growth in the location.

Hence, it is reasonable that the indeterminate soybeans of Manchuria and the United States were more adaptable in Kumamoto of Kylishli than in Hokkaid6 because of their long stems and much weights.

In the results of the 1956 experiments, how­ever, the partial correlation which held the days to maturity constant was high between the yields

and lengths of stem or the numbers of stem nodes, but low between the yields and the number of branches in both locations, namely Hokkaid6 and Kylishli (table 8). In other words, the difference between the partial correlations of both locations in 1955 did not appear in the performance of 1956,

As a supposed reason of such partial correla­tions in 1956, it may be pointed out that the cool summer in Hokkaido in 1956 inhibited the growth and decreased the seed yields, and then the stem elongation above the first flowers of the indeter­minate soybeans appeared to be contributory to yields in Hokkaid6 as well as in Kumamoto.

Conclusion

From the performance in both years, it appears to be concluded that the indeterminate growing soybeans are perhaps adaptable to the cultivation under the conditions resulting in a poor growth of the soybean plant, such as the cultivation of the

Table 7. Correlations between the seed yields and yield components in Hokkaid6 and Kumamoto (1955)

Character

Stem length

Nodes of stem

No. of branches

Total length of branches

Total nodes of branches

Pods per plant

Wt. per plant

Wt. per 100 seeds

Days to maturity

Simple correlation

Hokkaid6 -_._--

+ .864**

+ .678*

+ .544

+- .766**

.784**

-I- .670* -(- .764**

.179 'j- .785**

Kumamoto

+ .838** .858** .204

.838**

.699* -I .779**

.907**

.496

.678*

Partial correlation l )

Hokkaid6 Kumamoto ------ _ ..

.623** l- .761**

.627* -I- .766**

.654* .004

.658* -j' .533

.940** .585*

.775* .683*

.503 -I- .821**

.747** .899**

- ----------

1) When the days to maturity were held constant. * Significant at 5% level. ** Significant at 1% level. d.f. = 10 in simple the correlation, and 9 in the partial correlation.

Tabte 8. Correlations between the seed yields and yield components in Hokkaid6 and Kumamoto (1956)

Character

Stem length

Nodes of stem

No. of branch

Total nodes of branches

Simple correlation

Hokkaid6 Kumamoto

.637** -I- .779** -]- .498** -I- .471**

.185 .157

-I- .601** .371*

1) When the days to maturity were held constant.

Partial correlation l )

Hokkaid6 I Kumamoto I

. - ._----- ----- --_ ..

+ .640** -I- .753**

-I- .486** .648**

.178 .175

.595** .043

* Sifinificant at 5;?6 level. ** Significant at 1;?6 level. d.f. c 30 or 31 in the simple correlation and 29 or 30 in the partial correlation.

115

XII, 1960 Series: Agriculture

short season crop in Kyiishii, and the cultivation under the extremely cool summer in Hokkaido in 1956. Accordingly, the introduction of the indeter­minate soybeans of ecotype manchuriensis (NAGATA 1959, 1960a) to Japan seems to be of possible value under such a cultural condition or location.

In reference to the regional adaptabiIities of the soybeans of Hokkaido and Kyfishfi, the seed yields of those soybeans did not present the sig­nificant differences between the locations. How­ever, the performances in Kumamoto in 1955 showed somewhat predominant yields of Kyfishfi soybean varieties over the varieties of Hokkaido, and the performances in 1956 also presented that most of Kyfishfi soybeans examined were more yielding than the ones of Hokkaido in both locations of Hokkaido and Kumamoto, though the differences were not so clear as in Kumamoto in 1955. Thus, the difference between the adaptabilities of the

said soybeans should be noticed to some extent. Moreover, the seed quality of the' materials

may be showing the adaptabilities to the location of the materials, and then the soybeans of Kyushfi seem to be adaptable to the cultivation of the short season crop in Kumamoto in comparison with the other soybeans such as the determinate soybeans of Hokkaido and the indeterminate soybeans in Manchuria and the United States which are being grown as the full season crop in the said regions.

Thus, the ecotype japonicus australis is con­sidered to be of ecological adaptation to the habitat which separated from the habitats of ecotype manchuriensis and ecot. japonicus borealis.

However, it should be added that the fair seed quality of the indeterminate soybeans in Kyiishfi district shall be expected by further selection from the said soybeans with a high yielding ability mentioned above.

7. Cooperative Performances in the United States of America

Cooperative studies were carried into execution in the Regional Soybean Laboratory, Urbana, Illinois in 1956 and 1957 and the Delta Branch Experiment Station, Stoneville, Mississippi, in 1956, 1957 and 1958. However, the performance of 1956 in Missis­sippi failed unfortunately to get the seed yields, though the detailed data for growth were informed to the author by Dr. HARTWIG. Moreover, the test of 1957 in Mississippi could not obtain the data for the failure of emergence by the accidental dry weather. In the southern part of the United States which corresponds to South Japan with respects to the latitude and climate, the soybeans of the summer soybean type have not been grown as shown by HARTWIG (1954). Such a fact might be attributive to the abnormal dry weather at the times of planting and harvesting, because Dr. HARTWIG informed the author that the early soy­beans planted at an early time such as April failed to yield the commercial seeds according to a failure of emergence, and poor quality or heavy shattering of pods.

Therefore, the performances in the United States should be described mainly on the results of Illinois which corresponds to Hokkaido in Japan, and additively on the growth of the soybeans in Mississippi in 1956 and the yield in the location in 1958.

Materials and Methods. The varieties used in the experiments are the same ones as in the experiments in Japan. namely 12 representative varieties in 1956, and 33 representatives in 1957 and 1958.

116

In the 1956 experiment in Illinois, seeds were sown on May 9 on 40-inch rows of seven-feet length with two replications. In the experiments in Mississippi, seeds were sown on April 23 on single rows 19-feet long with two replications. The interval of plants on the row in both locations was somewhat different between the varieties, since the emergences of the seeds were not uniform and then the plants did not spread evenly.

In the 1957 epxeriments in Illinois, seeds were sown on June 2 in rows eight-feet long and 40-inch wide. The plots were not replicated and the seed­ing rate within the plots was 50 seeds per plot.

In the 1958 experiment in Mississippi, seeds were sown on May 28, in a single 4-row plot 19-feet long in each variety.

Comparisons in the Seed Yields and the Sha tterings

From the data of Illinois in 1956, the seed weight per plant of each variety was compared with the days to maturity in fig. 25. Two groups of Japanese soybeans were arranged along with the line of y=0.4x-28, but the soybeans of Man­churia and the United States lay along with the line of y=0.4x-16 for the most part. Hence, the indeterminate soybeans of Manchuria and the United States yielded more about 12 grams per plant than the determinate soybeans of Japan when compared between those of the same maturity. In other words, the seed yields of the indeter­minate soybeans were the same as those of the

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

determinate soybeans maturing 30 days later. In the performance in 1957. japanese soybeans

were arranged between the lines of y cc O.0167x 1.33 and y ·~ 0.OI67x · 1.00. and the soybeans of Manchu­ria and the United States were also distributed between the lines of y 0.OI6h -1.00 and y

0.OI67x 0.67 (fig. 26) . Thus. it was also observed that the indetermi ­

nate soybeans of Manchuria and the United States

1}0 o KY1JSHU

o HOKllAlOO

H .. MANCHUHlA

~120 • U. S . A.

H

~ ;! llO 0 ... ~ 2Q ! 100

90 0 2~ 30 }')

SEE D loI~IGHT PER PLANT IN GRAMS (y)

adaptable to the cultivation in the Corn Belt in the United States for their higher yielding abilities than those of the determinate soybeans of ecot. japonicus borealis and japonicus australis.

Other agronomic characters such as the seed qualities and lodgings did not appear to have the significant differences among the groups tested. but the shattering percentages of the japanese soybeans were significantly higher than those of the soy-

• 12

40

beans from Manchuria and the United States. as shown in fig. 27. Such a dif­ference between the soybeans remains to be known if it is attribl.lt.ive to the deter­minate vs. indeterminate growth habit. But there is perhaps a kind of relation between the shattering and the growth habit. It is likely to be true that the long seed forming period or the gradual course of the maturity of the indeterminate soy­beans mentioned previously seems to as­sociate with the less shattering character.

Hence the shattering is a character of

Fig. 25. Seed yields of soybeans compared with the days to maturity in the cooperative test in Illinois (1956). Names of the varieties used were noted in fig. 21.

the most importance for the breeding of soybeans in the United States in spite of less value for the breeding of soybeans in japan, the difference shown in fig. 27 seems to be notable on the ecotypic dif­ferentiation of soybeans in japan and the

were more yielding 170 to 500 grams per plot than the determinate soybeans of japan when compared between the varieties of the same maturity. In other words. it was observed that the indetermi­nate soybeans gave the same yields as those of the determinate soybeans maturing about 10 to 30 days later.

It. therefore. was concluded that the indeter­minate soybeans of ecotype manchuriensis were

o ImlSHU

o aOKl\AlOO

SZU> WEIGHT PER PLOT IN KG . (Y)

FIG. 26. Seed yields of soybeans compared with the days to maturity in the cooperative test in llIinois (1957).

117

United States. The yield performance in 1958 in Mississippi

was presented in fig. 28. From the result, it is noticed that the soybeans of determinate growth habit in japan were divided into two groups, namely one which is of low yield and arranged along with the lines of y ·· 0.4x ~ 30 and y - 0.4x ~ 26, and the other which is of high yield and distributed in the

DA'fe OP OB?oEhVAl'lO)l

FIG. 27. Comparison in the shattering between the soybeans used in the cooperative test in Illinois (1956). T; trace, M; time of maturity.

Names of varieties were noted in fig 21.

XII, 1960 Series: Agriculture

o KYUSHU

o HOllllAlDO

4 ~F.;m YTF.1,D PI'" 'CRR IN BUSHELS(y)

Fig. 28. Seed yields of soybeans compared with the days to maturity in the cooperative test in Mississippi (1958) .

area from the lines of y = O.4x ._-22 to the line of y ~0.4x - 14.

In the groups, the former consisted of the soy­beans from Hokkaido, and the latter of the varieties from Kyushu.

Most of the indeterminate soybeans from Man­churia and the United States are distributed in the area between both the groups in the figure.

The prevalence in yields of KyushU soybeans seems to be the similar result to that in 1956 in Kumamoto in Japan. as presented in the last chapter.

The superiority of KyushU soybeans in Missis­sippi appeared in their seed quality. as shown in

table 9.

Table 9. Comparison in the seed quality between the soybeans used in the cooperative

test in Mississippi (1958) ,-

Native land I Grade of quality Very [Total

of soybeans I Very Good Fair Poor I good . poor i

KyushU 4 5 1 10

Hokkaido 4 4 8

Manchuria 1 3 2 6

U.S.A. 1 5 3 9 - --- ---, --

Thus, the determinate soybeans of ecotype japonicus australis appear to be of possible signifi ­cance for the cultivation of soybeans of the short season crop in the southern part of the United States. As mentioned in the introduction of the chapter. however, the dry weather and other phe­nological conditions of the region are not favorable for such cultivation of soybeans as in South Japan . And then, the soybeans of ecotype japonicus aust­ralis are not of practical use at present, but some economic value of the soybeans shall be found in

118

the United States at the time of future.

Correlations of the Seed Yields to the Yield Components

In the Illinois experiments in both years, no detailed data for the growth of soybeans was ob­tained, and then the correlations of seed yields to the stem length will be discussed below.

A simple correlation between the said characters and a partial correlation between them when the days to maturity was held constant, were presented in table 10, and the strictly significant relation between them was found in both years.

Such correlation coefficients are as high as those in the experiments in Kumamoto in 1955 and Hokkaido and Kumamoto in 1956. Although there was no survey on the characters of branch­ing, the correlations of the said characters to the seed yields are presumed to have been compara­tively low as in Kumamoto. 1955. and in Hokkaido, 1956.

The correlations in Mississippi were also high­y significant, but the values were rather lower

than those in Illinois (table 10).

Table 10. Correlations of the seed yield to the stem length of soybeans used in the cooperative tests in the United States

Location Year I d.f. Simple d.f. I PartiaP l

Illinois O. 718** 9 . 0. 737** 1956

1957

10

31 0.812** i 30 I 0.960**

Mississippi I 1958 I 31 0. 610** 30 ' 0.613** . - -- --- - ----- . . -

** Significant at % level. 1) Maturity held constant

It, however, should be noticed herein that the plant growth in Illinois was quite as good as com­pared with the results in Japan in fig. 29. In the figure, the average lengths of stem in the deter­minate growing soybeans and the indeterminate growing soybeans were presented, and it was ob­served that the stem growth in Illinois was equal to that in Hokkaido, 1955, and better than those in Kumamoto and Hokkaido, 1956.

Consequently, the mechanism of the superiority of the indeterminate soybeans in Illinois should be considered somewhat different from those in Japan. The factors concerning the mechanism were not fully clarified in the studies. HOLMBERG (1955) has emphasized that the Japanese soybeans appeared to be adaptable to the insular climate of Japan and Sweden, and the Manchurian soybeans to the con­tinental climate of Manchuria and the United

Sci. Rep. Hyogo Univ. Agric. Vol. 4. No.2

90

" 80 ~ 70 .... 60 r; 50 ~ 40 ... 30

~ 20 Q) 1 0

191 6

HOKKA I DO

1955 1956

n I LLI NOIS H1SS1SSIPPI

O DETER-lUNATE

I INDE1!l>R' ""'''''''I,,,p,

FIG. 29. Comparison in the stem length between the soybeans grown at four locations of cooperative studies. The graph shows the mean of each group of the determinate and the indeterminate soybeans.

States. Although the adaptabilities have not been discussed in detail, his opinion is likely to be true in some point of view.

As to the other aspect of the adaptation of soybeans, the author should like to notice the dif­ference in spacing between japan and the United States. Soybeans, in general, are planted in a spaced rate mostly in japan, but in a solid rate, especially within the row in the United States. In the cooperative experiments in Illinois, the average stand in the row was five plants per foot in 1956, and fi fty seeds were sown on the rows of eight feet in 1957, and then the distance between the plants is calculated as about 5 to 8 cm. Such planting rates in the United States are two or three times as large as the rate in japan.

As a general view concluded to date, a solid planting restricts the branch and elongates the stem. And then the indeterminate growing soy­beans are likely to be prevailing over the deter­minate growing ones in the solid planting, and in the opposite trend, the latters should be grown better in a spaced plantung than the formers. The difference in the adaptability between the determi­nate and the indeterminate growing soybeans, how­ever, will be ascertained in further studies.

In Mississippi, the stem growths of the plants were rather poorer than in Illinois and approxi­mately correspond to those in KyushU as shown in fig. 29, and other characters of the plant growth

119

were observed to be also near akin to those in Kyushu, though the detailed data are not presented herein .

Discussion

As appeared on the seed yields and the growths mentioned above, the extensive cultivation of the indeterminate soybeans of the summer soybean type in the United States SMms to be reasonable, and then the soybeans are of ecological and agro­nomic adaptation to the lands. However, many factors concerning such an adaptation still remain to be clarified in further studies.

As mentioned previously, HOLMBERG (1955) stated that the soybeans in Sweden were favorably selected from the soybeans in japan, because the soybeans in japan have been selected in the insular climate similar to that in Sweden. He also noted the coincidence of the temperatures in the grow­ing seasons between japan and Sweden. Many data presented to date show the differences in the temperature and the rainfall between japan and the United States or Manchuria, and then the dif­ferences seem to contribute to the adaptations of the determinate and the indeterminate soybeans. The effects of the climates of the countries on the differentiation of soybeans will be considered in detail in other papers.

The chemical components of the materials, such as oil and protein, were analyzed in japan and the United States, though no data are pre­sented in this thesis, and Manchurian and American soybeans were h igh consistently in the oil contents. Among the japanese soybeans, the soybeans of Hokkaido have had the same contents of oil as those of American soybeans, but the soybeans from KyUshu were significantly low in the oil contents as shown already by some workers (AKIT ANI and MIYAZAKI 1949) . Perhaps, the oil content is not contributi ve to the differentiation of soybeans between Japan and the United States.

Thus, it is apparent that the soybeans of eco­type manchuriensis are adaptable to the cultivation in the United States, especially in the northern part. from the agronomic and ecological view points. And then the determinate soybeans of ecotype japonicus borealis seem to be of less value for breeding the commercial soybeans but the vege­table soybeans in the country. The soybeans of japonicus australis may be of possible value for the cultivation of soybeans as a very short season crop in the southern part of the United States, though such a cultivation has not been practiced in the part.

XII, 1960 Series: Agriculture

SUMMARY AND CONCLUSION

In order to consider the agronomic significance of the ecotypic differentiation of soybeans in Japan and in the world. following series of researches were pursued during the years from 1950 to 1958:

ADAPTATION OF THE SUMMER VS. AUTUMN SOYBEAN TYPES TO THE PLANT­ING TIME IN RELATION TO THE FLOWERING AND FRUITING.

Flowering and fruiting of the summer vs. autumn soybean types Planted in a spaced rate and at the times of successive intervals throughout the growing season. By using the representative varie­ties of the summer vs. autumn soybean types, the factors concerning the adaptation to the planting time were investigated.

i. The seed yield of the summer soybean type was high in April planting whereas that of the autumn soybean type was fair in a later planting than in April. Among the components of the yields, the number of flowers varied in parallel with the seed weight per plant in succesive plant­ings, and the percentage of pods to flowers and the seed size had no significant relation to the variation of the seed weight due to the planting time.

ii. The behavior of the flowering process ap­peared to have a notable bearing on the adaptation to the planting time. The moderate duration of flowering (approximately 25 days) and abundant flowers per day were found in the summer soy­bean type planted in April and in the autumn soy­bean type . planted in June. The autumn soybean type planted in April showed a very long duration of flowering, but its number of flowers per day was less than that planted in June.

Thus, the factor controlling the behavior of flowering became of interest for the study of the subject.

Effect of the daYlength after the flower pri­mordia initaition on the flowering process of the autumn soybean type. In the experiment, Akazaya Shirodaizu soybean was planted on May 5 (1954) and April 25 (1955), and grown under the con­trolled 9·hour daylength during the periods from following days to the maturity: 17 days prior to flowering, 7 days prior to flowering (1954), 5 days prior to flowering, the beginning of flowering, and 10 days after flowering (1955). The results ob­tained from the comparisons among the above day· length treatments and control (natural daylength) showed that the short day after flower primordia initiation shortened the flowering period and in' creased the flowers per day. and that the effect was the most obvious in the plots starting the

120

short-day treatment during the period from a week prior to flowering to the beginning of flowering, and less in the other plots treated too early or too late.

Such a result was considered in comparison with the performance of successive planting ex­periments as follows: the plots treated during the period from a week prior to flowering to the be­ginning of flowering correspond to June planting, namely the adaptable planting time. and the plots treated 10 days after the beginning of flowering and the plots treated 17 days prior to flowering correspond respectively to July planting and April planting, namely too late and too early plantings.

Consequently, it is concluded that the effect of the daylength after the flower primordia initiation is the essential factor conditioning the adaptation to the planting time of autumn soybean type.

Moreover, it should be emphasized that the autumn soybean type is obligated to be planted at the adaptable time, and the cultural practices and other techniques can not compensate at all for the yield decrease in the early planting.

AGRONOMIC CHARACTERISTICS OF THE SOYBEANS OF THE INDETERMINATE GROWTH HABIT.

Properties of American soybeans attributive to their indeterminate growth habit.

In order to consider the possible significance of the indeterminate growing soybeans in the cul­tivation and breeding, the first mention was made of the indeterminate soybeans grown in the United States.

i. Many varieties from the United States, 56 in total, were investigated in 1954 to 1955, and the maturity groups, official groupings of soybeans in the United States were observed to correspond to our summer vs. autumn soybean type in the follow· ing way: O- II to summer soybean type, TIl-V to intermediate type, and VI -\1Jll to autumn soybean type. The indeterminate American soybeans be· longing to our summer soybean type were also observed as those having the attributes of the special summer . soybean type or the special non' vining type, such as a long relative flowering period, a long relative growing period, many nodes after the flowering, and long stem.

ii. Among the three groups classified on the basis of utilization, the forage and the vegetable group each include the indeterminate and the determinate growing soybeans, respectively. The commercial group was divided into two groups, namely, one. the indeterminate growth and early or medium early maturity for the most part, and

Sci. Rep. Hyogo Univ. Agric. Vol. 4, No.2

the other, the determinate growth and late maturi­ty mostly.

The consideration on the native lands of tested soybeans coincided exactly with the view of the g~necological differentiation of soybeans in the world presented by the author. As the result of the above consideration, the Japanese soybeans of the summer soybean type were found to be of no value for the commercial cultivation but the cul­tivation for the vegetables in the United States at present.

A supposed reason for cultivating the indeter­minate growing soybeans in the tropics. Many soybeans from the tropical Asia were tested under the short daylength in 1956 and 1957.

The stem length of the indeterminate soybeans was significantly higher than that of the determi­nate ones. The seed yield or number of pods were also observed to be superior in the indeter­minate soybeans to those in the determinates.

Such advantages of the growth and yield of the indeterminate soybeans were considered to be adaptable for the climate of the tropics, where the day length is consistently short, because the basic vegetative period under the short daylength was not differentiated in the soybeans so significantly as in the paddies.

Some genetic associations between the deter­minate vs. indeterminate growth habit and other agronomic characters. In the F2 and F3 genera­tions of the three crosses of soybeans, stem length, seed yields and seed sizes were surveyed.

i. The stem length associated significantly with the determinate vs. indeterminate growth habit, and then the indeterminate growing plants or families were about 20-30 em taller than the deter­minate ones.

ii. The seed yield was low in the heritablity succeeding to those crosses, and the association of the seed yield was not so apparent as that of stem length. However, the difference in the seed yields between the determinate and the indeterminate plants or families of early maturity was found, and the indeterminate ones were of higher yield than ·the determinates. Such a difference was not found in the late matured soybeans.

iii. The seed size did not associate with the determinate vs. indeterminate growth habit.

Thus, the indeterminate soybeans seem to be useful for breeding taller soybeans, and the in­determinate soybeans of the summer soybean type or the intermediate type prevailing in the United States might be bred for such association of the habits. The high seed yield of the indeterminate soybeans of early or medium early maturity was also contributive to the breeding of the said soybeans

121

in the United States, and shall be useful for fur­ther improvements of soybeans at the future time. Finally, hence the seed size did not associate with the growth habit, the small seeded character of the indeterminate soybeans which are being grown in the world at present are supposed to have been resulted from other agronomic and ecological selec­tions. Thus the indeterminate soybeans of large seed shall be possible to be bred further.

REGIONAL ADAPTABILITIES OF PRINCI­PAL VARIETIES OF THE SUMMER SOYBEAN TYPE CUL TIV ATED IN DIFFERENT REGIONS.

Cooperative performances in Japan. Three representative varieties of each groups of soybeans cultivated in Hokkaido, KyUshu, Manchuria and the United States, 12 in total, were tested coopera­tively at Sapporo in Hokkaido, Sasayama in Hyogo and Nishigoshi in Kumamoto in KyushU, in 1955. Moreover, 33 representatives from all of the said regions or countries were investigated at the same locations in 1956.

i. The yield expressed by a seed weight per plant was affected by variety, location and year. In 1955, the indeterminate soybeans of Manchuria and the United States appeared to be of higher yield­ing than the determinate soybeans in Japan in the performance in Kumamoto, but did not appear so significantly in Hokkaido. While the superiorities of the indeterminate soybeans on the seed yield were emphasized in Hokkaido rather than in Kuma­moto and Hyogo, in 1956.

Between the soybeans cultivated in Hokkaido and Kyushu, KyushU soybeans were more yielding

_than the soybeans of Hokkaido in the test of Kumamoto, but such a difference was not sifinifi­cant in the test in Hokkaido, in 1955. Whereas, the soybeans of Kyushu showed considerably good yields at all locations of the tests in 1956 when compared with the soybeans of Hokkaido.

ii. The seed quality of soybeans harvested in Kumamoto and Hyogo was apparently fair in the soybeans from KyUshu exceeding the soybeans from other regions, namely Hokkaido, Manchuria and the United States.

iii. The correlations of the seed yields and other yield components behaved to associate with the variations of the seed yields mentioned above. In 1955, the seed yields correlated to the stem length in Kumamoto whereas to the characters of branching in Hokkaido at a highly significant level. Nevertheless, the stem length showed a significant correlation to the yield in the performances of both locations in 1956.

In general, the growths of soybeans of the short season crop in KyUshu were poor in com­parison with the soybeans cultivated as the full

XII, 1956 Series: Agriculture

season crop in Hokkaido. while the growth of the soybean plants in Hokkaido in 1956 was consider­ably poor by reason of the extremely cool summer. Consequently, the said correlations and yields of the materials mentioned above seem to be pointing out that the indeterminate soybeans are perhaps adaptable for the lands or environments of poor growth.

iv. From the above results, it was concluded that the indeterminate soybeans might be adapta­ble to the lands or cultural conditions of poor growth in South Japan and others, but the inferior seed quality of the said soybeans should be im­proved by the selections. Moreover, it is said that the soybeans of KyUshu seem to be adaptable for the cultivation of the short season crop in South Japan with respect to their seed yields and seed qualities.

Cooperative performances in the United States. For the purpose of considering the problems of adaptabilites of soybeans in the United States in comparison with those in Japan, cooperative tests were carried out at Urbana, Illinois, and Stoneville, Mississippi. in 1956, 1957, and 1958, by using the same varieties as those in cooperative tests in Japan.

i. The seed yields of the indeterminate soy­beans of Manchuria and the United States were significantly higher than those of the determinate soybeans of Japan in the tests of two years in Illinois, and then the seed yields of the indetermi­nate soybeans were the same as those of the deter-

minate soybeans maturing about 10 to 30 days later. In the test of 1958 in Mississippi, KyUshU soybeans of the determinate growth showed higher yield than Hokkaido soybeans of the same habit.

In addition to the seed yield, the shattering percentage was observed to be less in the indeter­minate soybeans than in ~he determinate soybeans apparently.

ii. The correlation of the seed yields to the stem lengths was highly significant in the perfor­mances. The stems of soybeans grown in Illinois, however, were fairly high in comparison with those in KyUshu, and similar to those in Hokkaido in 1955. Consequently, the superiority of the yield of the indeterminate soybeans were considered to be not attributing to the poor growth noted in Kyushu, but perhaps to other factors such as a solid planting.

From the results mentioned above, it was con­cluded that the indeterminate soybeans of ecotype machuriensis were of ecological- and agronomic adaptation for the commercial cultivation in the north part of the United States, and the determi­nate soybeans in Japan were of no value for such cultivation but for the vegetable growing. The soybeans of ecotype japonicus australis seem to be useful for the cultivation of soybeans of the very short season crop in the south part of the United States in which the cultivation is not prac­ticed in the part at present.

(Received Aug. 30, 1960)

LITERATURE CITED

AKITANI, T., and MIYAZAKI, M.: Rpt. Food Res. . Ins!., Food Agency Dept. Agr. & For. 2: 83-

88, 1949. BARTLEY, B. G., and WEBER, C. R.: Agron. J.44:

487 -493, 1952. BORTHWICK, H. A., and PARKER, M. W.: Bot. Gaz.

101: 341-365, 1939. EGUCHI, T.: Proc. Imp. Acad. Japan. 13: 323-333,

1937. Sci. Rpt. Chiba Hort. Coli. 4, 1940.

FUKUI, J" and YARIMIZU, H.: Jap. J. Breed. 1: 86-90, 1951.

Proc. Crop. Sci. Soc. Jap. 21: 123-124, 1952.

GARNER,. W. W., and ALLARD, H. A.: f. Agr. Res. 18: 553-556, 1920.

HARTWIG, E. E.: U. S. D. A. Circ. 943, 1954. and LEHMAN, S. G.: Agron. J. 43: 226-

229, 1951. HOLMBERG, S. A.: Agr. & Hort. (Tokyo) 30:

1427-1430, 1955.

122

Jo, K.: Agr. & Hort. (Tokyo) 13; 1170-1194,1938. MAHMUD, 1., and KRAMMER, H. H.: Agron. J. 43:

605-609, 1951. MATSUO, T.: Bul. Nat. Inst. Agr. Sci. (Tokyo),

D-3: 1-112, 1952. MORSE, W. J., and CARTTER, J. L.: U. S. D. A.

Farm. Bul_ 1520, 1949. NAGATA, T.: Studies on the characteristics of soy­

bean varieties. Tokyo, 1950. Proc. Crop. Sci. Soc. Jap. 19: 279-282,

1951. Proc. Crop. Sci. Soc. Jap. 27: 87-90,

1958. Proc. Crop. Sci. Soc. Jap. 28; 79-82,

1959. Mem. Hyogo Univ. Agr. 3 (Agron.

Series): 63-102, 196Oa. Sci. Rpt. Hyogo Univ. Agr. 5 (Series

Agr.): 71-95, 1960b. PARKER, M. W. and BoRTHWICK, H. A.: Soybean

Digest, 11(11); 26-30, 1951.