Estimation of genetic variability and efficiency of selection for grain yield and its components in two wheat

SEMINAR PRESENTATION ON

ESTIMATION OF GENETIC VARIABILITY AND EFFICIENCY OF SELECTION FOR GRAIN YIELD AND ITS COMPONENTS IN TWO WHEAT CROSSES(Triticum aestivum L.)

Department of Genetics and Plant Breeding,Allahabad School of Agriculture,

Sam Higginbottom Institute of Agriculture, Technology & Sciences(Formerly Allahabad Agriculture Institute)

Deemed-to-be-UniversityAllahabad, UP

2016

PRESENTED BYNAVEEN JAKHAR

ID. No.-14MSCGPB029

Detail of research paper IntroductionObjectivesMaterials and methodsObservation were recordedStatistical analysisResults and discussionConclusionReferences

CONTENT

DETAIL OF RESEARCH PAPER

International Journal of Agriculture and Crop Sciences Volume 7, Issue 2, June 2014 ISSN 2227-670X Estimate of Genetic Variability and Efficiency of Selection for Grain yield and Its

Components in Two Wheat Crosses(Triticum aestivum L.) Published By- Mohamed A. Abd El-Shafi Agronomy Department Faculty of Agriculture, Cairo University, El-Gamma Street, P.O. Box

12613 Giza, Egypt.

INTRODUCTION

Wheat (Triticum aestivum L.) is the most important food crop of the world and ranks first among all the cereals.

Individual plant selection in early segregating generations for quantitatively inherited traits such as grain yield has met with limited success. This impedition may due to several factors such as polygenic nature, low heritability of a trait (grain yield, number of spike per plant, etc.) linkage, non–additive gene effects and environmental effects. The most frequent reason given for this failure in wheat include the inability to identify useable genetic variations and a large environment effect (Rezqui 1993)

In order to overcome these difficulties it is necessary to get as much as possible information about genetic structure of crosses under going selection. This mean identifying the gene effects that control the inheritance of a trait of interest and contributing to the exploitable genetic variance in the crosses.

Contd..The high heritability associated with high genetic advance for main quantitative

traits in wheat offer better scope of selection of genotypes in early segregating generations(Memon et al. 2005). The heritability of a character determines the extent to which it is transmitted from one generations to the next and it is most valuable tool when used in conjunction with other parameters in predicting genetic gain that follows in the selection for that character (Bloch et al. 2003, Ansari et al. 2004, 2005, El-Ameen et al. 2013)

Numerous methods have been proposed but only a few valid comparisons have been made among alternative procedures .Pedigree methods of selection are very common selection technique in self–pollinated crops.

This method represents the procedure where an individual plant is selected successively through generations(f 2 -fn) by monitoring selected offspring till homozygous lines.

Pedigree method has drawbacks due to high costs of record keeping, utilization of manpower, genetic drift and loss of desirable genes.

Verma et al.(1997) and El-Ameen et al. (2013) showed that pedigree method of selection was more effective in improving plant height and yield and its components.

Objective of the present research work was therefore conducted to study the relative response to selection in two bread wheat crosses for two cycles started in F2 using pedigree selection procedure for improving grain yield and its components

OBJECTIVE

Estimates the genetic variability and efficiency of selection for grain yield and its components in two wheat crosses.

MATERIALS AND METHODS

The present experiment was conducted over three seasons (2010-2011, 2011-2012 and 2012-2013) at Faculty of agriculture, Cairo University, Agriculture Experiment and Research Station, in Giza governorate, Egypt.

In 2010-2011Genotypes - 300 F2 plantsExperimental design -Randomized Block Design

(RBD)Replications - 02Row to raw distance -10cmPlant to plant distance -30cm.

In 2011-2012F3 progenies of selected f2 plants for each cross with there

parents were planted.Replication 2Rows length 1.30 mSpecing 30 X 10 In 2012-2013For each cross a sample of 48 families (a family is the

progeny of an individual f2 plant), each represented by two lines (a line is the progeny of an individual f3 plant)

Replication 3Single row plot 30 x 10

OBSERVATIONS WERE RECORDEDS.NO Observations

1 Plant height

2 Spike length

3 Spikelets per spike

4 No. of kernels per spike

5 No. of spikes per plant

6 Grain yield per plant

STATISTICAL ANALYSIS Data for each cross was considered a individually in the analysis of

variance . The data were statistically analyzed by MSTST-C V.2.1 (Russell 1994).

Heritability in broad sense(H)Broad sense heritability was estimated using the components of variation

according to the formulae outlined by Weber and Moorthy (1952) .Actual and predicted gainsIn a cycle 1 the predicted gains of F3 progenies were derived from

selected F2 lines were obtained by multiplying the differential between the F2 parental sample mean by the heritability percentage. The actual gain represented by differential between the progeny of the selected parents and F2 cross mean.

In cycle 2 the predicted gains of F4 progenies derived from selected F3 lines were obtained by multiplying differential between the F3 cross and parental sample means by the heritability percentage. The actual gain represented by the differential between the progeny of the selected parents and F4 cross mean.

Phenotypic (PCV%) and Genotypic (GCV%) coefficients of variations for the studied traits were calculated as described by Burton(1952).

RESULTS AND DISCUSSIONAnalysis of varianceResults of analysis of variance for the studied two crosses (L-39 x V92/17) and

(New valley x V92/17)are presented in table. These results revealed significant(p=0.05)and highly significant

(p=0.01)difference among genotypes (families + parents) and families for all studies traits across the three generations (F2, F3 & F4), except spikelets per spike.

Which exhibited no significance difference among families in f3 generations for cross 1 and 2. These finding indicates that a greater response to selection can be expected from these crosses.

Mean values Mean values of F2 plants , F3 and F4 lines selected for yield and its component

are shown in table. The difference between the high and low mean value relative to high mean value (R%). In the F2 generation ranged from 13.28% for spikelets per spike in the L-39 x V92/17 cross to 41.80% for grain yield per plant in the New valley x V92/17 cross to55.81% for grain yield per plant in the New valley x V92/17 cross.

Contd.. Mean while, in the F4 generations, the differences between the

high and low mean value relative to high mean value (R%) ranged from 13.62% for spikelets per spike in the L-39 X V92/17 cross to 70.03%for no. of spike per plant in the L-39 X V92/17 cross.

These % were higher for grain yield than for any yield component in all crosses in the F2 generation and in one of two crosses in the F3 generations .On the contrary , all of two crosses were lower for grain yield than for any yield components in the F4 generations .

The presence of the differences between high and low suggested that selection would be effective in these crosses .these crosses .These findings were in harmony with those obtained by Alexender et al (1984).

Pertinent analysis of variance of two crosses across three generations (F2, F3 and F4) for the studied traits.Plant Height

Cross 1 Seg. Gen. F2 F3 F4

L-39 Genotypes(g) 61.15 157.01 445.39

X Families(F) 57.86 155.53 431.75

V92/17 Parents(p) 1089.00 441.00 477.56

Cross 2 S.V. F2 F3 F4

New valley Genotypes(g) 26.05 142.17 703.63

X Families(F) 23.97 132.80 599.16

V92/17 Parents(p) 33.64 1089.00 519.91

Spike length


L-39 Genotypes(g) 0.88 0.85 5.83

X Families(F) 0.73 0.85 4.57

V92/17 Parents(p) 0.14 0.01 26.86



X Families(F) 0.39 2.21 3.09

V92/17 Parents(p) 0.28 0.30 10.37

Spikelets spike


L-39 Genotypes(g) 040 6.79 5.48

X Families(F) 0.35 1.39 1.52

V92/17 Parents(p) 1.44 11.56 11.51



X Families(F) 0.43 0.90 7.76

V92/17 Parents(p) 0.16 1.44 6.65

Kernels per spike


L-39 Genotypes(g) 25.86 98.96 5.85

X Families(F) 23.04 88.34 4.39

V92/17 Parents(p) 33.64 14.44 4.22



X Families(F) 28.07 40.65 168.77

V92/17 Parents(p) 5.76 33.64 312.51

No of spikes per spike


L-39 Genotypes(g) 12.74 8.39 0.68

X Families(F) 12.74 8.55 0.28

V92/17 Parents(p) 1.56 1.82 1.29



X Families(F) 4.15 4.57 67.1

V92/17 Parents(p) 1.32 3.06 76.5

Grain yield per plant


L-39 Genotypes(g) 61.13 72.78 21.79

X Families(F) 50.40 56.76 12.81

V92/17 Parents(p) 2.62 14.73 15.28



X Families(F) 12.34 49.62 16.22

V92/17 Parents(p) 0.01 0.79 30.94

Mean value of two crosses across three generations (F2, F3 and f4) for the studied traits L-39 xV92/17

F2 F3 F4

Traits F2 R% L-39

V92/17

F3 R% L-39 V92/17

F4 R% L-39 V92/17

Plant height

104.08

26.00

102.10

90.46

84.0 41.15 68.95 91.09 34.22 34.22 105.45

72.45

Spike length

11.85 15.07

11.58

12.89

9.49 9.38 9.62 12.01 33.87 33.87 8.24 8.80

Spikelets / spike

17.40 13.28

19.34

16.15

19.14 14.60 13.99 20.08 13.62 13.62 18.75

17.55

Kernals/ spike

46.29 17.99

55.29

40.15

64.36 52.18 37.49 63.03 34.81 34.81 51.10

45.30

No of spikes/plant

11.50 25.01

11.79

11.13

17.63 16.55 17.90 17.80 70.03 70.03 15.05

15.45

Grain yield /plant

14.21 37.73

19.13

10.18

40.10 17.84 18.18 50.56 57.06 57.06 20.97

21.86

New valley xV92/17

F2 F3 F4

Traits F2 R% NV V92/17

F3 R% NV V92/17

F4 R% NV V92/17

Plant height

101.79

30.91

104.84

90.46

86.21 40.98 108.82

68.95 90.83 32.73 92.45 72.45

Spike length

11.65

19.11

11.65

12.89

9.50 53.69 8.72 9.62 11.45 30.42 9.34 8.80

Spikelets / spike

18.42

17.56

19.55

16.15

19.26 19.66 14.10 13.99 21.00 20.30 17.95 17.55

Kernals/ spike

49.79

19.80

55.98

40.15

63.39 39.77 48.47 37.49 65.37 47.98 42.19 45.30

No of spikes/plant

11.46

34.49

11.76

11.13

14.16 47.52 15.45 17.90 16.09 57.91 12.65 15.45

Grain yield /plant

16.13

41.80

18.37

10.18

40.98 55.81 19.72 18.18 44.80 36.54 19.26 21.86

New valley xV92/17

F2 F3 F4

Traits F2 R% NV V92/17

F3 R% NV V92/17

F4 R% NV V92/17

Plant height

101.79

30.91

104.84

90.46

86.21 40.98 108.82

68.95 90.83 32.73 92.45 72.45

Spike length

11.65

19.11

11.65

12.89

9.50 53.69 8.72 9.62 11.45 30.42 9.34 8.80

Spikelets / spike

18.42

17.56

19.55

16.15

19.26 19.66 14.10 13.99 21.00 20.30 17.95 17.55

Kernals/ spike

49.79

19.80

55.98

40.15

63.39 39.77 48.47 37.49 65.37 47.98 42.19 45.30

No of spikes/plant

11.46

34.49

11.76

11.13

14.16 47.52 15.45 17.90 16.09 57.91 12.65 15.45

Grain yield /plant

16.13

41.80

18.37

10.18

40.98 55.81 19.72 18.18 44.80 36.54 19.26 21.86

VariabilityVariance is considered one of the most important factors for efficiency

of selection and breeding methods. Data of phenotypic variance , genotypic variance ,phenotypic coefficient of variation (PCV%), genotypic coefficient of variations (GCV%) and broad sense heritability are presented in table.

Results of plant height showed difference values of phenotypic, genotypic variance and variability of (PCV% & GCV%) according to crosses and generations. The small difference between PCV% and GCV%, confirming the importance of genetic components of variability controlling plant height rather then the environmental effects.

Broad sense heritability estimates for plant height were (52.41, 94.96 and 83.54) and (63.29, 96.98 and 88.86) for F2, F3 and F4 in the cross 1 and 2 respectively. These results indicate that plant height was less affected by environmental factors.

Contd..Results of variances and variability for spike length and spikelets /spike show that

less values were detected according to crosses and generations. Estimates of broad sense heritability for spike length varied from low percentage 37.07% in cross 1 and 2 for F2 generation to high percentage in F4 generation through the two crosses.Estimates of broad sense heritability for number of spikes /plant varied from intermediate in F2 and F3 generations to high in F4 generation across the two crosses . These results indicate that number of kernels /spike and number of spikes /plant were less affected by environmental factors and are controlled mainly by genetic system.Results of grain yield /plant revealed that the magnitude of phenotypic and genotypic variances were high variability. The variability of PCV% and GCV% has low percentages indicating decrease of variability. These results suggested that the directional selection appears to reduce the range and variability for grain yield /plant in the F4.

Difference between phenotypic, genotypic variances were low indicate that grain yield /plant were less affected by environmental factors and this is clearing in the high values of broad sense heritability for the two crosses especially in F4 generation.

For plant height the selection parental sample in the F2 of cross 1 was 1.93% higher than the cross mean, and was almost identical 1.89% with mean plant height of their progenies of the F3. However , the trend of the predicted (7.28%) was higher than the actual gains (4.90%)in cycle 2 from F3 and F4 generation. Meanwhile , for plant height in cross 2 they behavior were identical with cross 1. These results of close agreement between the expected and actual gains suggest that the gene action involved in cycle 1 and 2 is largely additive.

For spike length, spikelets / spike , kernels /spike and No. of spikes /plant the actual gain as percentage of cross mean was higher than the predicted one , through cycle 1 and 2 for the two crosses. These results confirming the predominance of dominance gene effects.

For grain yield /plant the actual gain as percentage of cross mean was higher than the predicted one, through cycle 1 and 2 for the two crosses. These results of highest values of actual than predicted indicate that dominance gene effects are involved in the inheritance of that trait.

Response to selection

CONCLUSION

From the results obtained in this work, it can be concluded that pedigree selection method was effective in improving the grain yield and its components . Also selection was effective to produce new lines with higher grain yield .

REFERENCES

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