GRAPE GENETICS AND GERMPLASM RESEARCH IN CALIFORNIA

Report of A Grape Germplasm Task Force

Carole P. Me~edith, Editor

Colkge of Agrioulturlal and f nwipnmeatol Scisncss Agrioultura! Experimgrrt Statisti ,

Univra~sity of Cqlif~rnia, h i s , Charles E; Heiss, ~ean'and'~sso<rlafa Qiractor

GRAFT GEXETICS AN0 GERQLASM RESEARCH IN CALImIWIA

Report of A Grape Germplasm Task Force

Carole P. Meredith, Eaitor

College of Ag-ricultural and Emiranmental Sciences Ag- r in i l t u r a l Expriment Station University of Califo?mia, Davis

(3arle.s E. Hess, Dean and Associate D i E & O r

December 1986

UNIVERSITY O F CALIFORNIA, DAVIS

BERPELEY . DAVIS . lRVINE . LOS ASCELES . RiVPISlDE ' IAN D I Z O . SAN PIUNClSCO SANTA BARBARA . SAATA CRLZ

COLLEGE OF AGRICULTURAL A N D

ENVIRONMENTAL SCIENCES

ACRICULTWPAL EXPEFUMENT STATION

OFFICE O F THE DEAN AND ASSOCTATE D-CTOR

DAVIS, CALIFORNIA 95616

January, 1987

Dear Fr iends :

I am pleased t o p resen t , f o r your review and comment, t h i s r epor t on "Grape Genetics and Germplasm Research i n Ca l i fo rn ia . " The mult i -faceted grape indus t ry i n C a l i f o r n i a i s v i t a l to t h e economic h e a l t h of t h i s s t a t e . Along with new problems t o be faced t h e r e a r e new oppor tun i t i e s to be pursued t h a t w i l l s u s t a i n and improve t h i s indus t ry . Grape germplasm provides t h e foundation f o r a v i a b l e indus t ry .

We a r e pleased t h a t more than one hundred years of research and development work by t h e research s t a f f of the Ca l i fo rn ia Agr icu l tu ra l Experiment S t a t i o n and our pa r tne r s i n t h e U.S.D.A. Agr icu l tu ra l Research Service have gener- a t e d important f ind ings and m a t e r i a l s f o r t h e Ca l i fo rn ia grape indus t ry . A s we look ahead, we f ind t h a t s e v e r a l key Univers i ty of C a l i f o r n i a and USDA s c i e n t i s t s have r e c e n t l y completed, o r a r e nearing completion of t h e i r p ro fess iona l c a r e e r s . I t i s e s s e n t i a l t h a t we now a s s e s s t h e c a p a b i l i t i e s and needs f o r continued research on grape gene t i c s and germplasm.

One of t h e f i n e s t c o l l e c t i o n s of world grape germplasm was assembled a t UC Davis by Professor Harold P . Olmo and h i s predecessors.. These m a t e r i a l s have been the b a s i s both f o r new v a r i e t i e s and f o r va luable information about t h e growth, evolu t ion , and use of grapes. The f u t u r e management and e x p l o i t a t i o n of these genet ic resources warrants c a r e f u l cons ide ra t ion . New developments i n gene t i c s make i t f e a s i b l e to approach t h e t r a n s f e r of genes from wild and unadapted grapevines i n ways not considered p o s s i b l e 10 years ago. Perpetua l maintenance of grape gene t i c s tocks , a gene-bank f o r t h e f u t u r e , i s e s s e n t i a l and must be addressed by publ ic agencies such a s t h e Unive r s i ty of Ca l i fo rn ia .

I n March 1985 I inv i t ed a t a s k f o r c e t o consider the c u r r e n t s i t u a t i o n and t h e f u t u r e f o r grape germplasm research . This group undertook i t s assign- ment wi th enthusiasm and produced an e x c e l l e n t r epor t which I hope you w i l l review i n d e t a i l . We in tend t o implement t h e recommendations, i n f u l l o r p a r t , a s personnel and f i s c a l resources become ava i l ab le . Your comments w i l l be c a r e f u l l y considered.

S incere ly , )?

Q&?.w Char e s E. Hess Dean and Associate Di rec to r

CEH : vz

TABLE OF CO-

PREFACE 1

MEMBERS OF THE TASK FORCE 2

E X E m SUMMARY 3

PEST AND DISEASE MANAGDIEKT Nmatcdes Insects and mites Fungal diseases Bacterial diseases Virus diseases

CROP MANAGEDmn Water relations Mineral nutrition Tempratme extremes G r a J t h and dwelopent

UTI~ZATION Table grapes Raisin grapes W i n e grapes

GENETIC RESOURCES AND mLS ~ermp~asm resources Conventional breeding Fvdanental genetics New genetic technolcqy

RESEARCH NEECG 27

CJFCCNF GENETICS AND GERMPLASM RFSEARCH 29

RESEARCH PLAN 32

APPENDIX I. 37 Major grape prduction problems in California

APPENDIX 11. 44 Current grape researchers in California, including University of California faculty, UC Cooperative Extension specialists, and U.S. D e p r t m n t of Agriculture scientists .

This report was developed over a period of several months by the conscientious efforts of the Task Force named on the following page. Considerable assistance was also provided by A. M. Dandekar (Pom31cq-y D e w t , UC Davis), K. S. Moulton (Cwperative Ektension, UC Berkeley) and L. T. Wilson (htomslqy Departrrwrt, UC Eavis). Special gratitude is extended to Dr. Carole P. ~eredith, who edited the whole report and contributed substantially to several sections. Travel and other expenses were partially met through a grant prwided by the California Department of F d and Agriculture for analysis of genetic resources in California. Roberta Silver, Secretary in the I)eants Office and later Administrative Assistant for the UC Genetic R e s o m Conservation Prcyram, prwided logistical support throughout the review pricd.

'Ihe report was completed in June 1986 and, after internal review, was revised for publication in Cecember 1986. ?he revision did not alter the in conclusions of the Task Force, but included an update of production statistics and personnel assigments and minor editorial impmvements.

Calvin 0. Qualset Chairman, Grape Germplasm Task Force and Director, UC Genetic Resources Conservation Frcyram

MEMBERS OF THE TASK FORCE

R. B. Boulton, Department of Viticulture and holcgy, UC Davis L. P. Qlristensen, Cooperative Extension, UC Keamey Agricultural

Center, Farlier H. Ferris, Division of Nematolcgy, UC Davis P. K. F'reese, Robert Mohvi Winery, Oakville A. C. Goheen, U.S. Deprbmt of Agriculture, Department of Plant

Fatholcgy, UC Davis J. Gmett, Department of htamolcgy, UC Davis W. M. Kliewer, Deprtmmt of Viticulture and Eholcgy, UC Davis L. A. Lider, Department of Viticulture and Enolcgy, UC Davis J. M. Lyons, Integrated Pest Management Implementation Group, UC

Davis J. J. Marois, Department of Plant Fatholcgy, UC hvis M. A. Wtthews, Department of Viticulture and holqy, UC Davis M. V. McKenry, UC Kearney Agricultural Center, Parlier - C. P. Meredith, Deprbmt of Viticulture and Enolcgy, UC Davis H. P. O W , Department of Viticulture and holcgy, UC Davis C. S. Ough, Deparhnent of Viticulture and Enolqy, UC Davis D. E. m i t t , National Clonal Germplasm Repository, UC Davis C. 0. -set, College of Agricultural ard Enviromtal Sciences,

UC Davis D. FLmmirq, U.S. Department of Agriculture, Fresno D. J. Raski, Division of Nematolcgy, UC Davis B. Ray, Foundation Seed and Plant Materials Service, UC Davis R. K. Scost, Department of Botany and Plant Sciences, UC Riverside L. E. Williams, Department of Viticulture and Enolqy, UC Kearney

Agricultural Center, Parlier J. A. Wolpert, Cooperative Extension, Deprtmmt of Viticulture and

Enolqy, UC Davis

D(ECUTIVE SUMMARY

Grape production is a critical component of California's econamy. The future economic health of this industry will depend on the ability of gmwers to maximize both production efficiency and fruit quality. Research in grape genetics and germplasm can make a significant contribution to both objectives, both through the development of improved cultivars and by the use of genetic tools to understand how grapevines respond to enviromtal and management factors. Important new research opportunities are emerging and must be exploited if the California grape industry is to derive the N 1 benefits of genetic research.

Genetic resistance can potentially be used to control many pests and diseases that limit grape production and quality. Resistance represents a more p?nment, less expnsive, and ecologically more sound strategy than chemical control. Research is needed to identify sources of resistance in grape germplasm and to understand the mechanisms by mich some grapes (or grape relatives) may withstand a pest or pathogen. This informtion will facilitate the development of resistant cultivars, clones, and rootstocks, by either conventional plant breeding methcds or by new genetic technolcgy, khichever is the most expedient approach for each particular problem. Genetic research can also be used to better adapt grape production to particular enviromtal conditions. Comparative studies of grape cultivars and grape relatives can lead to the development of genetically inpmved types that are more resistant to adverse environmental conditions such as frost, drought, or poor soil. Such research m y also provide information that will result in improved mag-t practices for such sites. A great deal of potential also exists for genetically modifying the very shape of the vine (such as is now done by trellising, training, and pruning) to maximize fruit quality and control diseases and pests.

California grapes are used primarily for fresh consuption, for raisins, and for wine. Each use is asscciated with particular needs that can be addressed by genetic r-ch. The size, color, and season of table grapes can be modified genetically. Inproved raisin cultivars that mature earlier and can be mechanically harvested might be prcduced through genetic research. In wine grapes, flavor, stability, and fermentation characteristics are also amenable to genetic manipulation, but a great deal of research is necessary to understand the genetic control of grape composition.

Essential to the application of genetic research to the needs of California grape producers is an arsenal of genetic resources and twls that can be called upon as needed. The extensive germplasm collections of grape cultivars and wild relatives already established at UC Davis must be further strengthened, mintained, and studied. The fundmental genetic IMkeup of grapevines must be elucidated. Effective genetic technologies, including conventional

plant breeding as well as new cellular and molecular genetic techniques, rrmst be developed and refined so that they can be used to manipulate important traits.

University of California faculty, UC Cooperative Dctewion reseamhers, and U.S. Department of Agriculhrre scientists in a n h of disciplines and at severdl campuses and research stations contribute to grape research in California. Hwever, the genetics and gemplasm wmponent of this research is disproportionately ma11 campared to other research areas and is inadequate to meet research needs. The following recammendations are mde to remedy this situation:

D =ch in grape genetics and breeding must be further m=l.

An additional full position is needed in the area of conventional grape breeding and genetics to evaluate germplasm resources and incorporate them into new cultivars and rwtstocks.

m A partial position is required in grape molecular biolcgy to fully exploit the growing opportunities in this area, both to supplement existing research in cellular and molecular genetics and to unravel the basic - biolqical precesses that underlie important grapevine characteristics.

Increased research effort is needed in the pest and disease management disciplines affiliated with grape genetics.

The strong contribution of the U.S. Deparhnent of Agriculture in grape virolqy must be maintained.

D Natcde taxonomy research must be continued.

D New research activity is needed in the molecular biology of nematcde and insect pests that affect grapevines.

Additional plant patholcqy support must be provided to insure that the importation, indexing, and release of new grape mterial to California and other states will continue.

This augmented research effort will insure that genetic solutions to California grape prcduction problems will be effectively pursued.

rap prcduction plays a key role in the economy of California. Not only are grapes first in value and acreage among fmit crops prcduced in the state, but when all the many crops produced in California are considered, grape is surpassed in value only by cotton (Table 1). The annual farm gate value of the grape mop has been around 1 billion dollars over the last few years (out of a total of 14 billion dollars for d l aqriadtural pduction in the state). When the added value of processed grape products (e.g. wine, raisins) is taken into account, it is clear that the impact of grape prrduction on California agriculture is tremendous. Despite the mgnitude of the industry, it has not prospered recently. Grape production has incr& significantly over the last 10 years (Figure I), but market demand for grape prcducts has not. Anticipated inaeases in domestic wine consuption have not materialized. The strong dollar has increased the attractiveness of imps- wines and they have taken an increasingly large share of the wine market in recent years. Likewise, raisins pduced in other parts of the world are now claiming a larger share of the world raisin -kt, at the expense of California raisins. The oversuply of grapes and grape products, along with a general agricultural recession, has led to declining grape prices in all grape classes-wine, raisin, and table grapes (Figure 2). In same - cases, prices are not suificiently high to even cover the costs of prduction. Some vineyards, especially in the San Jcaquin Valley, are being removed or abandoned &ile others are now owned by banks. While the econdc problems associated with grape prcduction are not unique to California, they are vastly more significant here than in other states since over 90% of U.S. grapes are produced in California (Table 2).

Table 1. Value of California grape prcduction conpared to total California agricultural production.

State Total cash % of -P

Year Grapes farm receipts total ranking (x $1000) (x $1000)

* Cotton was the most valuable crop in these years (Source: California kpartment of Fccd and Agriculture)

FRESH

# RAISINS

CRUSHED

Ficnlre 1. California grape prcduction, by use categcry, 1975-1985. - (Source: California Dep%hent of Food and Agriculture)

YEAR

Figure 2. Returns to growers, 1975-1984. Adjusted to 1977 constant dollars by USDA cost-of-pra3uction index. (Source: California Department of Food and Agriculture; U.S. D e p r b e n t of Agriculture Statistical Reporting service)

Although growers can do little to affect the marketplace, they do have xlme degree of control over other factors that might improve their economic condition-production costs and crop quality. Increased efficiency of prduction can be achieved by reducing the costs of inputs (e.g. pesticides, fertilizers, frost protection) needed to prakce a crop. Fruit quality is becoming an increasingly important factor, particularly in the wineindustry. A grower who consistently produces high quality fruit is likely to obtain a higher price for the crop; but growers do not yet how how to control fruit quality. Both of these factors, increased production efficiency and bpruved fruit quality, can be addressed by research in grape genetics, both in the development of improved cultivars and by using genetic tmls to understand better how grapevines respond to environmental and management factors. An emerqing array of powerful new genetic t d q u e s is n w adding to the existing and already proven streqth of conventional plant genetics to create new opportunities for genetic research. But will these opportunities be pursued? Are the current research programs in grape genetics in California adequate to address the pressing needs of the California grape industry to the fullest extent now possible by new and established genetic technolcgy? These are the questions addressed here. The specific objectives of this report are :

1) To identify current or anticipated problems in the production, utilization, and marketing of grapes and grape prducts and indicate the solutions to these problems in wkich genetics and genrplasm research is an integral camponent.

2) To evaluate the extent and nature of the current gemplasm research in California.

3) To develop a research plan for meeting the long-term genetics d germplasm research needs for California, including the introduction of foreign germplasm, the evaluation of germplasm, the dozumentation of germplasm attributes and origins, selection of hproved stocks through various breeding pmzeAres, and basic genetic reseKch needed on grapes.

Table 2. 1984 United States grape prduction, by state.

State 1,000 tons % of t o t a l

Arizona Arkansas Gecrgia Michigan Missouri New York North Carolina Ohio Pennsylvania South Carolina Washington Other states

U.S. to ta l 5,582

Source: U.S. Department of A g r i c u l t u r e Statistical Reporting Semice

CURRENT PRODCTCI'ION PROBLEElS

1. PEST AND DISEASE MANA-

A wide range of pests and pathogens affect grape production. Although biologically diverse, these problems are conceptually similar w i t h regard t o the role of genetic research in their solutions. The chemical and cultural practices tha t m y be used t o control these problems are expensive and, i n the case of the former, t he i r use is increasingly restricted by eco lq ica l considerations and governmntal regulation. Host plant resistance is a form of pest and disease magement tha t is both economical, ecologically sound and relatively pmanent . R e s i s t a n t planting stock need only be purchased once, as opposed t o repeated applications of pesticides o r cultural practices.

The development of resistant cultivars has several essential cumpnents, whether the problem is an insect, nerrratcde, fungus, bacterium, or virus. A source of resistance must be identified, either in existing genrrplasn or through the generation of new genetic variability. Before the resistance can be exploited, its nature and genetic behzvior must be elucidated. The resistance n u s t then be incorporated into acceptable cultivars and, f inally, the

resistant cultivar must be evaluated under vineyard conditions. In addition to their use in the developrent of resistant

cultivars, sources of resistant germplasm play a key role in elucidating the fundamental mechanisms involved in host-parasite interactions. Comparative studies of resistant and susceptible genotypes can provide insights into potential resistance mechanisms and suggest rcdifications in management practices that might reduce crop losses.

Some of the major pest and disease problems affecting grape pnduction in California will be described here. For same, genetic strategies are already used in their management while for others they are only envisioned.

Nem3tcdes

While there are many different kinds of nematode parasites of grape, the most important are the rcot?u-iot nematcdes, Meloidme spp. ; the dagger nematodes, Xiphinema and 21, americanum; the lesion nematodes, Frat~lenchus spp.; the citrus nematode, ~lenchulus semipnetrans; and a nw$er of ectoparasitic Species such as the ring nematode, Criconemella xenoplax. Xi~hinema index is found principally in the coastal regions whereas the others are concentrated in the San Joaquin and Coachella Valleys. _X. =ex is not a very common nematode but it has become a major problem, - primarily because it is the vector for grapevine fanleaf virus, the cause of a devastating disease.

Nematode control has become an increasingly important problem in California in recent years. The most widely used chemical control, 1,2-dibr-3-dichloropropane (Dm), can no longer be used and gmwers must now rely more on pre-plant fumigants and resistant rootstocks .

While there are rcotstock cultivars that provide a degree of protection against same of these nematodes, certain problems are associated with their use, such as difficulty in propagation and excess vigor and delayed maturity in the scion. The development of new rootstocks with better horticultural characteristics and with even greater resistance against a wider range of nematodes is needed but is a slow and difficult prccess. Even in genotypes hown to be resistant to specific nematode types, the nature of resistance is poorly understood. Consequently, efforts to develop new rootstocks must rely on empirical screening of large populations of plants by inoculating them with the nematcde in question, a slow and expensive procedure. More sophisticated genetic mipulations are not possible because the specific morpholqical, physiolqical, or biochemical traits sought are unknown. An additional difficulty lies in the genetic diversity of the nematode species. Some of the nematode species have several races, each of which may have a different host range or degree of pathqenicity. The distribution of these various races is largely unknown due to the great difficulty in identifying them and thus the specific type of resistance needed for a particular production area m y be unknown.

Other than rootstocks, there m y be other biolqical strategies

for controlling nematodes on grapes. Biological control might be possible if neratc.de antagonists can be identified through the importation and. screening of exotic organisms and genetically manipulated to improve their adaptation and competitive abilities: If the specific mechanisms responsible for resistance in nematcde-resistant grape species can be elucidated, and the genes governing them identified, it is possible that resistance may eventually be introduced into scion varieties, thus eliminating the need for neratcde-resistant rootstocks. Not only would the elimination of rootstocks reduce the cost of prduction by elbinatkg grafting expenses, but it could also reduce the spread of graft-msible diseases.

Insects and mites

Phylloxera, a root parasite is a widespread insect pest on grapevines. In affected areas, grafting to phylloxera-resistant rootstocks is essential. Although this pest is, for the most part, adequately controlled by the existing resistant rwtstccks, it is likely that additional efforts will be needed in this area. While phylloxera is prkily associated with the grape growing regions of the North Coast and the Northern San Joaquin Valley, in recent years it has been found in the Salinas Valley and will likely became ixreasingly widespread. In addition, there is growing evidence - that there is n m more than one type of phylloxera in California. The new type is more virulent than the other and requires a greater degree of resistance in the rwtstcck. A continuing effort will be required to provide improved rwtstocks suitable for use in a variety of growing regions and with sufficient resistance to afford protection against all biotypes of the insect.

As is the case with nemt03.e resistance, little is knom about the fwdamntal mechanisms underlying phylloxera resistance and thus the developrent of new rwtstccks must rely on slaw and. expensive screening. A number of wild American grape species are highly resistant to phylloxera and studies of this germplasm could reveal the nature of the resistance mechanisms. As with neratcde resistance, it m y ulthtely be possible to intrcduce phylloxera resistance into scion varieties if the specific mdmnisms required can be identified.

'Itro leafhoppers, the grape leafhopper and the variegated leafhopper, are serious problms. While the grape leafhopper is more widespread, it is usually controlled by existing natural enemies. The variegated leafhopper is found mostly in the Southern San Joaquin Valley and desert. Since it is not controlled naturally, chemical controls are used, with undesirable consequences. Not only is there evidence that pesticide resistance is developing in both the variegated and grape leafhoppers, but the pesticides used are disrupting the natural enemies that would otherwise keep other pests under control. While host plant resistance to leafhoppers has not yet been studied in grapes, such resistance is knom in other crops and thus m y well be discovered among the genetic resources of domestic and wild grapes.

Several lepidopterous insects are significant grape pests. The mivorous leafroller (OLR) is widely distributed, although the severity of its effects varies f m year to year. This insect infests grape clusters and promotes secondary infections in the. fruit. Chemicals used to control the variegated leafnopper may be disrupting the natural enemies of OIR. An opportunity for the development of host plant resistance to OIR may be found by exploiting genetic differences in fnLt cluster structure. OIR damge appears to be most severe in tight clusters--the close proximity of the berries may facilitate the insect's feeding behavior. The development of clones with lcoser clusters might thus reduce losses to OIR. Orange tortrix behaves similarly to OIR and might be controlled in the same way. Grape leaf skeletonizer is a lepidopterous pest found mainly in the San J~dquin Valley and the lower desert. It has kkxme a mre severe problem recently in the San Joaquin Valley as a result of the depressed economic conditions there. While this insect is easy to control, many vineyards are being neglected by financially stressed growers and skeletonizer ppvlations are building up. ?he large populations in the neglected vineyards are thus significant sources of infestation for murding vineyards. A virus pathogen of grapeleaf skeletonizer may becOme an important means of control. The potential for developing host plant resistance to this insect is currently under investigation.

Spider mites are found in most California vineyards. The Pacific spider mite is more prevalent in warmer regions while the Willamette spider mite is found in cooler areas (and is thus asscciated more with coastal wine grape vineyards). Pacific spider mite populations have been increasing recently, possibly because of the disruption of natural enemies by pesticides used to control variegated leafhoppers. Mites are controlled by sulfur applications, but the use of sulfur for powdery mildew control has declined with the advent of new fungicides (e.g. Bayleton). Other chemicals (e.g. Omite) will control mites but also kill the predaceous mites that are the natural enemies of the mite pests. Based on evidence in other crops, host plant resistance to mites might be developed in grapes. No work has yet been done in this area, although some varietal differences have keen observed.

Until recently, grape mealybug has been considered only a minor problem, although it was once a serious pest on table grapes. Hwever, table grape qruwers are once again becoming seriously concerned about this insect. Chemical control is limited because of a waxy secretion that prevents pesticides from reaching this insect's cuticle. Eased on work with other crop species, both biological control by natural enemies and host plant resistance are potential control strategies that might be effective on grape meal ybugs . m a 1 diseases

Powdery mildew, caused by Uncinula necator, is the most widespread disease on grapes in California. The dry, mild climate

is ideal for its developt and spread. The cost of controlling this disease is extremely hi*: control and yield loss costs have been esthted to equal 10% of the entire California grape crop value. The degree of cultivar susceptibility varies tremendously, with Cariqnane, Thompson Seedless, Cardinal, Chardonnay, Cabernet Sawignon and Chenin blanc being the most susceptible, mile Petite Sirah, Zinfandel, Sdllon, and White Riesling are the most resistant. Although this genetic variability is well-bm its basis is not understccd and thus cannot be l~nipulated effectively in a genetic ~rovement prcgram. The fungus is an obligate parasite, requiring an intimate association with living tissue of the host for its growth. It is likely that this close interaction can be disrupted through genetic dpulation; this has already been accomplished in other craps where pa*dery mildew is a problem. Based upon research with other crops, there is reason to expect that resistance to pw3ery mildew m y be under simple genetic control and thus it m y eventually be possible to intrcduce a single gene for resistance into existing grape cultivars.

Botrytis bunch rot, caused by Botmtis cinerea, is another serious disease on grapes, especially in the coastal areas or ktm-~ rains ccax during the growing season. In 1976, losses reached 40% in same areas, although it usually ranges from 1 to 10% statewide. As with pw3ery mildew, there are varietal differences in susceptibility, with the thin-skinned, tight-clustered mite - varieties, such as White Riesling and Chenin blanc, being the mst severely affected. Unlike the pawaery mildew pathogen, this fungus is a saprophyte and can therefore survive on dead or livirg tissue of most plant rnatter. The spores require free water for germination and the microclimate of the leaf canopy may have a significant effect on the developrent of disease. Thus, in addition to the genetic manipulation of resistance to the pathogen, control m y be achieved through cultural practices that result in the appropriate canopy structure or even throw genetic dpulation of vine architecture such as the development of cultivars with longer internodes or looser clusters.

Eutypa dieback, caused by EutvDa armeniacae, is a widespread canker disease, especially in the higher rainfall districts. It is controlled mainly by prevention-fresh pruning wounds are painted with a fungicide. There is no economically sound control for already affected vines. Rarmving diseased portions of the vine is labor intensive and does not guarantee elimination of the pathogen. Eecause cultivar differences in susceptibility have been observed, host plant r-istance m y be a potential control strategy for this disease.

Fhompsis cane and leaf spat, caused by Phomorssis viticola, is also more prevalent in the higher rainfall areas. It is currently controlled with d o m t sprays or with fungicide applications after budbreak. Cultivar differences in susceptibility have also been observed with this disease, so resistance m y be a future means of control.

Measles is found on grapes throughout California, although it is more prevalent in the wazmer areas of the San Joaquin Valley and

generally affects older plantings. While the cause of this disease is not krmm, it is suspected to be a vascular fungus. There is no major research effort on this disease nor is there an effective control.

Bacterial diseases

Pierce's disease is the most serious bacterial disease affecting grapes in California. The disease is lccalized in "hot spots1', but these hot spots may be found throughout the state. It is a particularly serious problem in parts of Nap and Sonoma Counties, with scrme of the most valuable vineyard land in the state being affected. This disease kills infected vines and they must inevitably be m e d . There is no effective control, although the disease can be sonewhat restricted by controlling the insects that vector the pathcgen and the weeds that are alternate hosts. However, these maswes are neither effective or econcmically acceptable; they are only used because there is no alternative.

While vinifera cultivars differ sm-t in their tolerance to the disease, all cultivars are affected. Several wild -s species are resistant to Pierce's disease, but the mechanisrrr; of resistance are unknown. Even the disease itself is not well-understccd; it is not yet known how the pathcyen injures the vine. A better und- of the disease process might suggest cultural practices that could reduce the injury to the vines. While conventional breeding might be used to intrduce resistance to vinifera cultivars from wild American m s species, doing so would greatly dilute the vinifera fruit quality that is essential to the California industry. Alternative genetic strategies to develop resistant vinifera cultivars require that both the nature of resistance in the wild species and the nature of the interaction between the bacterium and vinifera vines be better understood. It may eventually be possible to develop resistant forms of vinifera &ti- by the selection of mutant cells if the specific mcteristic(s) necessary to prevent the development of disease could be deduced. If studies with resistant species reveal that only one or a few genes control the resistance (as is often the case with disease resistance) it may also be possible to intrcduce genes for resistance from these species to vinifera cultivars.

CYmm gall, caused by Ambacterim tumefaciens, is another bacterial disease that is important not so much in California vine- as in nurjeries, where the young cuttings are highly susceptible. The bacterium requires wounds for penetration and these are widespread in nurseries from cutting, grafting, transplanting, root trirmning, and budding. The bacterium lives in close asscciation with the host and actually transfers genes to the host. This feature of the bacterium is of particular interest in that it may be exploited as a means for introduciq new genes into grape cultivars (see Genetic Resources and Tools, New Genetic Technology).

Virus diseases

Viruses are generally not life-threatening to grapevines but they do cause severe diseases that reduce yield and fruit quality. They are spread primrily by clonal propagation (cuttings, budding, grafting) although they may also spread by other means. They are often latent in the qrape host, causing no visible disease reaction until they spread into a nonresistant scion or rootstock through grafting. It is the practice of grafting to phylloxera-resistant rootstocks that is largely responsible for the establishment of virus diseases in California grapevines. Although several virus diseases of grapevines are present in California, two are of major hprtan-leafroll, whose causal agent has not yet been identified, and infectious degeneration, caused by grapevine fanleaf virus. Leafroll has been eliminated from most important cultivars through the clean stcck pngram but infectious degeneration continues to be a serious problem because it is spread by a nematde - . - vector (Xi~hineIM -) .

Graw crernwlasm research affects the control of virus diseases - - in me& ways. Sources of resistance may be identified from surveys of germplasm, both wild and cultivated fom. Such resistant types may then be used in breeding programs to incorporate resistance into important rootstock or scion varieties. Hwever, the incorporation of resistance from wild species into scion - varieties has the same drawback as described above for Pierce's Disease-the redudion of f?dt quality. Incopration of resistance into rootstocks is useful in cases where transmission is primarily through the soil, as is the case with infectious degeneration. The identification of gennplasm accessions that are resistant to a virus disease also p d t s the nature of the resistance to be studied. Understanding the nature of resistance may suggest additional genetic control strategies or lead to ranagerent practices to reduce disease losses.

The intrcduction of new gennplasm into California from other places can be a source of disease. While the intrmhction of new germplasm is essential for continued progress it is essential that it be free of h a w n disease before being released. Thus the existing quarantine, ind*, and clean stcck distribution prcgrams are crucial to the control of virus diseases. It is also imp3rtant that collections of virus-infected plant material be maintained (under quarantine conditions) so that research into the nature and cause of these diseases can proceed.

2. CROP M A N A m

A nw$er of environmental factors (e.9. water supply, soil fertility, tempratwe) influence qrape production and effective vineyard wgement practices aim to optimize both crop quantity and quality d e r particular envimnmental conditions. In addition to standard cultural practices such as irrigation, fertilization, and pruning, the genetic component of crop management is gaining increasing recognition. Wemidous genetic variability exists in

plant response to enviromiental factors, and thus the potential exists to optimize production for particular vineyard sites by the choice of the appropriate cultivar. This is already done to some extent in that it is well-known that specific cultivars perform better in certain enviromts than do others (although the underlying -115 are generally not bown).

The potential to use grape germplasm m e r as a tool in crop management has two mjor limitations at present. First, the specific objectives of such genetic manipulation are unclear. Genetic impmenwit prograrrc; pngress most effectively if specific, identifiable characteristics are dpulated. Then the germplasm being manipulated, mether it be wild species, existing cultivars, seedlings frcnn controlled crosses, or cells in culture, can be efficiently evaluated and promising individuals quickly identified. Most vineyard management problems, however, are known only by their gross effect on the crop. The underlying biolcgical precesses are poorly understocd. ?he role of vineyard management in wine quality is especially ambiguous (see FYduction and Utilization) .

The other major limitation lies in the paucity of information about existing germplasm resources. Such mterial is a potentially rich resource not only for genetic manipulation to prduce imprwed cultivars, but also for imhrmtal investigations into the physiolqical, bicchanical, arid mrpholqical bases of differential response to - environmental factors. However, researchers who might make use of this material are hampered by the almost total absence of information concerning genetic variability for the traits of interest.

Water relations

A n m h r of grape production problems are associated with water, either its availability or quality. Most California vineyards are irrigated, the natural rainfall being either insufficient or unreliable. Cultivars with increased water use efficiency could reduce irrigation needs and minimize the deleterious effects of water stress on vine growth, bud fruitfulness, fruit set, berry growth, sugar acclmrulation, arid leaf abscission. Fruit quality might also be optimized through the genetic manipulation of water relations. The reduced water quality due to salinity in some locations might be werwane by the development of salt-tolerant genotypes. Problems associated with excess water, such as ilocding injury or berry cracking aiter s m w r rain, might also be anenable to genetic solutions if genotypes with increased tolerance to those conditions could be identified. Comparative studies (physiolcgid, biochemical, morpholqical) of grape genotypes differing in their response to water deficits would prcduce new bowledge about the effect of water stress on iwdamental grapevine processes.

Mineml nutrition

Like other crop plants, grapevines acquire essential nutrient elements f m the soil. Plants can differ genetically in their ability to take up and utilize nutrients. Same types are ~mch more effective at acquiring nutrients from the soil and can thus r a i n healthy in deficient soils inadequate for other plants. Others m y utilize nutrients particularly efficiently, gruwing and functioning normally wen thou* they contain a lwer concentration of a nutrient than needed by other plants. While this kind of nutritional genetic variability has not yet been studied much in grapevines, it undoubtedly cccu-s and could be exploited as a mmgement tml to either reduce fertilizer requirements or to produce cultivars suited for infertile soils. Such cultivars (or variants of existing cultivars) could be desirable for such sites as hillside soils with low phosphorus availability or to wercom zinc deficiercy problems in the San Joaquin Valley. Conve?sely, some soils contain excesses of toxic elemnts (e.9. chlorine in salt-affected soils). Cultivars tolerant of these conditions could be prcduced by identifying and exploiting genetic variability in exclusion of or tolerance to these toxic elements. A widespread physiolcgicdl disorder, Wa-, is believed to be related to mineral nutrition. ?he wide differences in cultivar susceptibility known to exist might not only be exploited to produce cultivars or clones less susceptible to this disolder, but could also be used to investigate its basis. Research on all aspeds of grapwine mineral nutrition could be facilitated by the identification and ccanparative study of geno+qps that differ in uptake, utilization, or exclusion of minerals.

T e m ~ e r a t u r e extremes

me of the most serious problems in the grape growing regions of the North Coast as well as the foothills of the Sierra Nevada is spring frost. Gmers expnd large amunts of money and time to protect against frost damage. It is already known that saw cultivars are a better risk for frost prone areas because they avoid frost by breaking bud later than others. It is also known that genetic variability exists in actual tolerance to frost. For example, sme wild American u s species are well-adapted to cold conditions. Such material is of great value for studies of grapevine response to l w temprature (although of limited use in b m because of fruit quality standards) that could lead to improved frost protection practices. A better Werstanding of the precesses involved in both frost tolerance and frost damage might suggest other genetic strategies for improving frost tolerance in vinifera cultivazs.

G r m t h and develonnent

Both the quantity and quality of grape praiuction are closely linked to vine architecture. Vines are pruned to mipulate the

balance between vegetative and crop load and thus maximize fruit quantity with no loss of fruit quality. The structure of the campy is further manipulated by trellising and training to control light exposure to both leaves and fruit. The genetic modification of vine architectme to change the form of the plant canopy auld result in trenen3ou.s savings in labor and mterials as well as possible further iqmvements in crop quality. This concept has been exploited with great success in agronomic crops (for exunple, short stabre rice and wheat cultivars, corn cultivars with more upright leaves) but has not been investigated for grapes.

?he e x w s vegetative vigor characteristic of some cultivars might be reduced genetically. In the shorter term, the influence of rootstock on scion vigor might be M e r exploited by investigating a wide range of potential rootstocks, both existing cultivars and wild species, to identify particular genotypes that impart significant changes in vigor or stature to scions. Dwarfing rcotstccks are cormonly used in other fruit crops (e.9. citrus, apple) but have not been investigated in grape.

Other genetic difications in vine growth or development that would have significant economic impact include increasing the fruitfulness of basal buds in cultivars that must now be cane pruned, decreasing the prcduction of second crop on lateral shoots, decreasing tecdril development, decreasing shoot development from latent buds, and modifying vine architecture to facilitate - mechanical harvesting. Since both OLR and bunch rot damage are more severe in compact clusters, the genetic manipulation of cluster structure to prcduce lcose-clustered clones might reduce these problem. Berry size (as it affects the ratio of skin to berry volume) is also a factor in wine quality and might also be manipulated genetically.

As with other aspects of grapevine function, grape germplasm resources can also contribute to howledge about grapevine growth and development. For example, camparative studies of cultivars differing in the degree of second crop can be used to study the regulation of axillary bud and shoot development. Camparisons of genotypes differing in stature, canopy structure, or vigor may pmvide new information about fundamntal mchanism controlling vine architecture. The factors that govern bud fruitfulness might be identified by investigating genotypes that differ widely in this trait.

successful grape production requires more than mimum crop prcduction for minimum input. Perhaps more than with any other fruit crop, quality factors are essential to the economic value of grapes. These factors can differ, depending upon whether the fruit is for fresh consumption, to be dried for raisins, or to be crushed for wine. Like other features of grapevines, these too are genetically variable and thus can potentially be manipulated.

Table c r a m

More so than w i t h raisin or w i n e grapes, the table grape imiustry is very receptive t o the introduction of new cultivars. m y of the most hprtant California table grape cult ivars today are of relat ively recent origin. E m i t apparance, including both color and shape, is probably the most important quality factor in table grape production. The ab i l i ty t o m i p u l a t e both berry color and shape genetically would be desirable i n the production of new table grape cultivars. For exanple, increased uniformity of color, especially without the need for special cultural practices t o enhance it, would be desirable. Increased berry s ize (especially in seedless cultivars) is also important. Cultivars w i t h better storage characteristics, including strong bersy attachmmt to the cluster and resistance t o rot, are desirable. Season of m t u r i t y is crucial in the table grape m k e t , w i t h cult ivars f i l l i n g distinct color/season niches. New seedless cult ivars very quickly replace older seeded cultivars that m p y the same color/season niche, but do not cmpete w i t h cultivars of other colors o r seasons. Scnne niches are now occupied by new cultivars (e.g. Flame Seedless, an early red seedless, has nearly replaced Cardinal, an early red seeded cultivar) but other niches still contain older, seeded cult ivars (e.g. a l a t e khite seedless cultivar has not yet been developed). New seedless cultivars for these color/season niches would be readily accepted.

Raisin cra~es

For ra is in grapes, the Thompson Seedless raisin is the hlushy norm fo r size, shape, color, flavor, and texture. Although larger- fruited cult ivars are available (e.g. Centennial Seedless) , the kbstq seems t o prefer the medium-sized raisin. Two big concerns for wtlich genetic solutions are possible, however, are losses due to mold caused by rain during the period when the f r u i t is drying on the ground and the economic desirabil i ty of mchine harvesting. An ea r l i e r maturing cult ivar would greatly increase the likelihocd of getting the f rui t dry and off the ground before the not u n m n S e w rain. M d i o n costs could be significantly reduced i f ra i s in grapes could be machine harrested. ?his would be fac i l i t a ted by the develcpent of a cultivar in which the f r u i t could be allowed t o dry on the vine.

Wine cra~es

In w i n e grapes, the most important quality factor is the chemical composition of the f ru i t , since t h i s is the basis fo r the flavor and s t ab i l i t y of the finished wine as well a s fo r the nutri t ion of the yeast during the fermentation p m e s s . Some cult ivars do not have a distinct varietal flavor and thus cannot command the higher prices associated w i t h cultivars w i t h dist inctive flavors. Genetic manipulation t o irqmve varietal character in those cultivars might increase the i r value. Bitterness is a problem

in other cultivars that might be eliminated by the genetic modification of fruit capsition. The warmer regions of California p e e a large proportion of the wine grape crop but this fruit typically prcduces low acid wine of rrsediccre flavor. The genetic potential for reducing this problem has already been demonstrated in the development of several cultivarj adapted to warmer regions. Ruby Cabernet is a notable success in this regard, producing a distinctive wine with acceptable acidity even when g r m in warm regions. Successful fencentations require that the fruit pmvide adequate nutrition for the yeast. Same cultivars typically require that their juice be supplemented with amino acids and vi- to facilitate fermentation because they contain insufficient levels of these cmpur~L~. This deficiency night be overcome by genetic dpulation of fruit composition. It is reasonable to envision that ulthtely m y aspects of wine quality could be manipulated through the genetic modification of fruit composition. However, at the present time, not mch is known about the relationship between fruit conpsition and wine quality. Until specific biochemical cmpnents of frdt that determine varietal character and other aspects of wine quality are clearly identified and the factors that regulate their biosynthesis are elucidated, the potential for the genetic rranipulation of wine quality will be quite limited.

Little research has been done to compare the relative quality of wine p?xduced f m different clones within a cultivar. Perhaps - to fill this void, a great deal of mythology has developed with regard to clones grown in other countries, particularly those )cnm to be virus-infected. Same prcducers are convinced that certain foreign clones produce better wine than those available to them in California. There is also a widespread belief that virus disease inproves wine quality. ??his issue must be clarified to the satisfaction of growers and wine makers through careful, controlled comparisons among clones.

GF.NFTIC RESOUF(CES AND T03LS

The utilization of grape germplasm to address California grape pnxludion problems has a number of prerequisites. Germplasm resources must be available for use and must be sufficiently extensive and well-zhamcterized that the necessary genetic variability can be identified. The effective genetic rranipulation of these resources requires an understandkq of the fundamntal genetic makeup of -s. A range of genetic tezhniques must be available for use, including up-to-date "conventional" breeding methods as well as cellular and molecular techniques, such that the most effective strategy can be used for each specific objective. All of these factors are independent of specific production problems. ?hey constitute the fundamental underpinnings necessary for the application of modern genetics to agricultural problem.

G e m l a m resources

-. While UC Davis has extensive collections of u s germplasm (Table 3 ) (almost entirely due to the efforts of H. P. O m ) , a n W of gaps exist, both in cultivated material and wild species. W i t h respct t o cultivars, we have a paucity of North African m a t e r i a l , of particular interest because of the similarity between the c l h t e of North Africa and that of the San Joaquin Valley. North African cultivars would be e.xpcted t o be particularly w e l l adapted t o high t-ture and &mightt. Some countries (e-g. Afghanistan, Iran) have became less accessible for mllecting; this is particularly unfortunate since these are areas of high genetic diversity for u s , particularly V. vinifera. In t e r m s of wild ws species, the strength of the UC Davis collection is, not surprisingly, in North American accessions. Alnwst a l l the wild germplasm used in breeding has keen from North m i c a , but several other m j o r areas in which wild u s flourish are relatively unexplored. Asia is a center of diversity for ms bt w e have very l i t t l e Asian m a t e r i a l here a t Davis. ?here is also a wealth of material in Central America about which very l i t t le is hm. The tropical American m a t e r i a l has generally been 1umps.d.

Table 3 . Grape germplasm collections a t the University of California, Davis.

Approxirrate Kmker of Accessions

National Department of Clonal Viticulture Germplasm and Enolqy Repository TOTAL

vinifera Cultivars Wine Table

Hybrid Cultivars American French

Kusadine Qlltivars R c o t s t c c k Cultivars Species Intenpecif ic Hybrids Breeding Selections Tetraploids

into a single species, v. caribbea, largely because of ignorance, but this material is quite diverse and likely includes a n m k r of species.

me North American species have contributed a great deal to grape kmvement, particularly rootstock breeding, providing resistance to a number of pests and diseases as well as adaptability to diverse growing conditions. Because the Asian and tropical American species exist in very diverse ecological niches, they would be to possess many traits of interest, notably resistance to biolcgical and enviromtal stresses (e.g. the extreme cold tolerance of the Asian species V. amurensis) .

Some of the material that we lack exists in collections in other parts of the world and might be obtained from researchers at these locations. However, there is substantial risk involved in aspiring germplasm in this rranner. S e v e r a l large collections exist in F-rance, but much of the material is infected with viruses and so is of limited value. While obtaining such material in the form of seeds may partially cixnmwent this problem, such seed is usually the result of cross-pollination with other material in the same planting and is thus genetically undefined. An additional problem associated with obtaining germplasm in this indirect rranner is the increase3 risk of h m error, in both identity and origin, unavoidably incurred in obtaining material from another collection rather than from its original source.

Samolinq. Because grapevines are large plants and grape germplasm is currently maintained as a pemment planting, the number of plants that can be maintained is quite limited. Since only two to four individual plants have generally keen established for any one wild species accession, the question of wfiether the gene pool has been adequately sampled must be considered. Grapevines are genetically highly heterozygous and it is likely that m y more alleles exist in a particular population than are represented by two to four individuals. Even in our relatively extensive collection of North American u s species, there are probably m y alleles of great interest and value in the gene pool that are not represented. Biochemical (e.g. isozyme analysis) and molecular (e.g. restriction fragment length polymcrphisn analysis) methods that can be used to estkte genetic variability do exist, but have not yet been applied to grape. While the issue of sampling strategies has been dealt with by plant geneticists, it has not keen taken up for m s specifically. An asscciatd problem is that all m s collections are as limited as the UC Davis collection, thus descriptions of Vitis species, and the evaluation of their breeding potential, have dlmost always been based up3n only one or two individuals and are probably inaccurate.

It would be highly desirable to maintain a broader sample of u s germplasm than currently exists in our collection. Space and fin- limit the size of field plantings, but other maintenance methods might be developed (see Maintenance, below) .

Characterization. Most of the accessions in the UC Davis collection have not been evaluated for attributes of potential value, although these can be inferred in many cases from the origin

APPENDIX I. Major grape production problems in California.

G =

general problem

F =

problem likely to continue in future

R =

regional problem

W =

problem likely to worsen in future

D =

problem likely to decrease in future

Extent

CWxent

Future

Problem

Status

Control

Control

Rese

arc

h Required

Disciplines Required

PE

TS

AND DISEFSES

Nematodes:

Root-knot

R F

Wqation,

Resistance

Dagger

G

F

Fumigation

Lesion

R W

None

Arthrotxxls:

Fhylloxera G

F

Resistance

Resistance

Investigation of host-

Nmtolcqy

parasite interactions

Plant biochemistry

~dentification of S

OLU

XES

of Plant physiology

resistance

Plant genetics

Elucidation of resistance

Plant molecular biology

mechanism

Breeding program

Gene transfer

Resistance

Resistance

II

I,

Resistance

Entomology

Plant biochemistry

Plant physiology

Plant genetics

Plant molecular biology

W

4

JMYmt

Current

Future

Problem

Status

Control

Control

Res

earc

h Required

Disciplines Required

LeaEhopprsR

F

Chemical

Resistance

II

Biolqical

Investigations of natural

control

enemies

Spider

R F

Chemical

14

mites

Omnivorous R

F

Chemical

II

leafroller

Grapeleaf

R F

Chemical

II

skeletonizer

Diseases:

MerY

G F

Chemical

Resistance

Investigation of host-

Plant pathology

mildew

parasite interactions

Plant biochemistry

Identification of sources of Plant physiology

resistance

Plant genetics

Elucidation of resistance

Plant molecular biology

mechanism

Breeding P

mgr

am

Gene transfer

mtYP

R

F

Chemical,

Resistance

Removal of

diseased parts

Extent

Current

Futwe

mablem

Status

Control

Control

Res

ear&

Required

Disciplines Required

Diseases, continued:

Pierce's

G W

disease

Grapevine

R

F

fanleaf virus

Bunch rot

G

F

Measles

R

F

Leafroll

G D

Chemical

Resistance

None

Resistance

None

Resistance

Chemical

Resistance

Canopy

mnagement

Chemical,

?

but limited

(resistant

clones?)

Clean stock

More rapid

detection

Investigation of effect of

microclimate on disease development

Effect of

cam

py manipulation

on microclimate

Studies of genetic control of

canopy structure

Determine cause of disease

Plant pathology

Developent of molecular

Plant pathology

diagnostic m

eth

od

s

Extent

Current

Future

Problem

Status

Control

Control

Research Required

Disciplines Required

CROP MANAGEMENT

Water relations:

hi

water

G

W

None

use efficiency

Red

uce

d

G

F fruit quantity

and quality due

to water deficits

Mineral stress:

Phosphorus

R

W

deficiency

Zinc

R

F deficiency

Salinity

R

W

None

Drought

Identification of drought

Plant physiology

tolerant

tolerant genotyps

Plant genetics

r00tstccks or Elucidation of tolerance

plant molecular biolcgy

scion clones

mechanisms

Irrigation

medin

g PrOgram

ma~gement Gene transfer

Fertilization

Nutrient

efficient root-

stocks or scion

clones

Fertilization

11

Leaching

Salt-tolerant

m0tstcck.s or

scion clones

Extent

Current

fitwe

m-oblem

Status

Control

Control

Res

earc

h Required

Disciplines Required

Mineral stress, continued:

Ion

R

F None

Resistant mot-

II

toxicity

stocks or scion

clones

Waterkrq R

F None (cause

?

Determine cause of disorder

-1 (cultural prac-

tices, resistant

clones?)

Tenweratwe extremes:

Frost

R

F

wind machines, Frost-tolerant Identification of drought

Sprinkle-,

clones

tolerant genotypes

wge po

ts,

Elucidation of tolerance

oouble pruning

mxhanisrrs

Breeding P

rogr

am

Gene transfer

Bacteria?

Field trials with non-

nucleating bacteria

Gra

hJth

and development:

com

pact

G

F

and thinning

Iess c

vn

pct

Identify desirable genotypes

clusters

or mne

clones

Elucidate underlying

developrental mechanism

Clonal selection

Gene transfer

Plant physiology

Plant physiology

Plant genetics

Plant molecular biology

Plant pathology

Plant physiolcgy

Plant physiology

Plant genetics

Plant molecular biology

Ex

ten

t C

urr

ent

Fu

ture

P

robl

em

Sta

tus

Co

ntr

ol

Co

ntr

ol

Res

earc

h R

equir

ed

Dis

cip

lin

es R

equir

ed

Gro

wth

and d

evel

opm

ent,

co

nti

nu

ed:

LCNJ b

ud

?

F

Can

e p

run

ing

M

ore

fru

itfu

l 11

fru

itfu

lne

ss

clo

nes

Ex

cess

ive

G

F

Han

d tr

imby,

W-v

igo

r II

vig

or

chem

ical

1ootstocks,

or

none

L

aw-v

igor

cl

on

es

PRODUCTION AND U

PIL

.IZA

TIO

N

Tab

le c

frap

es:

Poo

r fr

uit

G

F

C

hem

ical

In

P=

JV

d

Ide

nti

fy d

esi

rab

le g

eno

typ

es

Pla

nt

ph

ys

iolq

c

olo

r o

r no

ne

clo

nes

E

luci

dat

e u

nd

erly

ing

P

lan

t g

en

eti

cs

New

dt

iv

ar

s

de

ve

lop

en

tal

mec

hani

sms

pla

nt

mo

lecu

lar

bi

ol

q

Clo

nal

se

lec

tio

n

Breeding p

rcgr

am

Ge

ne

tra

nsf

er

Sm

all

G

F

I,

berr

ies

Rai

sin

qra

pes

:

Rai

n d

amag

e G

F

N

one

Earl

ier

clo

nes

11

or

cv

ltiv

ars

Extent

Current

Future

m-oblem

Status

Control

Control

Research Required

Disciplines Required

Raisin grapes, continued:

Machine

G

F

None

Cultivars or

II

harvestability

clones better

suited to

mechanization

Wine grapes:

Se

co

nd

crop G

F

Hand removal

Clones with

II

unfmitN laterals

ILN acid

G

F

None

Clones with

Identify desirable genotypes Plant biochemistry

higher

Elucidate underlying

Plant genetics

organic acid

biochemical mechanism

Plant molecular biology

content or

Clonal selection

reduced res- Gene transfer

piratoq loss

of acid

ILN

G

F

Cultural

Clones with

II

varietal

practices

enhance

d varietal

character

character

Bitterness G

F

None

Clones with

11

reduced bitterness

kw

amino

R

F

Addition to

Clones with higher

11

acid and

juice prior to amino acid and

vitamin content

ferntation

vitamin content

APPENDIX 11: Current grape rsearchers in California, including University of California faculty, UC Cooperative Extension specialists, and USDA scientists, in full-time equivalents (ETE). (Sunrmarized in Table 4.)

Abbreviations:

AFS California State Agricultural Eqeriment Station CES Univexsity of California Cooperative Extension Service USDA united states Department of Agriculture

NAME A F F I W O N AND E C A T I O N FIE ON

DISCIPLINE GRAPE

Genetics:

Dandekar AES, Pomolcgy, Davis Molec. Biolcgy .10 Mer€dith AES, Viticulture & Enolcgy, Davis Genetics 1.00 m i t t AES, Pomology, Davis Genetics .30 m USDA, %no Genetics .40

Crop Management:

Adams AES, Viticulture & Enolqy, Davis Christiansen CES, Kearney Falcon AES, Entmlogy, Berkeley Grimes AES, Iand Air Water ReMurces, Davis Jerwn m, -eY Kliewer AES, Viticulture & holcgy, Davis Labavitch AES, Rxmlqy, Davis Matthews AES, Viticulture & Fnology, Davis Morrison AES, Viticulture & Enolcgy, Davis P r i M CES, StccMon W i l l , D. AES, IH4 Implementation, Davis Williams, L. AES, Viticulture & Eholcgy,Kearney Wolpert CES, Viticulture & Enolcgy, Davis

Biochemistry 1.00 Crop Management .45 Meteorolcgy .05 Water Managemt .30 Crop Management .50 Fhysiolcgy 1.00 Fhysiolcgy .10 Fhysiolcgy 1.00 Fhysiolcgy - 1.00 Water Management .10 Computer Mcdeling .lo Fhysiolcgy 1.00 Fhysiolcgy .50

TOTAL CROP MANAGETENT 7.10

-

FTE ON MIME AFFILLATION AND IDCATION DISCIPILNE QAPE

DeVay mds Falcon Gonzales Gmett Gubler Kirkpatrick Marois

Raski s-cik stern '4'-to Welter Wil&m Williams, D. Wilson (pending) (pending)

AES, Plant Pathology, Davis AES, Plant Pathology, Riverside AES, htmlogy, Berkeley AES, htomology, Riverside AES, htomology, Davis CES, Plant Pathology, Davis AES, Plant Pathology, Davis AFS, Plant Patholcgy, Davis AES & m, m e y AES, Nmtology, Davis AES, Plant Pathology, Riverside AES, htmlogy, Riverside USDA, Plant Pathology, Davis AES, Esltmlcgy, Berkeley CES, Land Air Water Reso-, Davis AES, IFM Implemntation, Davis AES, Eritomology, Davis USDA, Plant Pathology, Davis AES, Plant Pathology, Davis

Pathology .20 Pathology .05 Meteorology .05 htomology .25 htomology .50 Pathology .10 Pathology .15 (st.) Pathology .80 Nemat0logy .20 Ne~MtOlcgy .50 Pathology .20 Eritmlogy 1.00 Pathology .30 (est.) htom3lcgy .35 Soil Science .30 cmputer Weling .lo htomology .50 - Pathology .50 (est. ) Pathology .50 (est.)

TOTAL PEST 6.55

-ton AES, Viticulture & hology, Davis Biochemistry .10 christiansen CES, K e a r n e y Raisin Prep. .05 Harvey USDA, %no Postharvest .10 Mitchell AES & CES, Pomolcgy, Davis Postharvest .10 mgfi AES, Viticulture & hology, Davis Chemistry .25 Singleton AES, Viticulture & holcgy, Davis Chemistry .40 Studff AES, Aqric. Engineering, Davis Mechanization .30

TOTAL OZ1W 1.30

CrRAND TOTAL 16.75

t,mer~t includes grape composition and natural products chemistry, table grape storage, raisin quality, and mechanization.