G. McGranahan, R. Snyder, D. Ramos, H. Forde, H. Phillips, and C. Leslie

Transcription

1 EVALUATION AND DEVELOPMENT OF VALNUT SEEDLINGS, SELECTIONS, CULTIVARS, AND INTRODUCTIONS G. McGranahan, R. Snyder, D. Ramos, H. Forde, H. Phillips, and C. Leslie ABSTRACT This report contains tables and descriptions of some of the material under evaluation at UC Davis. It includes phenology and crack out data for established cultivars, selections and French introductions. It also includes brief descriptions of the selections that are available under test agreement. Crosses made in the course of the UC-USDA breeding program ( ) are presented in tabular form. This year 23 different crosses were made resulting in almost 1200 nuts. Seedlings (n-6l2) from 1990 crosses were germinated and are ready for transplanting to a seedling evaluation block. Seedlings from crosses made in 1986 and 1987 are in the initial years of evaluation with some showing precocity. UC67-ll was named Tulare and was submitted for patenting. It is primarily recommended as a replacement for Chico in close plantings. OBJECTIVE The general objective of this project is to evaluate and introduce new cultivars and rootstocks that will serve the needs of the California walnut industry. The specific objectives are: a) to continue evaluations of seedlings, domestic and foreign introductions, selections and cultivars in our collection; b) to identify pollenizers for Chandler, Howard, and Hartley by evaluating seedlings from recent controlled crosses; c) to introduce germplasm which will broaden the genetic base available for breeding and d) to make crosses for the UC-USDA breeding program in order to provide improved lateleafing cultivars for the industry. The rootstock development report, and the high density management system report are submitted separately. PROCEDURE Data is collected annually on the following traits: dates of leafing and harvest, dates of first, peak and last pistillate and staminate blooms; precocity; catkin abundance; percent lateral fruitfulness; number of pistillate flowers per inflorescence; dichogamy; blight incidence; tree vigor; growth habit; estimated yield; shell shape, texture, strength, and seal; nut and kernel weight and resulting percent kernel; kernel fill and plumpness; ease of kernel removal; kernel color; type and frequency of kernel shrivel; and frequency of kernel blanks. Diamond Walnut Growers makes a substantial contribution by providing this program with a commercial crack out evaluation of selected materials. Each year a panel reviews the data, examines the kernels and recommends action (save for further evaluation, select, discard, or "bank" in a germplasm collection). Materials that are considered "advanced selections" are made available to cooperating growers under test agreement. The new UC-USDA breeding program is in its second of three years. The goal of

2 the program is to incorporate foreign germplasm into the breeding program and to produce populations of seedlings for cultivar selection. Standard techniques are used to collect pollen, isolate female flowers in pollination bags and inject pollen of the selected male parents. Seed are then collected, dried, stratified and planted in a nursery. After one growing season they are undercut and transplanted to a seedling evaluation block. After three years they are incorporated into the standard evaluation program. RESULTS AND CONCLUSIONS A list of all materials in the program is available in the 1992 proposal and from the authors. The list which contains additional information is entitled "five year field plans". Cultivars: Leafing dates spanned a long period this year because Payne and other early cultivars leafed out earlier than usual and Franquette and other late cultivars leafed out later than usual (Table 1). Yields were generally good, but blight was somewhat worse than usual on early cultivars. Harvest season was later than usual for the late cultivars (Table 2). Color was generally good, but shrivel was a problem in some cultivars, especially (Tulare) and Chandler.. Selections: Selections are described in Tables 1, 2 and 3. Tulare, (67-11), was described and submitted for patenting this year. Tulare is recommended primarily as an improvement over Chico for close plantings. During crack out last year the decision was made to discard Other discards include 67-13, , 72-13, and Seedlings: Under evaluation are 72 seedlings from crosses made in 1986 and 102 seedlings from crosses made in At least one parent in almost all crosses is protogynous. Of the 1986 crosses 26 flowered but more than half of these dropped their flowers. Six are both late leafing and laterally fruitful; five of these are from the cross XXX Mayette X Chandler. Of the 1987 crosses 46 flowered and 35 of these were laterally fruitful. Flower drop was also a problem in. this set. It is unknown whether the drop was caused by lack of pollen, pistillate flower abscission or other cause. Introductions: Introductions include seed and scionwood from the following countries: China, Korea, India, Pakistan, Yugoslavia, Poland, Bulgaria, Hungary, Romania, France, Italy, Spain, Canada and US. Many of the Eastern European kernels are dark, while the French walnuts generally have light kernels. Selections from E. Germain's breeding program are all late leafing and laterally fruitful (Tables 4 and 5). The two with Franquette X Lara parentage appear most promising. The material from China which was introduced in 1985 is generally laterally fruitful, and very precocious, but early leafing and with somewhat dark kernels. Chinese introductions from the 1990 McGranahan/Leslie/Barnett trip have been germinated and are growing in pots in the lath house. Wood will be collected for grafting in These have not been put directly in the field because the Walnut Crop Advisory Committee recommends that all introduced English walnut seedlings be grafted on black or Paradox rootstock before being grown in the field. UC-USDA Breeding ProEram

3 Seed collected from controlled crosses in 1990 were stratified and planted in the nursery. Germination of the 20 families ranged from 16% (Cisco X 67-13) to 100% (Cascade X Sunland) resulting in a total of 627 seed ready for undercutting and transplanting to a seedling evaluation block. The land for this block has been prepared and is set up for microsprinkler irrigation and 10 by 20 ft spacing. Additional controlled crosses were made in 1991 to further complete the crossing design. These included 23 crosses resulting in 1192 nuts, which have been dried and are ready for stratification. The crossing design, numbers of seed and resulting seedlings are shown in Tables 7 and 8. Field Trial Summaries Rootstock, cultivar and selection trials have been established by UC Cooperative Extension Farm Advisors in 9 counties (Tables 9 and 10). Some trials are small, designed to evaluate a few specific clones or seed sources; others involve extensive collections of species or selections/cultivars grown under different training systems. This year data collected at the plots of Sibbett, Reil, and Hasey were used to describe (Tulare) in HortScience

4 TABLE1. CULTIVARANDSELECTIONEVALUATIONS ATU.C. DAVIS(SPRING1991) X LeaLfr'll b Pollen Sheddina Pistillate Bloom Frui tful Cultivars/Selectlons (Cross) Date DAP 5yr 1st Peak Last Atuldanc:e" 1st Peak Last Laterals Yielcf Blight. Reference PAYNE / / / HARTLEY /11 4/24 6 4/14 4/20 4/ SCHFRANQUETTE 4/ / /19 Established SERR(PAYNEX PI ) 3/ /31 4/ / ASHLEY / / / CHICO(SHARKEYX MARCHETTI) 3/ / /23 3/30 4/ SUNLAND(L(M)OC X PI ) 3/ /31 4/ / VINA (PAYNEX SCHFRANQUETTE) 3/ / / /13 4/ TEHAMA(PAYNEX WATERLOO) / /14 4/ AMIGO(SHARKEYX MARCHETTI) /12 4/ /10 4/ c:.. PEDRO(PAYNEX C. MAYETTE) 3/ /11 4/21 6 4/13 4/ HOWARD(PEDROK ) / /12 4/19 4/ CHANDLER(PEDROK ) / /14 4/ CISCO (PEDROK MEYlAN) 4/ /12 4/ / / Select ions TULARE, (TEHAMAK SERR) 3/ / /10 4/14 4/ (TEHAMAK SERR) 3/ / /11 4/ ( X 53-39) **** discontinued **** (53-39 X CHICO) /16 3 4/11 4/12 4/ (CHANDLERX 61-25) /10 4/12 4/19 5 4/17 4/ (HRD X 64-57) / (HOWARDX 64-57) /18 4/ ( X CHANDLER) 4/ / /26 5 4/ / "DAP" denotes "days after PayneN. b Superscripts indicate numberof years for average, If 5 years of data not avaitabte. C Catkin abundance: 0 - no catkins, 9 - extremety dense catkin production. d Yietd estimete: 0 - no walnuts, 9 - extreaely high yield. Blight score: 0 - no sign of infection, 9 - extremety severe Infestation.

5 TABLE 2. CULTIVAR AND SELECTION HARVESTEVALUATIONSAT U.C. DAVIS (FALL 1991) Harvest Shl'l! Avg. Weight % Kerr1 Kernel- Kernel Color (%), Kernel Shrivel (%), Shell C SheIt d Thick" In-Shell Kernel 5 yr FI It Light a 5 y Cultivars/Selections (Cross) Date DAP avg Seal Strength (RIll) (IJIIIS) (IJIIIS) 1991 avg Grade Light Anber Anber TIp <50 50 Blank Reference PAYNE 9/ HARTlEY 10/ SCHFRANatJE HE 10/ Establ ished SERR(PAYNEX PI ) 9/ ASHLEY 9/ CHICO(SHARKEYX MARCHETTI) 9/ SUNLAND(UJIPOCX PI ) 10/ VINA (PAYNEX SCHFRANatJETTE) 9/ TEHAMA(PAYNEX WATERLOO) 9/ AMIGO(SHARKEYX MARCHETTI) 9/ PEDRO(PAYNEX C. MAYETTE) 10/ HOWARD (PEDROX ) 9/ , CHANDLER(PEDROX ) 10/11, , CISCO(PEDROX NEYLAN) 10/ , Selections TULARE, (TEHAMAX SERR)10/ (TEHAMAX SERR) 9/ ( X 53-39) **** dlscontl **** (53-39 X CHICO) (CHANDLERX 61-25) 10/ " " (HOWARDX 64-57) 9/ (HOWARDX 64-57) 9/ " ( X CHANDLER) u 28". - u_ a b "ClAP.denotes "days after Payne". c SUpencrtpts Indlcete IUlber of yeers for everage, If 5 yeers of data not available. d Shan Seel: percent with open seel Inter slight pressure. Shall Strength: 1 - strong, 4 - very week.. f Karne' Fill: 3 - well, 7 - poor. Kernel Color end Shrivel taken on 10 rendolllly selected nuts, other trelts on ten sound ruts.

6 TABLE 3. DESCRIPTIONOF UC SELECTIONS Patent nrocess underway 'Tulare'. This selection is in the process of being patented and released. A complete description has been circulated to Farm Advisors and will be published in HortScience in early This is a laterally fruitful selection that leafs out in mid-season and sheds pollen during most of its female bloom period. It has an upright growth habit and has produced excellent yields in high density plantings. It is primarily targeted to replace Chico in close plantings. Tulare has been released under test agreement to Stuke Nursery, J. Repanich, Driver Nursery, J. Conant, J. Fukumoto, W. Erdman, E. Germain-INRA, D. Schuering, D. Bonilla, J. Hall, W. Berg, R. Wooley, A. Suchan, and N. Zanella Saved for additional evaluation This selection leafs out 3 to 6 days before Hartley. It is protogynous and a potential pollenizer for mid-season cultivars. It produced catkins in the second season ftom grafting which suggests that it may be precocious. Because it was repropagated recently, nuts were not available for evaluation this year. In past years it has been harvested 3 to 5 days before Hartley and yield has been above average. Nut and kernel characteristics need further evaluation " This is a laterally fruitful selection with a phenology similar to Hartley, although in some years it has been ready for harvest earlier. Further evaluation of nut and kernel quality is needed has been released under test agreement to D. Schuering, A. Suchan, N. Zanella & These two siblings are very similar to each other. Their unusual attribute is a short growing season. They leaf out and bloom with Hartley but harvest with Payne. The nuts are usually similar to Chandler, but in 1991 there were some darker kernels. These selections have,been evaluated while growing on their own roots in a crowded seedling selection block and their performance under normal growing conditions is unknown. Their poor rating in color this year will have to be investigated. They were repropagated in UC orchards in has been released under test agreement to D. Schuering has been released to D. Schuering, D. Bonilla, A. Suchan, and N. Zanella This selection has been of interest because it is similar to Cisco but harvests with Chandler. Color was a problem in 1990 and since the mature trees were removed this year, nut and kernel quality could not be evaluated in has been released under test agreement to D. Schuering, J. Bricker, A. Suchan, and N. Zanella. Discard_or bank This was originally selected for superior yield and nut quality but recently was found to be highly susceptible to pistillate flower" abscission. Because it will not be released it is no longer considered a selection. It has been repropagated in the Pomology Germplasm 6

7 Collection because of superior yield and quality traits has been released under test agreement to Driver Nursery, J. Fukumoto, W. Deardorff, Burchell Nursery, B. Waite, D. Schuering, and N. Zanella Originally selected for high yield and mid-season phenology, this was discarded in 1990 due to small nut size and variable quality. It has been repropagated in the Pomology Germplasm Collection because it shows some tendency to bear nuts in the shade. This attribute has not been confirmed has been released under test agreement to Stuke Nursery, Driver Nursery, and J. Fukumoto Originally selected as a potential pollenizer for mid-season cultivars, this individual was recently discarded because of inadequate lateral fruitfulness. It is no longer available has been released under test agreement to D. Schuering Originally selected as a potential pollenizer for mid-season cultivars, this was discarded in 1990 due to potential pistillate flower abscission. This flaw was recently confirmed by Walt Deardorff and Kathy Kelley. It has not been repropagated and is no longer available has been released under test agreement to D. Schuering, J. Bricker and N. Zanella. Other discarded selections under test agreement include , and (Driver Nursery), and (D. Schuering)

8 TABLE4. FRENCHINTRODUCTION EVALUATIONS AT U.C. DAVIS(SPRING1991) X Leafing Pistillate Bloom Frui tful Pollen Shedding b Cultivars/Selections (Cross) Date DApa 1st Peak Last Abln:Iance 1st Peak Last Laterals Yieldc Reference Blightd PAYNE 3/ / 2 4/13 7 4/ / HARTlEY 4/ / 3 4/ / / SCHFRANQUETTE 4/ /18 4/ /19 French Introductions Verdot, RA118 5/ / 6 5/ 9 5/16 4 5/ 9 5/17 5/ Soleze, RA /12 4/18 5/3 4 4/18 4/24 5/ Ronde de Montignac 5/ /17 5/20 5/28 3 5/13 5/ Meylannaise, RA / /25 5/ 4 5/14 4 4/ / CHASE09, RA / /12 4/18 4/ J. purpurea, RA1088 3/ / /12 4/ CR 1-1 (J. cordiformis X J. regia) 4/ 1 25 Lara, RA480 4/ /12 4/ /14 4/20 5/ to J. nigra, NG / / / 6 5/ J. maior, NG209 4/ / 8 5/ / / J., HD6-15 3/ / 6 5/12 5/17 7 4/ French Selections H (FRANOUETTE X PAYNE) 3/ /11 4/ / / H (FRANOUETTEX PAYNE) 4/ /13 4/ / / H (FRANOUETTE X LARA) 4/ / 8 4 5/ 5 5/12 5/ H (franouette X LARA) /28 5/ 8 5/17 75.' 4 0 H (franouette X ASHLEY) 4/ /14 4/ H 93-9 (FRANOUETTEX PEDRO) / / 8 5/ H97-13 (SOLEZEX LARA) 4/ / 7 4/10 4/13 2 4/19 4/26 4/ ''DAP"denotes "days after Payne". b Catkin abln:lance: 0 - no catkins, 9 - extremely dense catkins, 9 - extremely dense catkin production. :Yield estimate: 0 - no walnuts, 9 - extremely high yield. Blight score: 0 - no sign of infection, 9 - extremely severe infection.

9 TABLE5. FRENCHINTRODUCTIONHARVESTEVALUATIONSAT U.C. DAVIS (FALL 1991) Hervest Shell Avg. "eight Kerneld Kernel Color (X). Kernel Shrivel (X). Shell b SheII C Thickness In-Shell Kernel Fi II light Cultlvers/Selections (Cross) Dete DApa Seel Strength (m) (gills) (gills) XKERNEl Grade Light A/rber Anber Tip <50 t50 8lank Reference PAYNE 9/ HARTlEY 10/ SCHFRANQUETTE 101Z French Introductions VerOOt, RA / Soleze, RA / Ronde de Montignec 101Z Meylennalse, RA Z CHASED9, RA \0 J. purpurea, RA u_ u_ u_ CR 1-1 (J. cordiformis X J. regie) Lera, RA 1, , J. nigra, NG23 J. maior, NG209 J. hindsii, HD 6-15 French Selections H (FRANQUETTEX PAYNE) 101Z , , H (FRANQUETTEX PAYNE) 10/ H (FRANQUETTEX LARA) 101Z H (FRANQUETTEX LARA) 101Z , H (FRANQUETTEX ASHLEY) 101Z H 93-9 (FRANQUETTE X PEDRO) 101Z H (SOLElE X LARA) b "DAP"denotes "days after Payne". Shell Seet: percent with open seet under stight pressure. C d Shett Strength: 1 - strong, 4 - very week. Kernet Fltt: 3 - wett, 1 - poor. e Kernet Color end Shrivel taken on 10 rendollllyselected nuts, other traits on ten scxn:l nuts.

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11 TABLE 7. Crossing diallel for germplasm incorporation (no. seedlings/ no. seed) Male parent Female 85-8 Sinens Isr.i J purpurea Manreglan Chaae09 parent year Chandler / Howard /149 35/ / Vine /116 61/ /120 Tulare / /85 62/111 1' TABLE 8. Crossing group for late leafing, high quality and lateral fruitfulness (no. seedlings/no. seed) Male parent Female Sunland Chico Chandler Howard r;ranquette parent year C. Mayette /43 41/ Franquette /25 14/31 14/ / Cisco / Cascade / / Soleze /

12 TABLE 9. CULTIVARAND SELECTION FIELD STUDIES Walnut Cu1tivar and Selection Performance in High Densitv Configuration Principal Investigator: G. Steven Sibbett Cooperator: L. Bennett Location: Visa1ia, California Established: 1983 Design: 15 cultivars or selections (Ashley, Amigo, Chandler, Chico, Hartley, Howard, Payne, Pedro, Serr, Sunland, Tehama, Vina, UC 76-11, UC 67-13, and UC ) were planted in 9 tree plots (20' x 10' spacing, 3 trees per row by 3 rows wide) replicated 3 times. Evaluations: Bloom characteristics, yield, nut quality and vegetative growth characteristics. Walnut Research Reports, "Tulare" Persian Walnut. HortScience (in press). Walnut Cultivar Performance in High Density Configuration Principal Investigator: Wilbur O. Reil Cooperator: C. McNamara Location: Winters, California Established: 1984 and 1985 Design: Evaluations: 5 cultivars (Chico, Vina, Chandler, Howard, and Amigo) were planted at two spacings (18' x 9'; and 22' x 11'). Rows oriented eastwest. Yield, nut quality, and vegetative growth characteristics. Walnut Research Reports Walnut Cultivar and Selection Performance in High Density Configuration Principal Investigator: Wilbur O. Reil Cooperator: J. Fukum~to Location: Winters, California Established: 1985 Design: 14 cultivars (Amigo, Ashley, Chandler, Chico, Howard, Payne, Pedro, Sunland, Tehama, Vina, UC 67-11, UC 67-13, UC , and Cisco [UC 178, established 1987]) were planted at 22' x 11' spacing. Ten tree plots are replicated 4 times. Evaluations: Bloom characteristics, yield,. nut quality, and vegetative growth characteristics. Walnut Research Reports, "Tulare" Persian Walnut. HortScience (in press). Walnut Cultivar and Selection Performance Principal Investigator: Lonnie Hendricks Cooperator: B. Crane Location: Merced, California Established: 1978 Design: 10 cultivars (Chandler, Chico, Howard, Serr, Sunland, Tehama, UC , UC , UC , and UC 64-57) were planted at 28' x 28'

13 spacing. Evaluations: Bloom characteristics, yield, and nut quality. Walnut Research Reports Walnut Cultivar and Selection Performance Principal Investigator: Lonnie Hendricks Cooperator: B. Crane Location: Merced, California Established: 1987 Design: 10 cultivars and selections (Chandler, Cisco [UC ], UC 67-11, UC 67-13, UC , UC 76-39, UC 76-80, UC , UC 77-12, UC 78-57) were at standard spacing UC and added. Evaluations: Leafing date, bloom characteristics, yield and nut quality. Walnut Research Reports Selection Performance Principal Investigator: Lonnie C. Hendricks Cooperator: G. Schmidt Location: Merced, California Established: 1985 Design: 6 selections (UC 67-11, UC 67-13, UC , UC , UC , and UC 75-74). Evaluations: Yield, nut quality, and vegetative growth characteristics. Cultivar and Selection Performance in Coastal Principal Investigator: William H. Coates Cooperator: Multiple Location: Design: Valley Region 7 cultivars and selections (Payne, Serr, Howard, Chandler, Pedro, Hartley, and UC 64-57) established in standard plantings. Evaluations: Leafing date, bloom characteristics, blight susceptibility, yield, and nut quality. Walnut Cultivar and Selection Performance Principal Investigator: Kathleen M. Kelley Cooperator: W. Deardorff Location: Hickman, California Established: 1984 Design: 15 cultivars and selections (Amigo, Chandler, Howard, Marchetti, Pedro, Cisco [UC ], UC 67-11, DC 67-13, UC , UC 76-80, UC 76-98, UC , DC 77-12, UC 78-10, and DC ) were established in a standard planting. Evaluations: Leafing date, bloom characteristics, yield, nut quality, and vegetative growth characteristics. Cultivar and Selection Performance Principal Investigator: William H: Olson Cooperator: William Stuke Location: Gridley, California Established:

14 Design: 4 cultivars and selections (Cisco [UC ], UC 67-11, UC 67-13, UC ) were established in limited numbers in a standard planting. Cultivar Performance Principal Investigator: William H. Olson Cooperator: C.S.U. Chico Location: Chico, California Established: 1987 Design: Cultivar Cisco (UC ) was established as a pollenizer in a standard planting. Cultivar Performance Principal Investigator: Daniel M. Irvin Cooperator: C. Dunlap Location: West Point, California Established: 1985 Design: Cultivar Cisco (UC ) was established in limited numbers as a pllenizer in a standard planting. Cultivar Performance Principal Investigator: Joseph A. Grant Cooperator: J. Gotelli Location: Stockton, California Established: 1987 Design: Cultivar Cisco (UC ) was established on 10 trees as a pollenizer in a standard planting. Selection Performance Principal Investigator: Janine K. Hasey Cooperator: J. Conant Location: East Nicolaus, California Established: 1984 Design: Selection UC was established on 50 trees in a standard planting. "Tulare" Persian Walnut. HortScience (in press). Cultivar Performance Principal Investigator: G. Steven Sibbett Cooperator: R. Waite 14

15 Location: Bakersfield, California Established: 1988 Design: Selection UC was established on approximately 200 trees in a standard planting. Cultivar Performance Principal Investigator: Joseph W. Osgood Cooperator: R. Darrow Location: Vina, California Established: 1988 Design: Cultivar Cisco (UC ) was established on a limited number of trees as a pollenizer in a standard planting. estimates, and relative tree vigor. Publications; Selection Performance Principal Investigator: Joseph W. Osgood Cooperator: J. Repanich Location: Corning, California Established: 1984 Design: Selection UC was established on a limited number of trees in a standard planting. estimate', and relative tree vigor. Cu1tivar Performance Principal Investigator: Joseph W. Osgood Cooperator: W. Sartori Location: Cottonwood, California Established: 1984 Design: Cu1tivar Cisco (UC ) was grafted as a pol1enizer in a standard planting. Cultivar Performance in High Density ConfiEuration Principal Investigator: G. Steven Sibbett Cooperator: L. Bennett Location: Visalia, California Established: 1987 Design: Cultivar Cisco (UC ) was established on 2 trees as a pollenizer in a 20/ x 10/ hedgerow planting. Cultivar and Selection Performance in Hi~h Density Configuration Principal Investigator: Wilbur O. Reil 15

16 Cooperator: David Scheuring Location: Guinda, Yolo County, California Established: 1989 Design: 10 cultivars (Chandler, Cisco, UC 67-11, UC 67-13, UC 72-13, UC 76-80, UC 77-10, UC 77-12, UC 78-10, and UC ) were planted 11' x 22'. Four tree plots are replicated three times on two different rootstocks (Northern California Black Walnut and Paradox). Observation plantings of four other varieties (UC 76-98, Lara, Ronde Montignac, and Meylannaise) are also present. Eight acres of UC are planted by trial. UC added in Evaluations: Bloom characteristics, yield, nut quality, and vegetative growth characteristics. Cultivar Performance Principal Investigator: Joseph A. Gr~nt Cooperator: J. Gotelli Location: Stockton, California Established: 1987 Design: Cultivar Cisco (UC ) was established on 10 tress as a pollenizer in a standard planting. Selection Evaluation Principal Investigator: Kathleen M. Kelley Cooperator: R. Driver Location: Modesto, California Established: 1984 Design: 6 selections (UC , UC , UC 67-11, UC 67-13, UC , and UC 75-74) were established in limited numbers in a standard planting. esti~ate, and relative tree vigor. Cultivar and Selection Performance Principal Investigator: Kathleen M. Kelley Cooperator: Burchell Nursery Location: Stanislaus County, California Established: 1988 Design: Cultivar Cisco (UC ) and selection UC were established in limited numbers in a standard planting. Cultivar and Selection Performance Principal Investigator: William H. Coates Cooperator: N. Zanella Location: Hollister, California Established: 1990 Design: 1 cultivar and 6 selections (Cisco [UC ], UC 67-11, UC 67-13, 16

17 UC 76-80, UV 77-12, UC 78-10, and UC ) were established in a standard planting. Evaluations: Leafing date, bloom characteristics, yield, nut quality, and vegetative growth characteristics. Walnut Selection Performance Principal Investigator: Joseph A. Grant Cooperator: B. Vink Location: Tracy, California Established: 1990 Design: UC established in limited numbers for field evaluation

18 TABLE 10. ROOTSTOCKFIELD STUDIES Walnut Rootstock Performance Principal Investigator: Lonnie C. Hendricks Cooperator: W. Linville Location: Gustine, California Established: 1986 Design: 5 rootstocks (J. regia Manregian seedlings, J. regia India seedlings, J. regia Amigo seedlings, J. hindsii Rawlins and Rawlins [Calvert], Paradox) were planted in 5 tree plots replicated 3 times. Vina was budded onto the rootstocksin 1987 with Vina scions applied to.failures in Evaluations: Survival, initial rootstock vigor, comparative vigor of Vina, yield, nut quality, nematode tolerance, and salinity tolerance. Walnut Species Rootstock Performance Principal Investigator: Janine K. Hasey Cooperator: J. Conant Location: Rio Oso, California Established: 1987 Design: 7 rootstocks (J. cali ornica seedlings, J. major seedlings, J. microcarpa seedlings, J. hindsii seedlings, Paradox seedlings, clonal Paradox and J. ailanthi olia seedlings) grafted to Chandler were planted at a 25' x 25' spacing (except J. ailanthi olia established at'a 12.5' x 25' spacing) in a randomized complete block design with 20 replicates. Evaluations: Survival, relative tree vigor, yield, and nut quality. Walnut Species Rootstock Performance/Tolerance to A. mellea Principal Investigator: Wilbur O. Reil Cooperator: C. McNama~a Established: 1986 Design: 11 rootstocks (Rawlins [Calvert] paradox [various sources], Royal, J. hindsii Rawlins, J. regia Manregian, J. regia Amigo," J. cali ornica [So. Calif. Black], J. microcarpa [Texas Black], J. nigra [Eastern Black], J. ailanthi olia [Japanese Black], and J. major [Arizona Black] were planted in 4 tree plots replicated 4 times. Evaluations: Survival (toleranceto A. mellea), relative tree vigor. Walnut High Densitv. Soil Modification and Rootstock Performance Principal Investigators: William H. Krueger and John P. Edstrom Cooperator: Nickel's Estate Soils Laboratory Location: Colusa County, California Established: 1986 Design: 2 rootstocks (J. hindsii Rawlins and Rawlins paradox) grafted to either Chandler or Howard were planted in 5 tree plots replicated 6 times in a completely randomized design. Additionally, one half of 18

19 the plots were "slip plowed." Evaluations: Relative tree vigor, yield, and nut quality. Walnut Rootstock Performance Principal Investigators: Joseph W. Osgood and Father Joseph Cooperator: Trappist Monastery Location: Vina, California Established: 1986 Design: 4 rootstocks (J. regia Eureka, J. regia Manregian, clonal paradox, and rooted Chandler) were established. Evaluations: Survival, relative rootstock vigor, yield, and nut quality. English Walnut Rootstock Performance Principal Investigator: Joseph A. Grant Cooperator: James Ferrari Location: Linden, California Established: 1989 Design: 5 rootstocks (J. regia Manregian seedlings, J. regia Eureka seedlings, J. regia Spain seedlings, J. regia Ronde de Montignac seedlings, and J. regia Carne seedlings) established in a randomized complete block design. Evaluations: Survival, relative rootstock vigor, yield, and nut quality. Design: 5 rootstocks (J. regia Manregian seedlings, J. regia Eureka seedlings, J. regia Spain seedlings, J. regia Ronde de Montignac seedlings, and'j. regia Carne seedlings) grafted wi~h Chandler were planted in 5 tree plots replicated 3 times. Evaluation: Relative tree vigor, yield, and nut quality. Walnut Rootstock Performance Principal Investigator: Kathleen M. Kelley Cooperators: James De~artini (grower) and David Bonilla (nurseryman) Location: Modesto.,California Established: 1989 Design: 7 rootstocks (J. regia Manregian seedlings, J. regia Eureka seedlings, J. regia Spain seedlings, J. regia Ronde de Montignac seedlings, J. regia Carne seedlings, J. regia Serr seedlings, and Paradox seedlings) grafted with Chandler were planted in 5 tree plots replicated 3 times. Evaluations: Relative tree vigor, yield, and nut quality