Project Title:Plant Genetic Resources Conservation and Utilization

Project Number:S-009

Project Title:Plant Genetic Resources Conservation and Utilization

Period Covered:09/2016 through 8/2017

Date of this Report:November 13, 2017

Annual Meeting Dates:June20-21, 2017

Participants:

Minutes:

Accomplishments and Impacts:

Plant Genetic Resources Conservation Unit

Plant genetic resources acquired from throughout the world are valuable sources of genetic diversity for use in scientific research, education, and crop improvement programs in the U.S. The project acquires, characterizes, conserves, evaluates, documents, and distributes genetic resources of agronomic and horticultural crops including sorghum, peanut, vegetables, subtropical and tropical legumes, warm-season grasses, cowpeas, annual clovers, industrial crops, other crops, and their crop wild relatives. The objectives of this project are to acquire, conserve, regenerate, back up, and distribute plant genetic resources with associated information for crops and crop wild relatives in the collection; conduct genetic characterizations and phenotypic evaluations of crops and crop wild relatives for priority genetic and agronomic traits; and to develop and update best management practices to ensure efficient plant genetic resource conservation. Seed and clonal genetic resources conserved and distributed by this project will provide researchers with a broad range of well-characterized crop and crop wild relative genetic diversity to use for research, evaluation, or breeding projects. Priority acquisition of genetic resources not represented in the collection are conducted to fill gaps in the collection and expand the genetic diversity of species within the repository. Additional characterization and evaluation of these genetic resources for priority molecular, morphological, and biochemical traits will enable researchers to efficiently identify specific accessions best able to meet their research, educational, and breeding needs.

Germplasm Maintenance and Distribution

A total of 96,577 accessions representing 1,603 plant species were conserved in the Griffin plant genetic resources collection. Of these, 86.4% were available for distribution to users and 96.9% were backed up for security at a second location. Seed samples for 80,287 accessions were conserved at -18°C for long-term storage. Germination testing has been conducted on 85,194 accessions (89.5% of collection) since 2002. Retesting of accessions stored in 2003-2004 was completed and begun for 2005 to determine the change in viability while stored in 4°C and -18°C freezer storage. A total of 43,372 seed and clonal accessions in 965 separate orders were distributed upon request to scientist’s and educators in 48 U.S. states and 43 foreign countries. Acquisitions made to the collection included 18 native legumes and 20 native warm season grass accessions. Seed regenerations and characterizations were conducted on 65 warm-season grass, 20 pepper, 15 watermelon, 12 squash and cucurbits, 10 other vegetable accessions, 506 cultivated peanut, 89 legume, industrial, and miscellaneous crop, 56 cowpea and other Vigna species, and 53 annual clover accessions. More than 816 sorghum accessions were regenerated in St. Croix. Forty pepper and watermelon accessions were regenerated and phenotyped by collaborators in Spain, ARS locations including Parlier, California, Charleston, South Carolina, and Mayaguez, Puerto Rico. Long term maintenance of 201 wild peanut, 419 warm season grass, 95 bamboo, and 6 Chinese water chestnuts was continued in the greenhouse or field. With cooperators in Parlier, California, 50 Vigna accessions have beenregenerated. A hydroponic system has been successfully used to regenerate 16 roselle accessionswith low seed numbers. A total of 729 sweetpotatoaccessions were maintained in tissue culture and backed-up in Ft. Collins, Colorado. Six accessions of pepper infected with Pepper Mild Mottle Virus were increased in the greenhouse and virus-free seed was produced for distribution to users.

Evaluation and Characterization

Seed from 325 watermelon accessions were evaluated for root growth characteristics in collaboration with ARSscientists at Charleston, South Carolina. Pollen from sweetpotato related species were examinedusing electron microscopy. Examination and characterization of watermelon interspecific hybrids for crop improvement continues. Collaboration with scientists at the International Potato Center in Lima,Peru for evaluating the use of molecular markers to assist in the identification of mis-identified sweetpotato accessions continued. A total of 769 and 1,846 cultivated peanut accessions from cold seed storage were evaluated for oil content and fatty acid composition, respectively. Three cultivated peanut accessionswere identified to contain a high concentration of oleate (averaging 80%), and molecular markers for the high oleate trait have been developed for peanut breeders to use. Oil content, fatty acid composition, and seed weight from 100 wild peanut accessions should be determined within a year. Collaborating with ARS scientists in Puerto Rico and Lubbock, Texas, an additional 320 sweet sorghum accessions have been evaluated for early-spring cold tolerance in lab conditions. More than 255 sorghum mutants generated using ethyl methanesulfonate-mutagenesis were sequenced and resulted in the identification of six abscisic acid insensitive mutants for potential environmental stress tolerance. A sesame mutagenesis project was continued with two M4 lines andthree M5 lines quantified for oleic and palmitic acid composition. Genetic diversity for seed traits and protein content in 111 cowpea core accessions from the 4°C cold storage was determined using principal component and cluster analysis. A first year crude protein evaluation of seed from 26 functional vegetable accessions including Vigna species, sesame, guar, and jute showed crude protein content ranging from 14-26%. Seeds from 8 field grown sesame accessions were evaluated for the nutritional compounds, sesamin and sesmolin with content ranging from 0.788-6.68 mg/g.

Specific Accomplishments:

• A total of 27 native grass accessions, including 20 switchgrass, six indiangrass, and one little bluestem, collected during plant exploration in Virginia, Maryland, Delaware, North Carolina, Virginia, and Georgia were cleaned, submitted to seed storage, and officially documented on GRIN. This germplasm increases the diversity of the collection and consists of native grass germplasm from geographic areas previously unavailable in the U.S. warm-season grass collection.
• As a step towards identifying pest and drought resistance genes for cultivar development in watermelon,genetic diversity in the desert watermelon (Citrullus colocynthis) and its relationship with Citrullus species was examined. Molecular and cluster analysis separated the desert watermelon into five groups and generally agreed with their geographic origins. Accessions of desert watermelon were successfully crossed with watermelon cultivars, and viable seeds were produced suggesting that desert watermelon is a viable source to introduce pest and drought resistant genes into cultivated watermelon.
• Functional guar accessions with high flavonoid content can be used as a functional health food. Immature pods from 19 guar accessions were examined for flavonoid concentrations over two years. The immature guar accessions produced flavonoid concentrations ranging from 0.49-468.3 µg/g. Plant Breeders and other scientists will use these accessions to improve the functional health traits in guar.

State Reports Submitted in July, 2017:

Alabama

According to records provided by S-9, a total of 457 accessions were sent to Alabama during 2013 to 2016. These requested germplasm cover 22 crops from 20 genera. They are watermelon, cultivated peanuts, peppers, sweet potato, mungbean, cowpea, sorghum, okra, legumes, bamboo, squash, water chestnut, nalta jute, grasses (warm season), hibiscus, sesame, eggplant, New Zealand spinach, and clover (annuals). The following table-1 summarizes numbers of required accessions by genus. The most requested crops were watermelon, cultivated peanuts, peppers, and sweet potato with 306, 55, 24, and 23 accessions, respectively. The recipients of required germplasm were university scientists, consultants, seed companies, gardeners and citizens of Alabama (table2). The largest number of accessions was requested by Dr. Srinivasa Mentreddy from Alabama A&M University for watermelon in 2014 (146 accessions) and by Dr. Abburi Lavanya in 2015 (150 Accessions). Besides Alabama A&M University, Dr. Guohao He from Tuskegee University requested 56 accessions of cultivated peanuts and wild relatives for his peanut genetics and genomics research in 2016. Dr. H. Mcbrayer from Auburn University and Alabama Cooperative Extension System requested a few accessions of watermelon as well as in 2016. Birmingham Botanical Gardens, Moundville Archaeological Park and Museum, Cahaba River Home School, Innovative Plants, LLC, Selected Plants, A Seed of Hope, Daybreak Farms, East Central Alabama Master Gardeners, Meals on Wheels, Regrow America, Rutledge Gardens, The Cat's Pyjamas, and Tierce Horseshoeing requested germplasm from the USDA-ARS Plant Genetic Resources Conservation Unit at Griffin, GA. Another 11 different individual people in AL received accessions from S-9 during 2013 to 2016, with several representing small farms.

In addition to the records provided by S-9, the peanut breeding program of Dr. Charles Chen at Auburn University is maintaining the purified accessions of the U.S. peanut mini-core collection (104 accessions) and conducting research in identifying loci contributing to desirable traits for cultivar development. A great effort of phenotyping the US peanut mini-core collection has achieved significant progress on identifying QTLs underlying TSWV (tomato spotted wilt virus) resistance, leaf spot resistance, peanut favor characters and chemistry. Dr. Chen distributed the seeds of the U.S. peanut mini-core collection to Dr. Thomas Isleib at North Carolina State University for screening Rhizoctonia solani resistances in greenhouse in 2016.

After Dr. David Weave retired from his cotton and soybean breeding program at Auburn University, Dr. Jenny Koebernick as a successor, continually runs the program starting in August of 2016. Dr. Koebernick’s lab focuses on 1) disease resistance breeding in cotton and soybean for target spot, fusarium wilt and reniform nematode et al., and 2) cultivar by management strategies for improving yield potential.

Table 1. Required Accessions by Genus

CROP / GENUS / TOTAL
Watermelon / Citrullus / 306
Peanuts (wilds)
Peanuts (cultivated) / Arachis / 55
Peppers / Capsicum / 24
Sweet potato / Ipomoea / 23
Vigna (mungbean)
Vigna (cowpea) / Vigna / 14
Sorghum / Sorghum / 11
Okra / Abelmoschus / 6
Legumes (special purpose) / Leucaena / 4
Bamboo / Phyllostachys / 3
Squash / Cucurbita / 2
Water chestnut / Eleocharis / 2
Nalta jute / Corchorus / 1
Grasses (warm season) / Dichanthelium / 1
Hibiscus / Hibiscus / 1
Sesame / Sesamum / 1
Eggplant / Solanum / 1
New Zealand Spinach / Tetragonia / 1
Clover (annuals) / Trifolium / 1
Year / University / Public Service/Primary Education / Private Sector / Total
2013 / 12 / 9 / 16 / 37
2014 / 149 / 18 / 8 / 175
2015 / 151 / 1 / 5 / 157
2016 / 65 / 2 / 21 / 88
Sub-Total / 377 / 30 / 50 / 457

Table 2. Required Accessions by Recipients

Georgia

During 2016, ninety-five different requests for plant germplasm were made to the S-009 unit by citizens of Georgia. As a result of these requests, 464 plant accessions were supplied to University scientists, USDA scientists, consultants, seed companies, gardeners, educators, and citizens of Georgia. The most requested crops were warm-season grasses, annual clover, sorghum, lespedeza, and peanut.

The University of Georgia maintains strong emphasis on plant breeding and continues to expand its advanced molecular biology programs. The Institute of Plant Breeding, Genetics, and Genomics currently has 37 total faculty members and 34 graduate students as well as many research scientists, and post-docs involved in various aspects of plant improvement. These programs supply new crop cultivars and associated technologies to our agricultural sector and rely heavily upon the plant materials maintained within the S-009 unit.

UGA currently has active cultivar development programs in soybean, peanut, small grains, cotton, turfgrass, forages, blueberry, pecan, grape, pepper, peach, watermelon, and numerous ornamental crops that frequently utilize the plant genetic resource collections. These cultivar development programs released 14 cultivars or crop germplasm lines during 2016 (Table 1).

Research programs in crop science, horticulture, plant pathology, entomology and other disciplines continue to utilize the genetic resources of the S-009 unit in both basic and applied research projects designed to address the needs of Georgia and U.S. agriculture.

Projects currently underway involving the S-009 germplasm include:

1)Evaluation of the available seashore paspalum (warm-season turfgrass) collection for salt tolerance and the development of molecular markers that could be used by breeding programs to improve salt tolerance in grasses.

2)Evaluation of seashore paspalum assessions for tolerance to dollar spot disease (Sclerotinia homoeocarpa).

3)Evaluation of a portion of the zoysiagrass germplasm collection for salt tolerance.

4)Identification of genes and pathways involved in Cucurbit disease resistance.

5)Identification of QTLs associated with important traits in watermelon.

6)Translational genomics for enhancing disease resistance in plants, an internet-facilitated education program for training plant breeders.

7)Inheritance of P. capsici resistance in pepper.

8)Sequencing plant genomes in soybean, peanut, common bean, pigeonpea, chickpea, and seashore paspalum.

9)Genetic analysis of shattering of the sorghum inflorescence.

10)Transmission genetics of Sorghum halepense xS. bicolor crosses.

11)Genome-wide association study of sorghum growth and development.

12)Genetic diversity and population structure of finger millet.

13)Ploidy level and genetic diversity in the genusPaspalum, group Disticha

14) Natural variation in genes potentially involved in plant architecture and adaptation in switchgrass (Panicum virgatumL.

15) Evaluation of pigeon pea germplasm for wildlife applications.

16) Genomic approaches to capture novel alleles in cultivated peanut.

17) Translational genomics to reduce pre-harvest aflatoxin contamination of peanut.

18) Phenotyping and genotyping of RIL populations for gene discovery and marker development.

19) Improving peanut seed quality by molecular definition of stress thresholds permissive for aflatoxin contamination

In summary, the S-009 unit remains a critical component of our research and cultivar development programs in Georgia.

Guam

1. Evaluation of germplasm adaptation to Guam’s climate

i.Leafy lettuce(Lactucasativa)

Germplasm evaluation of lettuce cultivars is an on-going project at the University of Guam. Heat tolerance, slow bolting, and reduced bitterness are the main characteristics for germplasm selection. Twelve lettuce cultivars were evaluated in the aquaponics system at University of Guam Triton Farm to study their growth and harvest yield from April to June in 2016. Seven cultivars had green to light green leaves while five cultivars had red leaves, red with green hearts or red speckles on green leaves. After six weeks of cultivation, Cv. Tropicana, green cultivar, produced the heaviest head (536g fresh weight). Among greens, ‘Starfighter’ (431g) produced the second heaviest head, followed by ‘Nevada’ (331g), ‘Tango’ (285g), ‘Muir’ (243g), ‘Panisse’ (240g), and Adriana (204g). Red cultivars weighed ‘Red fire’ (281g), ‘Cherokee’ (274g), ‘Lollo Rossa’ (183g), ‘Mottistone’ (159g), and ‘Skyphos’ (127g). The project will be continued.

ii.Tomato (Solanum lycopersicum)

Eighteen tomato cultivars were studied at five commercial farms in Guam in Fall 2015 and continued to dry season of 2016 to determine resistant lines against Ageratum yellow vein virus (AYVV) by Dr. R. Schlub, Extension Plant Pathologist. This trial was a repeat of a 2014 trial. Multiple lines of viruses in addition to AYVV were found and continued to study identification of diseases.

iii. Sorrel or Roselle (Hibiscus sabdariffa)

Roselle (Hibiscus sabdariffa) was obtained from the University of the Virgin Islands. The project started with 11 lines. On June 8, 2016, 20 seeds of each variety were sowed. Out of the 11 lines, only seven germinated: ‘Unique Leaf 128,’ ‘100 Pink,’ ‘Black Open Fruit TTB,’ ‘245xTTB,’ ‘186316 Dark Red,’ ‘Standard Red Jak’ and ‘Day Neutral KDN.’ The cultivars that did not germinate were: ‘Large Fruit TTB,’ ‘Dwarf 97’ and ‘Striped.’ Seedlings of seven germlines were transplanted in Guam cobbly clay soil at Guam Agriculture Experiment Station Yigo Farm on June 30, 2016 to test the adaptability to Guam’s environment, maturity, plant size, color of calyx. ‘Day Neutral KDN’ was the first to produce calyx at 78 days after transplanting (DAT) while ‘Standard Red Jak did not produce calyx until 153 DAT. The rest of the cultivars took about 15 to 17 weeks (105 to 119 DAT) after transplanting to produce calyx. Color of calyx varied. ‘Unique Leaf 128’ produced a light green calyx and ‘100 Pink’ produced a bright red calyx. The other cultivars had dark red calyx. ‘Day Neutral KDN’ defoliated at 100 DAT which was two weeks after calyx formation. Major insects found in the trial were mealy bugs and aphids.

iv. Chinese kale (Brassicaoleracea)

A variety trial of four lines of Chinese kale were tested in March to June 2016 by Joseph Tuquero, Extension horticulturist at University of Guam. The experiment was conducted using randomized complete block design (RCB) with three replications in Guam cobbly clay soil at Guam Agriculture Experiment Station Yigo Farm. Cultivars evaluated were: ‘Peth Nam Eak,’ Yho Fa,’ ‘Emperor’ and ‘Green Leaf.’ Cultivar ‘Green Leaf’ matured early less than 30 days after transplanting (DAT), initiating flowers. However, this cultivar produced the least fresh weight as marketable yield. Three other cultivars produced about the same yield with the similar size as marketable vegetable at 54-57 DAT. Two insect pests, unidentified whitefly species (Family: Aleyrodidae) and diamondback moth (Plutellaxylostella) were observed. A fungal disease, Alternaria spp. was also observed.

v. Bell pepper (Capsicumannuum)

A variety trial of bell peppers was conducted during March to June 2016 by Joseph Tuquero, Extension horticulturist at University of Guam. The experiment was conducted using randomized complete block design (RCB) in Guam cobbly clay soil at Guam Agriculture Experiment Station Yigo Farm with three replications including five cultivars: ‘California Wonder,’ ‘King Arthur F1,’ ‘Intruder F1,’ ‘Chinese Giant’ and ‘Gourmet F1.’ Seedlings were transplanted on March 24, 2016 and growth characteristics were observed. Harvest yield was examined from May 19 to June 27, 2016. Green mature sized fruits were harvested for yield data. Attempts to harvest marketable yield of fully ripe fruits resulted in mostly diseased fruits due to anthracnose fruit rot. Insect infestation of thrips (Thrips spp.) and mite (Steneotarsonemuspallidus) were observed. Marketable fruits of all cultivars were slightly smaller than their respective advertised sizes in commercial seed catalogue. High temperature (32°C) and high humidity (80-100%) of Guam’s condition may have contributed to early maturity, small fruit size, and high incidence of anthracnose fruit rot. ‘Intruder F1,’ ‘King Arthur F1’ and ‘Chinese Giant’ had higher percentage of marketable yield than ‘California Wonder’ and ‘Gourmet F1.’