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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION, CHARACTERIZATION, AND EVALUATION OF CROP GENETIC RESOURCES AND ASSOCIATED INFORMATION
2012 Annual Report


1a.Objectives (from AD-416):
Strategically expand the genetic diversity in genebank collections and improve associated information for priority vegetable, sorghum, peanut, subtropical/tropical legume, and warm-season grass genetic resources. Conserve and regenerate priority vegetable, sorghum, peanut, subtropical/tropical legume, new crop, and warm-season grass genetic resources efficiently and effectively, and distribute pathogen-tested samples and associated information worldwide. Strategically characterize (“genotype”) and evaluate (“phenotype”) priority vegetable, sorghum, peanut, subtropical/tropical legume, and warm-season grass genetic resources for molecular markers, morphological descriptors, and key agronomic or horticultural traits such as biochemical content and product quality. Conserve, regenerate, and distribute germplasm of specialty crops, current or potential bioenergy crops (e.g., sweet sorghum, switch grass, and Miscanthus), and new genetic stocks generated by genomic research (e.g., assocition mapping projects) with sorghum and other crops.


1b.Approach (from AD-416):
Acquire samples of native warm-season grasses, bioenergy crops, subtropical legumes, Ipomoea species, chile pepper, and annual clovers to fill current gaps in NPGS collections. Survey existing holdings of sorghum genetic stocks, identify material that would fill gaps in NPGS collections, and begin acquiring and characterizing them. Conserve and distribute genomic research genetic stocks including association mapping populations of sorghum and other crops. Regenerate, conserve, and distribute more than 88,000 accessions of specialty crops, bioenergy crops, and other priority genetic resources and associated information. Increase the number of sweetpotato and warm-season grass clonal accessions maintained in tissue culture. Increase to 95 percent the proportion of the collection backed up at second sites. Develop superior regeneration methods for seed and clonally-propagated crops. Assay stored genetic resources for vigor, viability, and health. Distribute on request accessions and information that meet the specific needs of researchers and breeders. Develop and apply new genetic markers for phylogenetic and genetic diversity analyses of priority crops. Update and apply phenotypic descriptors for vegetables, peanuts, warm-season grasses, and subtropical/tropical legumes. Develop, enhance, and/or apply high performance liquid chromatography (HPLC) procedures for analyzing variation in flavonoids, antioxidants, capsaicin, and other key phytochemicals in accessions. Incorporate characterization, phenotypic, and biochemical data into GRIN and/or other databases.


3.Progress Report:
A total of 91,259 accessions of 1,548 plant species were maintained in the Griffin plant genetic resources collection. Over 87.8% of accessions were available for distribution to users and over 97.2% were backed up for security at a second location. Bulk seed samples for 67,241 accessions were maintained at -18 C for long-term storage with seed of the remaining accessions stored at 4 C. A total of 32,512 seed and clonal accessions in 946 separate orders were distributed upon request to scientists and educators in 47 U.S. states and 45 foreign countries. Acquisitions made to the collection included 176 sorghum, 230 pepper, 90 warm-season grass, 32 cowpea, 12 peanut, 13 vegetable, and 10 other accessions. A plant collection trip in Alabama, Florida, Georgia, and South Carolina added 39 naturalized Sorghum halepense, 14 switchgrass, and 3 indiangrass accessions to the collection. Seed regenerations and characterization were conducted on 815 peanut, 77 cowpea, 113 warm-season grass, 150 pepper, 301 legume, new, and misc. crop, 127 annual clover, and 32 other vegetable accessions. Peanut accessions were regenerated with cooperators in Georgia, Florida, North Carolina, Oklahoma, and New Mexico. Over 200 pepper accessions were grown in California for characterization and recording of digital images. Digital images of sorghum, cucurbit, cowpea and warm-season grass accessions, and seed oil and fatty acid content of okra and watermelon, peanut core fatty acid content, and sorghum 100-seed weight data were added to the Germplasm Resources Information Network (GRIN). Long-term maintenance of 242 wild peanut and 411 warm-season grass clonal accessions was continued in the greenhouse with an additional 47 napiergrass accessions maintained in the field. A total of 24 bermudagrass and 725 sweetpotato accessions were maintained in tissue culture. Germination testing has been conducted on 73,274 accessions (over 81% of collection) since 2002. In cooperation with industry, differential sets of four vegetable crops were distributed to researchers for identification of disease races. Photoperiod-sensitive Teramnus and annual clover accessions were regenerated in the winter greenhouse. Seed oil content and fatty acid composition was determined for the entire U.S. collections of kenaf, roselle, okra (oil content only), and two pumpkin species. Morphological descriptor, oil content, fatty acid composition, and genetic variability data are being used to develop a core subset from the U.S. castor bean collection. With cooperators in Kansas, a total of 300 sorghum accessions were selected for biomass evaluation in the field from 1,000 accessions genotyped by genotyping-by-sequencing (GBS) analysis. Variation for phytochemicals including flavonol content, oil content, fatty acid composition, and anthocyanin index were determined in lablab, desmodium, roselle, and/or kenaf accessions. Variation in glucose content was found in sunn hemp accessions. Six clonal little bluestem lines were evaluated in the field for ornamental cultivar development. Salt tolerance screening was conducted on the U.S. zoysia collection.


4.Accomplishments
1. Improved Storage of Plant Genetic Resources. Most plant genetic resources are maintained under short-term (4C) rather than long-term (-18C) storage temperatures, which increases the need for frequent seed regeneration that can reduce genetic variability. ARS researchers at Griffin, GA, split seed samples of over 67,000 accessions (75% of the collection) with the bulk of each accession placed in -18C long-term storage. New storage facilities will enable most seed of the entire collection at Griffin to be stored in long-term storage. These plant genetic resources will remain viable longer with reduced need for regeneration and better retention of genetic variability of the original sample for users.

2. Oil and Fatty Acid Content of Two Pumpkin Species. Pumpkin species are widely cultivated for seed that produces a high quality oil, however, little information is available on species variability for seed oil content or composition. ARS researchers at Griffin, GA, determined that average oil content was similar in two pumpkin species, but one subspecies (Cucurbita argyrosperma subsp. argyrosperma var. callicarpa) had greater seed oil content than others evaluated. Linoleic acid was identified as the predominant fatty acid in all samples analyzed of the two pumpkin species. These accessions will be used by researchers interested in developing pumpkin cultivars as an oil seed crop.

3. High Oleic Acid Detection in Peanut. The high oleic acid trait in peanut is an important seed quality trait of great interest in peanut cultivar development. ARS researchers at Griffin, GA, compared three different methods used by researchers to detect the high oleic acid trait. The genotyping method and capillary electrophoresis method were the most compatible methods in detecting high oleic acid peanuts, while the near infrared method was not as effective. These data provide information on the accuracy of high oleic acid detection for breeders who employ different platforms for detection.

4. Oil and Fatty Acid Content of Nine Chili Pepper Species. Chili peppers are cultivated primarily for their fresh fruit; however, a market exists for the oil extracted from pepper seed. Little information is available on variability among the various types and species of chili pepper for the amount of oil present in seed or the composition of the oil. ARS researchers at Griffin, GA, found that seed oil content varied greatly from 11 to 36% among 250 accessions of nine chili pepper species, with Capsicum annum having higher average seed oil content than other species. Linoleic acid was the predominant fatty acid present in seed of all species, though differences in seed fatty acid composition among species were observed. These results will facilitate research exploring the potential of chili pepper as an oil seed crop.

5. Acquisition of Native Warm-Season Grass Accessions. Native warm-season grasses are currently of interest to users for habitat restoration, biofuel use, or ornamental use. ARS researchers in Griffin, GA, acquired 90 native switchgrass, deertongue, Florida paspalum, indiangrass, and sea oats accessions for the U.S. warm-season grass collection. These grasses will provide users with greater genetic variaibilty needed for their breeding and research program.

6. Seed Oil and Fatty Acid Content of U.S. Collection of Hibiscus. A number of oil seed crops are under evaluation for potential biofuel or bioproducts use, however little information is available on the genetic variability for oil content among plant genetic resources of these crops. ARS researchers at Griffin, GA, identified two accessions from 329 Hibiscus accessions with higher oil content of over 22%. Also, one Hibiscus accession was identified with much greater vernolic acid content, which may be used for industrial oil production. These accessions have potential for breeding Hibiscus with greater, high quality oil production for use in developing new bioproducts.


Review Publications
Wang, M.L., Raymer, P., Chinnan, M., Pittman, R.N. 2012. Screening of the US peanut germplasm for oil content and fatty acid composition. Biomass and Bioenergy. 39:336-343.

Barkley, N.L., Pinnow, D.L., Wang, M.L., Ling, K., Jarret, R.L. 2011. Detection and classification of SPLCV isolates in the U.S. sweetpotato germplasm collection via a real-time PCR assay and phylogenetic analysis. Plant Disease. 95(11):1385-1391.

Jenkins, T.M., Wang, M.L., Barkley, N.L. 2012. Microsatellite markers in plants and insects part II: Databases and in silico tools for microsatellite mining and analyzing population genetic stratification. Genes, Genomes, and Genomics. 6(1):60-75.

Wang, M.L., Chen, C.Y., Pinnow, D.L., Barkley, N.L., Pittman, R.N., Lamb, M.C., Pederson, G.A. 2012. Seed dormancy variability in the U.S. peanut mini-core collection. Research Journal of Seed Science. 5:84-95.

Jarret, R.L., Levy, I. 2012. Oil and fatty acid content in seed of Citrullus lanatus Schrad. Journal of Agricultural and Food Chemistry. 60(20):5199-5204.

Wu, Y., Li, X., Xiang, W., Zhu, C., Lin, Z., Wu, Y., Li, J., Pandravada, S., Ridder, D., Bai, G., Wang, M.L., Trick, H., Bean, S., Tuinstra, M., Tesso, T., Yu, J. 2012. Presence of tannins in sorghum grains is conditioned by different natural allels of Tan1. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1201700109/-/DCSupplemental.

Wang, M.L., Morris, J.B., Tonnis, B.D., Davis, J., Pederson, G.A. 2012. Assessment of oil content and fatty acid composition variability in two economically important Hibiscus species. Journal of Agricultural and Food Chemistry. 60:6620-6626.

Fountain, J.C., Qin, H., Chen, C.Y., Dang, P.M., Wang, M.L., Guo, B. 2011. A note on development of a low-cost and high throughput SSR-based genotyping method in peanut (Arachis hypoghea L.). Peanut Science. 38:122-127.

Lin, Z., Li, X., Shannon, L.M., Yeh, C., Wang, M.L., Bai, G., Peng, Z., Li, J., Trick, H.N., Clemente, T.E., Doebley, J., Schnable, P.S., Tuinstra, M.R., Tesso, T.T., White, F., Yu, J. 2012. Parallel domestication of the Shattering1 genes in cereals. Nature Genetics. 44:720-724.

Xin, Z., Wang, M.L. 2011. Sorghum as a versatile feedstock for bioenergy production. Biofuels. 2(5):577-588.

Morris, J.B., Hellier, B.C., Connett, J.F. 2011. Medicinal properties of legumes. In: Singh, R., editor. Genetic Resources, Chromosome Engineering, and Crop Improvement Medicinal Plants. Vol.6. Urbana,IL:CRC Press. p.297-396.

Morris, J.B. 2011. Christmas-candle Senna:An ornamental and pharmaceutical plant. In: Singh R., editor. Genetic Resources, Chromosome Engineering, and Crop Improvement Medicinal Plants. Vol.6. Urbana,IL:CRC Press. p.793

Morris, J.B., Wang, M.L., Thomas, T. 2012. Quercetin, kaempferol, myricetin, and fatty acid content among several Hibiscus sabdariffa accession calyces based on maturity in a greenhouse. In: Chikamatsu, T., Hida, Y., editors. Quercetin: Dietary sources, functions and health benefits. Hauppauge,NY:Nova Science Publishers. p.269-282.

Mosjidis, J.A., Wang, M.L. 2011. Crotalaria. In: Chittaranjan, K.,editor. Wild Crop Relatives:Genomic and Breeding Resources Industrial Crops. 1st edition. New York,NY:Springer. p.63-69.

Last Modified: 12/22/2014
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