• Responsible for US rice germplasm regeneration, evaluation, and enhancement, along with collection of  data for inclusion into the Germplasm Resource Information Network (GRIN)
• Cooperate with other scientists to foster international exchange of rice germplasm, especially with major rice growing nations in Asia, with IRRI, and with other Consultative Group for International Agricultural Research (CGIAR) centers
• Assess rice germplasm needs for the US, and attempt to fill existing gaps by germplasm exchanges with international research centers and scientists
• Coordinate national efforts for US rice germplasm evaluation and enhancement
• Conduct research for identifying special gene(s) beneficial to US rice industry, and improving rice germplasm to meet the needs of US rice industry
• In cooperation with the National Small Grains Collection (NSGC) at Aberdeen, Idaho, increase seed stocks of new introductions to the US germplasm system following APHIS quarantine evaluation

Research Achievements and Service Activities in 2007

Research:

1. Genotyping core subset: The USDA rice core subset, including 1794 accessions from 114 countries, was characterized with 75 SSR markers covering the entire genome about every 30 cM. Along with 26 phenotypic traits evaluated previously, the molecular data will be used for association mapping analyses and assessment of genetic diversity of some 20,000 accessions managed by the National Small Grains Collection (NSGC).

2. Mining novel blast resistance gene(s): Established two mapping populations, identified 118 polymorphic SSR markers between parents for one and 108 for another population and phenotyped 700 progenies in the populations with blast race IE-1k that overcomes the resistance conveyed by the Pi-ta gene, a major-resistance gene that is widely used in the US rice industry.

3. Developing DNA markers for straighthead resistance: Identified two SSR markers associated with straighthead resistance in the USDA rice core collection, phenotyped 600 F2 progenies in two populations, prepared plant tissue of the progenies for DNA analysis, and established 560 F8 recombined inbred lines (RIL) in the two populations for further study.

4. Lowering arsenic (As) content in rice grain: Identified dramatic differences in grain As in the USDA rice germplasm collection and determined that grain As is further reduced with proper water- management in the field. The discoveries open an opportunity to reduce grain As by either improved cultivars bred from the identified germplasm or by field management practices.

5. Cooperative achievements: 1) Discovery of mutation for controlling bran color with ARS co-worker: Brooks et al. A natural mutation in rc reverts white-rice-pericap to red and results in a new, dominant, wild-type allele: Rc-g. Theor. Appl. Genet. (Accepted) 2008; 2) Heterosis study with Chinese Academy of Sciences: Tu et al. Production and heterosis analysis of rice autotetraploid hybrids. Crop Sci. 47:2356-2363, 2007; 3) Cytogenetics study with Chinese Academy of Sciences: Luan et al. Cytogenetic study on two F1 hybrids of autotetraploid rice varieties showing extremely high level of heterosis. Plant Systematics and Evolution, 267:205-213, 2007; and 4) Pre-harvest sprouting with Sichuan Academy of Agricultural Sciences in China: Gao et al. QTL analysis for resistance to pre-harvest sprouting in rice (Oryza sativa). Plant Breed., 127:268-273, 2008.

Service:

1. Germplasm rejuvenation: In 2007, rejuvenated 2,288 accessions including 2,058 stored in the NSGC for 20 years or more.

2. Germplasm evaluation: Prepared panicle samples of the 2,288 accessions for image recording by the NSGC and provided 20,768 data points for entering into GRIN, including descriptors of maturity, plant height, plant type, panicle type, lodging, awn type, rough rice color and kernel length, width, L/W ratio and weight, and brown rice color and kernel length, width, L/W ratio and weight, amylose content, and alkali spreading value.

3. Public seed-distribution of core collection: Distributed 9,406 accessions to 15 national and international research groups.

4. Public seed-distribution of enhanced germplasm: Distributed over 4,000 kg of seed of improved germplasm lines to 47 requesters from universities, private companies, rice producers and federal agencies.

5. Genetic Stocks – Oryza (GSOR) Collection: In 2007, added 2,080 accessions to the collection including a mapping population and purified seed of the USDA rice core collection, which increased the current collection to 23,097 accessions. Distributed 2,724 accessions to 45 domestic requesters and 6 international researchers. GSOR Website Link.

Personnel