2007 Annual Report
1a.Objectives (from AD-416)
To develop early-maturing, production-efficent indica rice germplasm and also develop rice germplasm with improved and novel grain qualities by inducing mutants, identifying natural variants, and through innovative genetic methods. To introgress new genes for pest resistance and stress tolerance into cultivated rice from wild Oryza species. Evaluate germplasm and establish a Rice Genetic Stocks Collection.
1b.Approach (from AD-416)
Develop highly production-efficient indica rice germplasm with suitable grain quality for U.S. markets through hybridization of early maturing, production-efficient indicas from central China with late maturing indica germplasm from IRRI. Initial recombinants will be jointly selected for early maturity and 20-22% amylose content followed by yield and quality evaluations creating a foundation of adapted indica germplasm which then can be tested for quality assessments, including grain shape, milling percentage and cooking quality. Induced mutation will be used to select early maturing lines in the IRRI germplasm. Early maturity enhances water use, i.e. fewer days of irrigation are required. Other atrributes of indica germplasm are more disease- and insect-resistance in addition to straighthead resistance. Induced mutation will be used to look for additional low phytic acid mutants to complement the low phytic acid-1 mutant already in hand, in order to further reduce phytic acid. The creation of a U.S. rice oil market has led to interest in developing higher-oil and altered fatty acid composition mutants. Agronomic performance of the giant embryo mutants available from Japan and China, is suspect, so the existing genes will be studied in different genetic backgrounds, as well as through induced mutation in U.S. rice varieties. There will be additional focus on inducing agronomically suitable mutants for semidwarfism and early maturity in the "gold-standard" aromatic rices of the world, basmatis and jasmines. Also the unstudied amylopection component of starch will be characterized for amylopectin chain lengths in order to determine how this affects cooking quality. The small number (ca. 100) of available Oryza species assessions will be screened for pest resistance and stress tolerance characters for backcrossing into cultivated germplasm. A Rice Genetics Stocks collection will be established for for seed propagated rice mutants, including morphological, developmental, and metabolic characters. In addition it will provide speciality handling and evaluation for rice accessions that cannot be handled by the National Small Grains Collection at Aberdeen, ID.
Identification of novel resistance to rice blast disease:
Rice blast disease is one of the most damaging and prevalent diseases of rice in the southern US. Scientists at the Dale Bumpers National Rice Research Center in collaboration with researchers at the University of Arkansas, at Stuttgart, AR, screened the USDA rice germplasm collection and identified several cultivars from China, Philippines and Ivory Coast that were resistant to all races of blast currently found in the US. Furthermore, these resistant cultivars contain none of the known resistance genes found in the US gene pool. Identification of these novel genes will aid breeders to develop new rice cultivars that are resistant to blast disease which will enhance the security of rice production in the US. (NP301, Plant Genetic Resources, Genomics, and Genetic Improvement, Component 1. Plant and Microbial Resource Management, Problem Statement 1B: Assess the Systematic Relationships and Genetic Diversity of Crop Genetic Resources; and Component 3. Genetic Improvement of Crops. Problem Statement 3C: Germplasm Enhancement/Release of Improved Genetic Resources and Varieties)
Identification of sheath blight resistance in wild relatives of rice:
Few genes for sheath blight resistance have been identified in cultivated rice (O. sativa), but wild relatives of rice, Oryza spp., are a possible source of novel resistance genes. At the Dale Bumpers National Rice Research Center in Stuttgart, AR, seven sheath blight resistant Oryza spp. accessions were identified out of some 70 accessions, introgression lines, and cultivars. Further characterization of the sheath blight resistance in these Oryza spp. accessions will lead to incorporation of these new genes into adapted rice varieties that serve as an invaluable source of disease resistance for the U.S. rice industry. (NP301 Plant Genetic Resources, Genomics, and Genetic Improvement, Component 3. Genetic Improvement of Crops. Problem Statement 3B: Capitalizing on Untapped Genetic Diversity, and Problem Statement 3C: Germplasm Enhancement/Release of Improved Genetic Resources and Varieties)
5.Significant Activities that Support Special Target Populations
Two DB NRRC scientists, Drs. Bryant and Eizenga, serve on the advisory and project evaluation committees for the recently funded 1890 Capacity Building Grant entitled “Enhancing Laboratory Instrumentation for Experiential Learning in Teaching Post-harvest Physiology, Food Science and Plant Biochemistry” awarded to the Department of Agriculture, University of Arkansas at Pine Bluff (UAPB). Scientists will provide advisement on the new courses proposed, equipping of the laboratory, purchasing of books and journals, provide internships to qualified students, and participate in the final project evaluation.
|Number of new CRADAs and MTAs||5|
|Number of non-peer reviewed presentations and proceedings||6|
|Number of newspaper articles and other presentations for non-science audiences||3|
Gibbons, J.W., Moldenhauer, K.K., Gravois, K., Lee, F.N., Berhnhardt, J.L., Meullenet, J., Bryant, R.J., Norman, R.J., Cartwright, R., Anders, M., Taylor, K., Bulloch, J., Blocker, M.M. 2006. Registration of 'Medark' Rice. Crop Science. 46:2316-2317.
Gibbons, J.W., Moldenhauer, K.K., Gravois, K., Lee, F.N., Bernhardt, J.L., Meullenet, J.F., Bryant, R.J., Anders, M., Norman, R.J., Cartwright, K., Taylor, K., Bullock, J., Blocker, M.M. 2006. Registration of 'Cybonnet' Rice. Crop Science. 46:2317-2318.
Agrama, H.A., Eizenga, G.C., Yan, W. 2007. Association mapping of yield and its components in rice cultivars. Molecular Breeding 19:341-356.
Yan, W., Rutger, J.N., Bockelman, H.E., Fjellstrom, R.G., Chen, M.H., Tai, T., McClung, A.M. 2007. Development and evaluation of a core subset of the USDA rice (Oryza sativa L.) germplasm collection. Crop Science. 47(2):869-878.
Rutger, J.N., Bernhardt, L. 2007. Registration of four indica rice genetic stocks. Crop Science. 47:461-462.