Wednesday, November 15, 2006

Genetic analysis of agronomic and grain quality traits in an Oryza sativa/Oryza nivara advanced backcross population.

Hesham A. Agrama1, Georgia Eizenga2, Rolfe J. Bryant2, Pericles C. F. Neves3, and David Mackill4. (1) Univ. of Arkansas Rice Research and Extension Center, 2900 Hwy 130 East, Stuttgart, AR 72160, (2) USDA-ARS DBNRRC, PO Box 1090 2890 Hwy. 130 E, PO Box 1090 2890 Hwy. 130 E, Stuttgart, AR 72160-1090, United States of America, (3) EMBRAPA Arroz e Feijao, C.P. 179, 75.375-000, Sto. Antonio de Goias-GO, Brazil, (4) IRRI, 6776 Ayala Avenue Suite 1009, 6776 Ayala Avenue Suite 1009, Makati City, PHILIPPINES

Rice wild relatives are a potential source of genetic diversity for cultivated rice improvement. Approximately 175 BC2F3:4 M202 (Oryza sativa L.) / O. nivara Sharma & Shastry (IRGC 100195) advanced backcross progeny were genotyped with 150 SSR (single sequence repeat) markers, and phenotyped for five agronomic and four grain quality traits. Quantitative trait loci (QTL) controlling these traits were identified using the software QTLNetwork. The SSR markers were distributed throughout the rice genome and mapped to chromosome location using the software JoinMap4. DNA markers, that were recently developed to identify grain quality traits in U.S. rice cultivars, were used to identify unique quality alleles contributed by the O. nivara parent. The O. nivara parent also contributed some positive alleles for improving agronomic traits thus; selected progeny will be excellent parents for improving U.S. rice varieties.