ARS | Publication request: Oryza nivara, a wild relative of cultivated rice, is a source of genes for improving seedling vigor

Submitted to: Plant and Animal Genome
Publication Type: Proceedings/Symposium
Publication Acceptance Date: January 10, 2009
Publication Date: January 10, 2009
Citation: Eizenga, G.C., Neves, P.F., Agrama, H.A., Bryant, R.J., Mackill, D. 2009. Oryza nivara, a wild relative of cultivated rice, is a source of genes for improving seedling vigor. In: Proceedings of Plant and Animal Genome Conference, January 10-14-2009, San Diego, CA. P. 232.

Technical Abstract: Rice (Oryza sativa L.) wild relatives are a potential source of genetic diversity for cultivated rice improvement. An advanced backcross population was derived from the U.S. temperate japonica rice variety, M-202, a medium grain commercial cultivar grown in California, crossed with O. nivara Sharma & Shastry (IRGC 100195). The population of 181 BC2F3:4 progeny was genotyped with 137 polymorphic SSR markers and phenotyped for seedling vigor, agronomic, kernel, and grain quality traits. The SSRs were distributed throughout the rice genome and mapped to chromosome locations using JoinMap 4 software. Using Qgene software, the positive effects of the O. nivara parent were noted in traits that could improve seedling vigor by major QTLs associated with increased shoot length, coleoptile length, mesocotyl length and root length. The O. nivara parent also increased the number of panicles per plant but decreased the spikelets per plant and number of fertile spikelets as confirmed by the QTL analysis. Major QTLs were attributed to the O. nivara parent for increased days to flowering and plant height, considered undesirable traits in commercial cultivars. The O. nivara parent contributed to a major QTL on chromosome 1 for increased kernel length, thus increasing the kernel length/width ratio. The M-202 parent was responsible for the major QTLs associated with amylose content and alkali spreading value, common measurements of rice grain quality that map to chromosome 6, the location of major genes for starch synthesis. These results indicate selected lines from this population are beneficial for improving seedling vigor in M-202 and through crossing, other rice varieties.