Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 1, 2005
Publication Date: January 1, 2006
Citation: Kepiro, J.L., Fjellstrom, R.G., McClung, A.M. 2006. QTLs for milling yield in tropical Japonica long grain rice [abstract]. Plant and Animal Genome Conference Proceedings. p. 162.
Milling yield, defined as the percentage of whole rice kernels recovered after de-hulling rough rice and milling, is a critically important trait in rice. Milling yields vary considerably between cultivars, with low milling cultivars being rejected by rice growers. The cultivar Cypress, well-known for high and stable milling yield over a wide range of harvest moisture levels, was crossed with the cultivar Panda, characterized by low milling yield to produce 155 F11 progeny lines that were evaluated over two years for milling yield QTL identification. A WinSeedle color image analysis system allowed collection of data for kernel length, width, percent chalkiness, and percent green. Regression analysis indicated that 20.4 percent, and 12.1 percent of the variance in milling yield could be explained by chalkiness and green kernels, respectively, and these traits were independent of one another. Rough rice samples were re-wetted and dried to identify resistance to moisture induced grain fissuring which commonly occurs in the field. A milling yield reduction of 15.8 percent due to fissuring was associated with increased kernel width. We scored 684 polymorphic AFLP markers in the 155 lines and used 43 SSR markers of known location to anchor the AFLP markers onto the rice chromosomes. We have identified QTLs with highly significant linkage to length, width, and green kernels and others with weaker linkage to chalkiness. Molecular markers linked to these traits will permit early and efficient selection for high milling yield in populations under development for commercial release.