QTL Mapping for Milling Quality in Elite Western U.S. Rice Germplasm.

Rice (Oryza sativa L.) milling yield is a key export and domestic grain quality trait whose genetic control is poorly understood. To identify genomic regions influencing grain quality, quantitative trait locus (QTL) mapping was performed for quality-related traits including head-rice yield (HR) in 205 recombinant inbred lines (RILs) derived from a cross of L-204, a high-HR long-grain cultivar, with 01Y110, a low-HR advanced breeding line with high yield potential in the temperate U.S. rice-growing region. In replicated trials planted in California during 2007-2008, four QTLs carrying the HR-increasing allele from L204 and three from 01Y110 were consistently expressed. Multi-QTL models accounted for 30% of genetic variation for HR and up to 58% for other quality-related traits. Measures of kernel damage, though correlated with HR, were poor predictors of HR. Heading time, kernel dimension, apparent amylose content, and other highly heritable traits showed no correlation with HR. Stable QTLs for HR are likely to be revealed best by multienvironment experiments employing larger population sizes or more direct measurement of kernel structure and development traits involved in kernel breakage. [ABSTRACT FROM AUTHOR]