QTL detection for stickiness of cooked rice using recombinant inbred lines derived from crosses between japonica rice cultivars

Abstract

To establish a marker-assisted selection system for the eating quality of cooked rice, we performed quantitative trait locus (QTL) analysis using 188 recombinant inbred lines (RILs) derived from crosses of two japonica cultivars, 'Sakihikari' and 'Nipponbare'. The former has excellent eating quality with strong stickiness whereas the latter is less sticky. We evaluated the stickiness of cooked rice using a sensory test, as well as amylose content (AC), amylographic characteristics (AM), and days-to-heading of RILs, which affect stickiness, in 2005, 2006 and 2007, and used them for QTL analysis. Six QTLs for stickiness were identified on chromosomes 1, 3 (two QTLs), 6, 7 and 8. Of these, qST3-1 on the short arm of chromosome 3 was detected throughout the three-year experiments but the others were detected in one year only. We also mapped two QTLs for AC, 19 QTLs for AM, and three QTLs for days-to-heading. Stickiness of RILs was significantly correlated with AM, and several QTLs for AM were detected in the same QTL regions for stickiness. These results thus suggested that AM was important for the stickiness of RILs. The obtained QTL information is useful to identify DNA markers tightly linked to genes controlling eating quality.