QTL analysis of percentage of grains with chalkiness in Japonica rice (Oryza sativa)

Appearance quality of rice grains is a major problem for rice production in many areas of the world. We conducted a molecular marker-based genetic analysis of percentage of grains with chalkiness (PGWC), which is a determining factor for appearance quality; it strongly affects milling, eating and cooking quality. An F(8) recombinant inbred line population, which consists of 261 lines derived from a cross between Koshihikari (Japonica) and C602 (Japonica), was used for QTL mapping. Three QTLs related to PGWC were detected on chromosomes 5, 8 and 10, together explaining 50.8% of the genetic variation. The 'Koshihikari' alleles qJPGC-5, qJPGC-8 and the 'C602' alleles at qJPGC-10 were associated with reduced PGWC. The QTL contributions to phenotypic variance were 18.2, 9.6 and 25%, respectively. These QTL markers for PGWC could be used for developing improved varieties.