Mapping of genes for cooking and eating qualities in Thai jasmine rice (KDML105)

Thai jasmine rice, KDML 105, is known as the best quality rice. It is known not only for its aroma but also for its good cooking and eating qualities. Amylose content (AC), gel consistency (GC) and gelatinization temperature (GT) are important traits determining rice quality. A population of recombi nant inbred lines (RIL) derived from KDML105xCT9993 cross was used to study the genetic control of AC, GC and GT traits. A total of 191 markers were u sed in the linkage map construction. The 1605.3 cM linkage map covering nea rly the whole rice genome was used for QTL (define QTL) analysis. Four QTLs for AC were detected on chromosomes 3, 4, 6 and 7. These QTLs accounted fo r 80% of phenotypic variation explained (PVE) in AC. The presence of one ma jor gene as well as several modifiers was responsible for the expression of the trait. Two QTLs on chromosome 6 and one on chromosome 7 were detected for GC, which accounts for 57% of PVE. A single gene of major effect along with modifier genes controls GC from this cross. The QTLs in the vicinity o f waxy locus were major contributors in the expression of AC and GC. The fi nding that the position of QTLs for AC and GC were near each other may refl ect tight linkage or pleiotropy. Three QTLs were detected, one on chromosom e 2 and two on chromosome 6, which accounted for 67% of PVE in GT. Just lik e AC and GC, one major gene and modifier genes governed the variation in GT resulting from the KDML105xCT9993 cross. Breeding for cooking and eating q ualities will largely rely on the preferences of the end users.