| Apparent amylose content (AAC), gel consistency (GC), and gelatinization temperature (GT) are recognized as the most important determinants of rice eating and cooking qualities. The contributions of major starch-synthesis genes to these three traits have been investigated in the three consecutive experiments. In an initial QTL mapping with 130 doubled haploid (DH) lines, derived from an inter-subspecific cross of'Nanjing11'/'Balilla', the major QTLs responsible for AAC, GC, and GT were coincided with the Wx (granule-bound starch synthase gene), Wx, and SssIIa (soluble starch synthase gene) loci, respectively. In the next experiment, the markers tagged to major starch-synthesis genes were developed and used to genotype each DH line. As shown, the Wx locus was a principal determinant for both AAC and GC, and could account for 58.5% and 38.9% of the phenotypic variations, respectively; while, the SssIIa locus was associated with GT, and could explain 25.5% of the observed variation. Eventually, a F2 population consisting of 501 individuals, derived from an inter-subspecific cross of the two sticky rice varieties'Suyunuo'and'Yangfunuo 4', was examined with the gene-tagged markers. In the absence of the Wx gene, no starch-synthesis genes investigated could dominate the GC variation, however, the Sss... |
