Combined effects of Wx and SSIIa haplotypes on rice starch physicochemical properties

BACKGROUND Wx and SSIIa are central genes for determining starch physicochemical properties and rice endosperm starch is composed of linear amylose, which is entirely synthesized by granule bound starch synthase I (GBSSI, encoded by Wx) and branched amylopectin. In the present study, different haplotypes of rice were examined to investigate the combined effects of pivotal genes in the metabolic chain of starch, Wx and SSIIa. RESULTS Wx haplotypes differed in terms of apparent amylose content (AAC) and gel consistency (GC). The I‐3 [haplotype I (Int1T/Ex10C) of Wx and haplotype 3 (A‐G‐TT) of SSIIa] and the I‐4 combinations of rice had better eating and cooking qualities (ECQs) with lower AAC, lower gelatinization temperature (GT) and softer GC. CONCLUSION The characteristic parameters of Rapid Visco‐analyser (RVA) could distinguish differences in AAC and GC but not GT. The I‐3 and I‐4 haplotype combinations of Wx and SSIIa represent key targets for the production of rice with better ECQs. © 2016 Society of Chemical Industry