Association Mapping Of Starch Quality With Starch Biosynthesizing Genes In Waxy Rice (Oryza Sativa L)

The development of social economy is boosting demands for better quality rice. Though glutinous rice (or waxy rice) is not suitable for staple food, it is popularly used for traditional food processing, such as brewing, pastry, and other foodstuffs. Therefore, to improve the quality of glutinous rice becomes more valuable than to increase its yield as compared to non-glutinous rice.In this study,50glutinous rice accessions were collected, and the genotypes of18starch bio synthesizing genes were analyzed by using36gene-specific molecular markers. Association analysis was carried out between the starch gene marker and starch quality trait to explore the formation mechanism influencing starch quality of glutinous rice. Our study could provide a genetic basis for potentially improving the quality of glutinous rice. The main results are summarized as follow:1. With all36gene-specific markers, each produced polymorphic alleles with the polymorphic information content ranging from0.0348to0.5409. Cluster analysis based on these markers revealed two groups representing indica and japonica rice, indicating that the starch genes in rice genome have already diverged into indica and japonica subspecies.2. The association analysis results showed that there are eight genes significantly associated (P<0.05) with starch quality traits in the glutinous rice. They are AGPsma, GBSSⅡ, SSⅠ, SSⅡ-1, SSⅡ-3(SSⅡa), SBEI, SBE3, and ISA. Among them, SSⅡ-3and SSI have a greater impact on glutinous rice starch quality than the others.3. Gelatinisation temperature and retrogradation were mainly controlled by SSⅡ-3and SSI.The P value of SSⅠ is significantly higher than that of SSⅡ-3, indicating that SSⅡ-3is the main factor which determine gelatinisation and retrogradation properties of glutinous rice starch and the long-chain branching (12<DP<24) has a greater impact on the starch gelatinization temperature and retrogradation trait than short-chain.4. Association analysis for rapid visco analyzer profile (RVA profile) parameters showed that many genes were associated with them, indicating that the genetic mechanism of RVA profile parameters were quite complex. In addition, SBE3and ISA show significant associated with PV, SB and BD, which suggested that eating quality of glutinous rice is affected by its amylopectin fine structure.5. The16starch property parameters showed a wide range of gene interactions except for Δ Hg, BD and SB, indicating that the genetic mechanism of starch quality in glutinous rice is complex.