A Preliminary Analysis Of The Effects Of Different Wx Alleles On Rice Grain Quality

Rice is one of the important crops in world, and it’s quality will directly affect the value of their goods, while amylose content is a key factor affecting the quality of rice. The previous study had showed that the amylose is mainly synthesized by the Waxy (Wx) gene encoding the granule-bound starch synthase (GBSS). Wx gene had been found to exist in multiple alleles, and there presents difference of the amylose content between Wx alleles. Therefore, the present study carried out preliminary analyses to identify the effects of different Wx alleles on rice grain quality. The main results are as followings:(1) Through hybridization and backcrossing with the recurrent parents, fifteen backcross lines, which contains different Wx allele, were constructed. The molecular markers were used to select and identify the genotypes of these lines. After careful measurement of their grain qualities, the results showed that the Wx allelic variation had a certain impact on rice grain quality.(2) The results from amylose content analysis showed that the level of amylose in selected lines was close related to the variation of the Wx gene. Thus, the Wx allele could regulate the expression of amylose content, and is the major regulated gene for amylose content.(3) The gel consistance (GC) data showed that there was no significant correlation between the GC level and the difference of Wx allele. So, the Wx gene is not a necessarily major gene for regulating GC. But the GC might be regulated by the gene tightly linked to Wx locus.(4) The data of starch viscosity properties (RVA properties) showed that there was significant difference of the main characteristic value (BDV and SBV) among the different Wx alleles. Thus, the Wx locus might also be the major gene for regulating RVA profile.(5) The results from DSC measurement implied that there was a significant difference of the gelatinization tempature (GT) among the lines with different Wx alleles. So, GT is closely related to the expression of the amylose content, and also regulated by the Wx locus.