| In the breeding practice of using Indica-Japonica Hybrid Rice to produce fine japonica rice,the chalkiness of the developed japonica rice increased significantly due to the infiltration of the pedigree relationship between Indica and japonica rice.In order to clarify the genetic basis of chalky traits in Indica rice,In this study,low chalkiness and high quality japonica rice K1240 was used as background,high yield and good high chalkiness indica TN013 chromosome segment substitution lines of the 40 families as test materials(KT)to development of genetic mapping analysis and environmental interaction analysisKT families and their parents were planted in Hainan,Beijing and Shenyang respectively.Under different ecological environments,the chalkiness rate was significantly higher than that of the background parent K1240,and the chromosome fragments affecting the chalkiness traits were determined.At the same time,the stability of chromosome fragments related to chalky grain rate in different environments was investigated to distinguish between environmentally sensitive and environmentally sensitive fragments.Then the factors affecting chalkiness were analyzed according to the selected stable high-chalkiness families,including the ratio of grain length to width,the expression of key genes of amylase synthase during grain filling,and the spatial distribution of starch grains in late maturity,and then the factors affecting the chalkiness were comprehensively analyzed.The results showed that:1.The KT population of fragment substitution lines used in this study was found to be significantly higher than that of the control background parent K1240 in three different ecological environments,Hainan,Beijing and Shenyang.There are five high-chalky families in Hainan.The infiltration fragments are distributed on chromosomes 8,9,10,11 and 12.There are 7 distinct high-chalky families in Beijing.The infiltration fragments are distributed on chromosomes 1,2,5,9,10,11 and 12.There are 7 high-chalky families in Shenyang.The infiltration fragments are distributed on chromosomes 2,5,8,9,10,11 and 12.Among them,kt37 was stable in all three environments,which was significantly higher than other families and Japonica rice parents K1240.It is suggested that the introgressive fragment of chromosome 12 of kt37 family has the main chalkiness-producing gene.2.By measuring the grain type of the CSSL population in Hainan,Beijing and Shenyang,and analyzing the correlation between the chalkiness rate of rice in the same area,it was found that there was no correlation between the grain type and the chalkiness rate value of the CSSL population.It was considered that the chalkiness rate value of the CSSL population was not affected by the grain length-width ratio,but was caused by other genetic factors.3.Samples from kt37 families were taken at milk,wax and yellow filling stages to investigate the expression of starch synthase-related genes.The results showed that the high expression of starch synthase-related genes during wax ripening stage played an important role in the formation of chalkiness,and its effect was also reflected in the combination of amylose and amylopectin with the synthesis and metabolism of adenosine diphosphate glucose formed by starch precursors.Metabolism.Further analysis showed that the upstream key genes controlling the formation of chalkiness significantly enhanced amylose formation while regulating the formation of chalkiness.4.Ultrastructural observation on cross sections of rice grains of selected kt37 family materials and recipient parent K1240 showed that there were significant differences in starch grain shape,size and spatial arrangement between high chalkiness material kt37 and recipient parent.This indicated that the target functional gene of Indica Rice in this chromosome interval formed chalkiness by regulating the starch structure of endosperm. |
PDF Full Text Request