The Coding Regions Allelic Variations Of TaGw2-6A And The Relationship Between The Allele And Drought Tolerance Of Wheat(Triticum Aestivum L.)

Drought is one of the most significant factors that restrict wheat(Triticum aestivum L.) growth and reduce productivity. The kernel size and its stability affect the yield of wheat in different rainfalled locations. The research of grain weight and the relationship between the drought resistance has the vital significance to high yield and stable yield.An allelic variation with single T-base insertion at 977 bp of TaGW2-6A was detected in Lankaodali with large kernel, designated as TaGW2-6A-T(TT genotype), but was not found in Chinese Spring(tt genotype). According to the sequence of "T" insert,we designed primers to detect the coding regions allelic variations of TaGW2-6A by High Resolution Melting Curve(HRM) analysis technical, and the sequence of PCR products were analyzed. To gain further insight into the role of allelic variations of TaGW2 in drought tolerance, we analyzed various physiological parameters related to stress response and kernel weight related traits, including the chlorophyll fluorescence kinetics parameters, stem soluble sugar content, drought resistance index and kernel weight related traits, on 325 recombinant inbred lines(RILs) derived from a cross between Chinese Spring and Lankaodali under different water conditions in flowering, filling and milk stage. The results are as followed:1. Results showed that It was accurate to detect the wheat coding regions allelic variations of TaGW2-6A by HRM analysis technical, and classified as Lankaodali genotype(TT), Chinese Spring genotype(tt) and heterozygous genotype(Tt). The PCR product sequencing results showed that the solubility curve difference is caused by the "T" base insert.2. Compared to tt genotype, the kernel length, kernel width and kernel weight of TT and Tt genotype is increased significantly under drought stress, and the variability of kernel length, kernel width and kernel weight of TT genotype was smaller than that of RILs with tt genotype in Yangling and Qianxian.3. The chlorophyll fluorescence kinetics parameters of RILs and their parents reduced, except the initial fluorescence Fo under drought stress. The variability of chlorophyll fluorescence parameters of RILs with TT and Tt genotpye was smaller than that of RILs with tt genotype in Yangling and Qianxian.4. The stem soluble sugar content increased under drought stress, and the stem soluble sugar content of RILs with TT and Tt genotpye was bigger than that of RILs with tt genotype in Yangling and Qianxian. The AESSC and RFSSC increased with TT and Tt genotype, while decreased with tt genotype.5. The drought resistance index and stem soluble sugar content for two genotypes(TT and Tt genotype) were significant or extremely significant difference(P<0.05 or P<0.01), and the drought resistance index of TT genotype was close to Jinmai 47.6. In conclusion, TaGW2-6A variation(TT genotype) was better able to prevent reducing production in different locations with strong drought resistance and stable yield ability than wild-type(tt) plants. Taking full use of the genotype for high and stable yield is significant for wheat molecular breeding.