The Studying On The Relationship Between Photooxidation, Chlorophyll Content And Grain Weight, Grain Density Of Wheat And Developing Molecular Marker

Photooxidation not only reduces the yield of crop by decreasing the photosyntheticproductivity, but also produce a negative impact for the quality. Therefore, the study on thetolerance in photooxidation of crop is very important for the breeding practice of wheat. ARILs population derived from the cross the two parents HSM/Y8679and79breedingmaterial were selected in this research. The relationships between tolerance ofphotooxidation and grain weight, grain density were investigated, at the same time, therelationships between the chlorophyll content of flag leaf and grain weight were alsostudied, which was from the flowering stage to maturity of wheat. The QTLs controllingchlorophyll content in the stages of flowering and grain filling of wheat were analyzedusing the RILs population. In our research, the effect of the variation of BAS1(a keyenzyme of brass in steroid catabolism) on grain weight and density was also studied. Themain results are as follows:1. Based on the analysis of the two years2010and2011trails. The correlationbetween grain weight and grain density and photooxidation tolerance was not significant inthe RILs population and the group of breeding material in2010. But, The correlationbetween grain weight and grain density and photooxidation tolerance of grain filling stagewas significant in the RIL population in2011.2. The chlorophyll content of flag leaf before and after treatment by photooxidation inthe RILs population of flowering of the two years and grain filling of2011, the79breedingmaterial of flowering and grain filling of2010showed an significantly positive correlationwith grain filling and grain weight. Our results also showed that the chlorophyll content inthe stages of flowering and grain filling respectively had a tight correlation with grainweight in the RILs population of the two years2010and2011, as well as the total contentof chlorophyll and the decreasing rate of chlorophyll in the stages of flowering and grainfilling.3. In this study, a set of SSR markers linked to the loci for chlorophyll content in thetwo stages of flowering and grain filling were screened. QTL analysis indicated that thetwo loci (2AS and5AL) showed significant effects on the phenotypic variation ofchlorophyll content. The QTL on2AS linked to Gwm614and Barc212could explain26.8%-30.0%of the phenotypic variation. The other QTL was located on the5AL linked toBarc141and Barc165, which could explain27.8%-27.0%of the phenotypic variation. 4. Our results showed that the allelic variation in BAS1gene had a close relationshipwith grain weight and density of wheat respectively, which was confirmed by thesignificant correlation between them. From these results, the variation of BAS1had beenproved to have more distinct effect on the grain weight than grain density. The variation inBAS1also had a tight association with the chlorophyll content of flag leaf at the stages offlowering and grain filling, as well as the total content of whole filling stages.