Effects Of Exogenous IAA And 6-BA Treatment On Grain Weight And Filling Rate Of Different Allelic Variations Of TaGW2-6A In Wheat

The increasing population and the reduction of arable land lead to the most serious global problems of Food shortage.Wheat have being the most important food crop in China,and its constant yield has attracted much attention.As an important factor of wheat yield,grain weight has been a hot research topic in recent years.The gene of Ta GW2-6A has been successfully cloned in wheat,and it was found that grain width and grain weight were significantly increased when the inserted the mutation of "T" base.In recent years,studies on plant hormones and wheat grain development have never stopped.IAA can promote the accumulation of dry matter in grains,while CTK plays an important role in the proliferation of endosperm cells in grains.In this study,small-grain cultivar CSand its large-grain near-isogenic line NIL31 were used as experimental materials to treat with exogenous IAA and 6-BA at different stages,and their grain phenotypes and filling characteristics were analyzed.The aim of this study was to investigate the response trend of exogenous IAA and 6-BA to different alleles of Ta GW2-6A.The main results are as follows:1.At grain development stage,the results of IAA treatment showed that different alleles of Ta GW2-6A had the same response trend to IAA treatment.20 mg/L IAA treatment 1-3 days after anthesis could significantly increase grain length,grain width and grain weight,and significantly prolong the time of high-speed grain filling.These results indicated that IAA treatment could control grain size by affecting grain filling time and dry matter accumulation rate.2.At grain development stage,the results of exogenous 6-BA treatment showed that the response of different alleles of Ta GW2-6A to exogenous 6-BA treatment was different among genotypes.The use of exogenous 6-BA treatment in wild type(CS)significantly increased grain length,width and weight,and significantly increased the peak grain filling rate.When NIL31 was treated with exogenous 6-BA,the grain length,grain width,grain weight and grain filling rate were negatively regulated.The time difference of hormone treatment showed that exogenous 6-BA treatment might affect the number of endosperm cells in wheat grains with different alleles of Ta GW2-6A,thus regulating the size of grains.3.The results of exogenous hormone treatment showed that the response trend of Ta GW2-6A to IAA was the same,but to 6-BA was the opposite.Therefore,it is suggested that Ta GW2-6A allelic variation may be involved in the regulation of cytokinin related gene expression,so as to jointly regulate the grain size.