Effects of dwarfing genes on some agronomic characteristics of wheat.

To investigate the effects of dwarfing genes Rht-B1b,Rht-D1b and Rht8 on agronomic traits of wheat,we use molecular markers analysis combined with pedigree information,124 wheat cultivars widely used in Chinese major wheat production regions were classified into different categories based on the dwarf genes carried,then the effects of dwarf genes on plant height,length of flag leaf,spikes per individual and kernels per spike were analyzed based on these data from the field and root length data from the lab.Results indicated that(1)The screening of 124 varieties with molecular markers revealed that there were 23 genotypes with dwarfing gene Rht-B1b,7 genotypes with dwarfing gene Rht-D1b and 22 genotypes with dwarfing gene Rht8,and 34 genotypes with two dwarfing genes of Rht-B1b and Rht8,and 16 genotypes with two dwarfing genes of Rht-D1b and Rht8.(2)The effects of dwarfing genes Rht-B1b,Rht-D1b and Rht8 on agronomic traits of wheat showed that the strongest effect on reducing plant height was observed for dwarf genes Rht-D1b and Rht-B1b,and then Rht8,and no significant differences was observed in seedling root length;The length of flag leaf of wheat cultivars with Rht8 was significantly longer than that of other dwarfing genes;there were no significant differences observed in spikes per individual;the kernels number per spike of wheat cultivars with dwarfing genes Rht-D1b and Rht8 were significantly higher than that with dwarf gene Rht-B1b.To summarize,the dwarfing genes Rht-B1b and Rht-D1b shorten the flag leaf length largely while reducing plant height,the dwarfing gene Rht8 had much less negative effects on other agronomic traits and also could reduce plant height to some extent,meanwhile increasing grain number per spike.Rht8 is an ideal dwarfing gene for wheat improvement.