Evaluation of effects of Rht-b1a/b/e alleles by using the isogenic lines of bread winter wheat

Abstract

Rht-B1 is one of the most important genes responsible for the height of bread winter wheat (Triticum aestivum L.). Studies of dwarfing genes are crucial for both improving genetic potential of the bread wheat cultivar and developing new effective breeding strategies in conditions of insufficient moisture. In this study, tall isogenic lines containing wild type Rht-B1a allele (Odes'ka 267 and Odes'ka 51) and short ones containing Rht-B1b (Odes'ka 267 b ) and Rht-B1e (Odes'ka 51 e ) alleles was analysed. The aim of the experiment was to evaluate direct and pleiotropic effects of these alleles on main agronomic traits of winter wheat in the south steppe region of Ukraine. Methods used are allele-specific PCR, polyacrylamide gel electrophoresis (PAGE), structural analysis of main agronomic traits and statistical data processing. Effects of Rht-B1b and Rht-B1e alleles on important agronomic characteristics of winter wheat were evaluated and were found differences in their influence on such traits: plant height, thousand kernel weight, total protein content, absolute protein content of thousand kernels. Rht-B1e reduces plant height more dramatically than Rht-B1b: decrease in plant height was 40.0% and 17.6%, respectively. The negative effects of Rht-B1e are decline in number of fertile spikelets, number and weight of kernels in the main ear, thousand kernel weight, whereas in plants with Rht-B1b these traits were increased, compared to the Rht-B1a allele plants. Main spike density was decreased by both alleles, but for Rht-B1e the drop was bigger. Rht-B1e more essentially increased productive tillering than Rht-B1b. In drought conditions plants with Rht-B1e allele showed less productivity than those containing Rht-B1b compared to respective recurrent wild type allele lines.