Identification of wheat dwarfing genes Rht-B1b, Rht-D1b, Rht8 and their effects on plant height

Abstract

In order to identify the height reducing capability of dwarfing genes to hybrids, we detected the dwarfing genes (Rht-B1b, Rht-Dlb, and Rht8) of 26 wheat cultivars or advanced lines by using molecular markers. Eight dwarfer wheat materials were selected as female to cross with two tall Sichuan landraces (Chinese Spring and Yibinbaimaizi). Then the height of F1 plants was tested, and the height reduction percentages calculated. With the two results combined, the effect of dwarfing genes to hybrids was evaluated. The results showed the expression of dwarfing genes strongly affected by different backgrounds, since the height of F1 plants varied largely even if they had same female or male parents. In Xgwm261 loci, which was closely linked with Rht8 gene, three different fragments (174 bp, 192 bp and 210 bp, respectively) were amplified, with the 210 bp fragment showing the highest ratio (57.7%). Notably, one elite line, named CY925ai, composed of three dwarfing genes at the same time (Rht-B1b + Rht-D1b + Rht8), was detected. Because of its dwarf height (57.92 cm), high average height-reduction percentage (29.4%), as well as high resistance to yellow rust and good agronomic traits, it was recommended as a good parent for wheat dwarfing and semi-dwarfing breeding.