Identification, fine mapping and characterization of Rht-dp, a recessive wheat dwarfing (reduced height) gene derived from Triticum polonicum

Abstract

Semi-dwarfism is an agronomically important trait in breeding for resistance to damage by wind and rain (lodging resistance) and for stable high yields. Dwarf Polish wheat (Triticum polonicum L., 2n = 4x = 28, AABB AS304) is a potential donor of dwarfing and other traits for common wheat improvement. A genetic analysis using an F2 population derived from a cross of AS304 and tall cultivar AS302 and derived F2:3 lines indicated that AS304 carries a recessive dwarfing gene, temporarily designated Rht-dp. Molecular markers and bulked segregant analysis were used to characterize and map the gene. Eight polymorphic SSR markers (Xwmc511, Xgwm495, Xgwm113, Xgwm192, Xgpw7026, Xgpw3017, Xgpw1108 and Xgpw7521) on chromosome arm 4BS and two AFLP markers (M8/E5 and M4/E3) were mapped relative to the dwarfing locus. The closest linked markers, Xgpw3017 and M8/E5 at 0.5 and 3.5 cM, respectively, from Rht-dp will enable its marker assisted transfer to wheat breeding populations. Allelic tests indicated that Rht-dp was allelic to Rht-B1b; hence it may be an alternative allele at the Rht-B1 locus.