Mapping of genes for leaf and stem rust resistance in bread wheat genotype Selection 212

Abstract

Resistance genes for leaf and stem rusts in bread wheat line Selection212 are recessive in nature. Both leaf and stem rust resistance genes, named tentatively as LrSel212 and SrSel212, have been mapped to the short arm of chromosome 2B separated by genetic distance of 16.4 cM. Xwmc474 was the closest marker located between two genes, 5.6 cM proximal to LrSel212 and 10.8 cM distal to SrSel212. Leaf rust pathotype 77-5 is virulent to leaf rust resistance genes located on chromosome 2B viz., Lr13, Lr16, Lr23, Lr35 and Lr73, but avirulent to Selection212, suggesting that LrSel212 is distinct from these genes. Six stem rust resistance genes have been assigned to chromosome 2B viz., Sr19, Sr20, Sr23, Sr36, Sr39 and Sr40. Stem rust pathotype 40A used in genetic analysis was virulent to Sr19 and Sr20, but avirulent to Selection212; and the latter showed a significantly lower infection type in comparison to Sr39. Sr23 and Sr36 showed susceptibility to few other stem rust pathotypes to which Selection212 was resistant. While the response of Sr40 to Indian pathotypes of Pgt is not known, differences in the genetic distance and nature of inheritance between Selection212 and Sr40 indicate their distinct identity. However, test of allelism with Sr40 is required to confirm whether SrSel212 represents a different locus. Selection212 may be useful in broadening the genetic base of rust resistance in wheat.

From Genetic Maps to QTL Cloning: An Overview for Durum Wheat

“…Amongst the pathogens damaging durum wheat crops at the leaf and stem levels, rust pathogens are the most prevalent. This includes leaf rust ( Puccinia triticina ), stem rust ( P. graminis tritici ), and stripe rust ( P. striiformis ), causing losses of 15–20% worldwide [ 91 ]. To date, over 77 genes conferring resistance to leaf rust (Lr) have been characterized and localized to specific wheat chromosomes [ 92 ].…”