Effectiveness of Lr34 gene in reducing leaf rust severity in wheat cultivar BRW 934 transferred through marker-assisted backcross

Abstract

Leaf rust caused by Puccinia triticina Eriks. is one of the yield constraining diseases of wheat. It is prevalent in almost all wheat growing areas of the world. Durable leaf rust resistance conferred by integration of slow rusting and effective major genes is the best strategy to combat this disease. In the present study a slow rusting gene, Lr34 was transferred into a heat tolerant wheat variety BRW 934 using marker-assisted back crossing. The BRW 934 was found highly susceptible to several Indian pathotypes of P. triticina including 12–2, 77–1, 77–5, 77–7, 77–8, 77–9, 77–10 and 104–2. The selection of the Lr34 gene was carried out using STS (sequence tagged site) marker csLV34. BC₁F₁ plants carrying Lr34 gene showed leaf rust scores ranging from 5 to 20MR and rust score in the BRW 934 progenies without the Lr34 gene were 30S-100S. Presence of the Lr34 gene significantly reduced disease severity in the progenies. Maximum recovery (87.5%) of the recurrent parent genome was obtained in plant number 16 and 30 in the BC₁F₁ generation. These findings indicated that the Lr34 gene can be effectively used in developing leaf rust resistant wheat lines for the Eastern-Gangetic plains.