Marker assisted selection for downy mildew resistance in table grapes

Abstract

Downy mildew disease is one of the major risk factors for viticulture. It is mainly caused by fungus, affecting grapevine including berries and leaves. It is controlled by the repetitive applications of fungicides leading to pollution, resistant strain development, pesticide residue etc. Therefore, the development of resistant grapevine varieties through breeding programs is the most ecofriendly alternative to deal with such pathogen. Thus, marker assisted breeding was initiated at ICAR-National Research Centre for Grapes, Pune to introgress the downy mildew resistance using Thompson Seedless as male parent. The grape genome sequence corresponding to downy mildew QTL ‘Rpv3’, was analyzed and primers were designed for 10 microsatellite regions. Two primers (VVDM2 and VVDM5) showed polymorphism between resistant and susceptible parents, and were validated in 133 F1 progenies of Seyve Villard 12375 × Thompson Seedless. F1 progenies were also screened in-field and in-vitro for their response to downy mildew pathogen. The co-segregation analysis identified significant association of VVDM2 allele with downy mildew resistance and will be useful in early screening of resistant progenies.