The first results of molecular breeding for enhancing rust resistance in elite varieties of groundnut (Arachis hypogaea L.)

Groundnut (Arachis hypogaea L.) is a major source of vegetable oil and protein. Rust, caused by Puccinia arachidis, is widespread in most of the tropical countries and severely affects the crop productivity and quality of the produce. Since the trait is governed by recessive genes, use of tightly linked markers will enhance precision in selection of the trait as well as shorten the breeding duration. In this context, using a mapping population derived from the cross TAG 24 × GPBD 4, a major QTL (QTL_rust01) associated with four SSR markers (IPAHM103, GM2079, GM2301, GM1536) contributing upto 82.96% phenotypic variation was identified. After validating these markers in germplasm as well as another mapping population (TG 26 × GPBD 4), molecular breeding has been initiated in three elite groundnut varieties namely ICGV 91114, JL 24 and TAG 24 for enhancing rust resistance. In summary, after deploying GPBD 4 as a donor genotype in marker-assisted backcrossing (MABC), 76 homozygous BC₃F₂ and 158 BC₂F₃ lines have been generated. Initial screening of these lines for rust has identified several promising lines that showed remarkable reduction in disease spread. Multiplication of seeds from the selected lines and field trials will be undertaken in next season to identify the most promising lines with enhanced resistance to rust.