Assessment of Groundnut Germplasm Lines for Foliar Fungal Diseases and Population Structure Analysis using Gene Based SSR Markers

Introduction: Peanut (Arachis hypogaea L.) is an exceptional cash crop having versatile applications of each plant part. Rust and late leaf spot (LLS) are two main foliar fungal diseases of groundnut and can cause yield damage up to 70%. Employment of fungicide is expensive approach and it is not environment-friendly also, consequently breeding new cultivars with genetic resistance is sustainable, eco-friendly and cost-effective method.

Aim: The present investigation aimed to screen groundnut germplasm lines employing allele specific molecular markers against foliar fungal diseases (LLS and rust).

Study Material: The present investigation contained 30 uncharacterized germplasm lines along with 4 check varieties of peanut. A set of 4 gene based SSR molecular markers were designated for screening of groundnut germplasm lines against foliar fungal diseases i.e., LLS and rust.

Results: For polymorphic SSR markers, a total of 14 alleles were identified, with an average of 3.5 alleles per locus. With an average of 0.47, the gene diversity and Polymorphic Information Content (PIC) values ranged between 0.3972-0.5778. In a UPGMA tree based on SSRs, the genetic links between peanut genotypes are shown. Four major demographic groups were formed using principle coordinate analysis (PCA) depending on origin. The population structure of the 34 genotypes was assessed employing STRUCTURE v2.3.3 software based on SSR markers. The optimum K value was determined by employing Structure Harvester, where the highest peak was observed at delta K = 2. The number of sub populations (K) was identified based on maximum likelihood and delta K (dK) values, with two core and pure groups and an admixture group. Present investigation identified four germplasm lines viz., AH8054, CS21181, CS708 and Akola White that may be used as foliar disease resistant cultivar for groundnut hybridization and improvement programme.