Genetic validation of simple sequence repeat markers associated with late leaf spot resistance in groundnut (Arachis hypogaea L.)

Groundnut is often construed as an attractive crop to farmers whereas its pod yield has been greatly challenged by varied forms of stress factors. Among various foliar diseases, late leaf spot (LLS) is considered to be a serious foliar disease resulting in extreme withering of leaflets reducing pod and fodder yield significantly. Genetic markers associated with LLS might differentiate resistant and susceptible progenies. In this investigation, a late leaf spot prone popular groundnut TMV 7 and the resistant groundnut culture ICGV 12625 were crossed and their F2 has been surveyed with 92 simple sequence repeat (SSR) genetic markers for ascertaining the compatible polymorphic markers. The molecular assessment of 92 genetic markers reported the 13 genetic markers to exhibit genetic polymorphism between parent groundnut TMV7 and ICGV12625. The polymorphic genetic markers can be utilised for bulk segregant analysis (BSA) and as such 6 molecular markers were construed to differentiate the categories of resistance in bulks and individual plants towards late leaf spot disease. Validation of single marker had shown that IPAHM 524, TC7H11, Ah3TC23H10, Ah3TC24B05, Ah3TC28B01 and GM 2079 were linked with late leaf spot severity score in bulks. The observable trait variation elucidated by these markers over a range of 44 and 59 %. The second filial crosses (F2) crosses had given the 3:1 pattern of susceptible and resistant progenies in the chi-square test pointing the predominant role of monogenic recessive gene control for LLS resistance. The markers ascertained through bulk segregant analysis were further substantiated with single marker analysis. Further, the genetic markers IPAHM 524198, TC7H11148 and Ah3TC23H10172 could be able to differentiate the resistant and susceptible individual plants among the selected genetic stocks exhibiting wider genetic background with the assistance of marker-assisted crop improvement.