Moger, NarayanAsha, B.2021-09-182021-09-182016-03https://krishikosh.egranth.ac.in/handle/1/5810175912Late leaf spot (LLS) and rust are the major biotic stresses in groundnut worldwide. An effort was made to map late leaf spot and rust resistance using the recombinant inbred line (RIL) populations derived from TG 26 × GPBD 4 in groundnut. In the present study, 146 RILs were evaluated for LLS and rust resistance and also productivity traits during kharif 2014. The lines differed significantly for the disease resistance and productivity traits. Moderate to high variability, low to high heritability and genetic advance over mean were recorded for LLS, rust and productivity traits. LLS and rust scores showed non-significant positive correlations. Over all, productivity traits were positively correlated with each other. A new linkage map of 1072.64 cM with 20 linkage groups was developed by mapping 17 Arachis hypogaea transposable element (AhTE) markers in addition to the previously mapped SSR markers (210). This linkage map was employed for detecting the genomic regions governing late leaf spot and rust resistance measured at three stages (70, 80 and 90 days after sowing) in 11 seasons (2004-2014). For LLS, two major QTL regions (TE0360-GM2009 and GM2009-GM2079) on AhXV linkage group were detected, which exhibited phenotypic variance explained (PVE) ranging from 49.67-91.78%. For rust, six QTL regions on AhXV showed PVE of 19.07-89.01%. It was found that the two QTL regions (TF0360-GM2009 and GM2009-GM2079) were common for LLS and rust resistance. The markers flanking these QTL were identified, which can be employed for molecular breeding in groundnut for improving resistance to LLS and rust.EnglishThesis