DAMODAR RAJU, ChBASAVARAJ, P S2020-11-032020-11-032020D10,498https://krishikosh.egranth.ac.in/handle/1/5810154211Rice is the major food crop of India and being the primary center of origin, it possesses huge diversity of both wild and cultivated species. The present study was undertaken to study the genetic and molecular analysis of advanced backcross population from Samba Mahsuri/Oryza rufipogon for yield enhancing traits and blast resistance. A popular cultivar Samba Mahsuri and O.rufipogon Acc. VN90-1032 was used to develop 192 (BC2F3) introgression lines (ILs) following advance backcross and consecutive selfing strategy. The analysis of variance revealed significant differences among all the traits over the both seasons indicating the presence of considerable genetic variability among the experimental material under study. Studies on variability revealed that phenotypic and genotypic coefficients of variation were high for number of productive tillers/plant, 1000 seed weight, number of spikelets per panicle and grain yield/plant indicating the existence of wider genetic variability for these traits among the ILs. High heritability coupled with high genetic advance was recorded for traits such as plant height, number of tillers/plant, number of productive tillers/plant, panicle length, number of spikelets/panicle, spikelet fertility, 1000 seed weight and grain yield/plant indicating the preponderance of high additive variance. A total of 192 introgressed lines were screened for blast resistance under Uniform Blast Nursery (UBN) at ICAR-IIRR, Hyderabad during 2018, The study revealed that out of 192 ILs screened for blast disease, 28 lines recorded resistance reaction (<3 score) and 164 lines recorded susceptible reaction (>4-8) and Samba Mahsuri were found highly susceptible with a score of 9. The 26 (2 lines not germinated) out of 28 blast resistance ILs identified were further screened during Kharif 2019 and 25 lines recorded resistance reaction score <3, and IL-3 showed moderately resistant reaction, indicating these blast resistance lines carry resistance source from wild rice parent. The 26 blast resistance lines were further genotyped with eight major blast resistant genes viz., Pi1, Pizt, Pib, Pi9, Pi54, Pi38, Pitp and Pi20 to ascertain the gene(s) conferring resistance for blast resistance. Among the 26 Introgression lines, IL-136 showed positive for six blast resistance genes (Pib, Pi9, Pi54, Pi38, Pitp and Pi20), IL-3 (Pib, Pi54, Pi38, Pitp and Pi20) and IL-140 (Pib, Pi9, Pi54, Pi38, and Pitp) positive for five genes, five ILs viz., IL-134, IL-4, IL-29, IL-133 and IL135 showed positive to four genes. Based on performance of introgression lines for yield enhancing traits and blast resistance genes (Pi1, Pizt, Pib, Pi9, Pi54, Pi38, Pitp and Pi20),based on yield and yield attributing traits and resistance to blast seven introgression lines (IL-27, IL-28, IL-29, IL-72, IL-139, IL-158 and IL-171) were identified as promising and further used for estimating the recovery of recurrent parent using 117 polymorphic SSR markers distributed across genome. Of seven ILs, IL-27 recorded maximum recovery (92.3 %) of recurrent parent genome whereas IL-158 recorded lowest 54.0 %. These promising lines can be used as donor in breeding programme.EnglishThesis