Dr. PRASHANTHI S. K.DNYANESHWAR B. DESHMUKH2018-04-042018-04-042015-05http://krishikosh.egranth.ac.in/handle/1/5810042911Rice blast (Magnaporthe oryzae Couch-Kohn) is one of the most serious, widespread and destructive diseases of rice. Thirty four M. oryzae isolates were analysed for morphological and molecular diversity. Transposable element Pot2 based fingerprint profile grouped 34 isolates into cluster-1 and 2 which shared low similarity value of 0.03. Molecular diversity was noticed in leaf and neck blast pathogen populations collected within location and varieties. Near isogenic lines (NILs) of BPT5204 developed by marker assisted backcross breeding (MABB) were characterized for blast resistance genes viz., Pi2, Pi5 and recurrent parent alleles by using molecular markers. Out of 74 RM markers screened for back ground analysis, 42 markers were polymorphic between IRBLz5-M (Pi5 donor) and BPT5204 and forty markers were polymorphic between ‘C101A51’ (Pi2 donor) and BPT5204. In NILs with Pi2 gene recurrent parent genome (RPG%) varied from 66.66 (DHA-5) to 90.27% (DHA-17). In NILs with Pi5 gene RPG% ranged from Pi5 gene RPG ranged from 71.95% (DHB-29 and DHB-32) to 91.46% (DHB-1 and DHB-19). NILs were field evaluated for blast resistance, yield and yield related traits at different locations. In screening for blast resistance under multi-locations, NILs showed resistant (1 - 3 grade) to moderately resistant (4-5 grade) reaction. Positive correlation was observed for yield per hectare with thousand grain weight, number of tillers per plant, productive tillers per plant, grain yield per plant and number of grains per panicle traits in NILs. Grain quality tests viz., kernel length/ kernel breadth ratio, amylose content, gelatinization temperature, grain chalkiness and alkali spreading value were performed. Combined analysis of morpho-agronomic performance and grain quality parameters showed that NILs with Pi2 gene, DHA-1, 2, 10, 16, 17 and 20 and NILs with Pi5 gene, DHB-1, 9, 18, 21, 28 and 31 were found to be on par with BPT5204.ennullThesis