INHERITANCE OF BLAST DISEASE RESISTANCE IN THE CROSS HUR 3022 X TETEP OF RICE (Oryza sativa L.)

An experiment was carried out using six generations (P1, P2, F1, F2, B1 and B2) of cross HUR 3022 x Tetep in rice at BHU, Varanasi during year 2017-2018 to know the inheritance pattern of leaf blast disease under artificial inoculation with LB-TN-2 isolate of Magnaporthe oryzae in the field condition.The blast disease resistant cultivar 'Tetep' showed 9.32% disease severity, while high yielding, early maturing susceptible cultivar HUR 3022 showed 43.65% disease severity against M. oryzae.The area under the disease progress curve (AUDPC) of resistance cultivar was observed 127.95 which are significantly less than the susceptible cultivar 605.62.The F1 (HUR 3022 x Tetep) plants were observed to be resistant with an average disease severity and AUDPC are 17.54% and 224.7, respectively.The F2 population was observed to show three distinct phenotypic classes resistant, moderately resistant and susceptible with a ratio of 9:6:1, respectively.Two backcross Populations, B1 and B2 showed different response from each other during evaluation which results in the phenotypic ratio of 1R:2MR:1S in B1 and 1R:0S in B2, respectively.The results showed that blast disease resistance occurs in the cross is due to duplicate cumulative effects or polymeric gene effect of two dominant resistant genes i.e., Pi1 and Pi54.