Marker assisted backcross breeding for submergence tolerance in rice variety Rajendra Sweta

Abstract

Submergence stress regularly affects rice crop in major parts of eastern India comprising Odisha, West Bengal, Bihar, Assam, Chhattisgarh and eastern Uttar Pradesh. Out of 42 biotic and abiotic stresses that prevail in rainfed lowland rice areas of eastern India, submergence stress is the third most important limitation to rice production. A major QTL mapped on chromosome 9, designated as sub1, has provided the scope to apply marker assisted backcrossing (MABC) to develop submergence tolerant varieties suitable to be grown in these regions. Developing rice cultivars with tolerance of submergence and with agronomic and quality traits acceptable to farmers is a feasible approach to address this problem. In the present study, BC2F1 generation was developed between a submergence tolerant donor, Swarna-Sub1and the widely grown recurrent parent, Rajendra Sweta. A parental polymorphism survey between these two parents revealed 46 polymorphic SSR loci covering all the chromosomes of rice genome. Foreground selection was done in each generation for the confirmation of Sub1 QTL. Molecular markers that were tightly linked to Sub1, flanking Sub1 and unlinked to Sub1 were used to apply foreground, recombinant and background selection, respectively, in BC2F1 generation. Out of 91 plants, 50 plants were found positive in foreground selection using Indel primer Sub1bc2. newline