Executive Summary : | Epidemic outbreak of brown spot disease of rice caused by Bipolaris oryzae in 1942 in Bengal Province of India caused severe shortage of food grain leading to Great Bengal Famine. This disease presently prevalent in upland rice and direct seeded rice cultivation areas and known to cause yield losses up to 52%. Production Oriented Survey by ICAR-IIRR reported brown spot as threatening disease in the states of MP, UP, Bihar, Chhattisgarh, Odisha, Assam, Jharkhand, Punjab, Karnataka, AP, Telangana and West Bengal. Development of brown spot resistant cultivar is economically feasible and environmentally viable approach for management of disease. At ICAR-IIRR, large number of rice germplasm screening for brown spot disease under artificial inoculation revealed susceptibility of most of the cultivars. The reported donors for brown spot disease resistance namely CH45, IR-64, Tadukan, Rasi, Phalguna also showed moderate susceptible reaction. Consequently, there are no durable resistance donors presently available to further utilise in the breeding program in India. It is imperative to identify the durable resistance genotypes and molecular markers associated with the resistance in order to utilised in marker assisted breeding for development of brown spot resistance cultivars. Wild species of rice known to harbour valuable genetic variations of biotic stress resistance. Screening of Oryza rufipogon derived 255 introgression lines (BC1F8) at brown spot screening nursery was undertaken for two seasons. The study identified CGIL8, the Oryza rufipogon derived introgression line as promising resistance to brown spot disease. Hence, the CGIL8 was crossed to Samba Mahsuri (highly susceptible) and developed 192 lines of F2 population. The F2 (CGIL8/Samba Mahsuri) population will be utilized for mapping genomic regions associated with brown spot resistance. The study will be identifying the molecular markers linked to brown spot resistance gene derived from O. rufipogon and this further enables us in development of durable brown spot resistance cultivars. The pathogen Bipolaris oryzae reproduces both sexually and asexually facilitating the evolution rapid variants. However, in India, no systematic study on pathogen variability of Bipolaris oryzae is carried out. Patho-molecular characterization of brown B. oryzae from diverse rice growing areas of India, helps to understand the pathogen population structure, to identify virulent strains; thus helps in brown spot resistance breeding programme. Therefore, it is proposed to undertake the molecular characterization of Bipolaris oryzae from major rice growing ecologies of India. |
Co-PI: | Dr. C. Gireesh, ICAR - Indian Institute Of Rice Research, Hyderabad, Telangana-500030, Dr. Satyaswara Jasudasu Gompa, ICAR - Indian Institute Of Rice Research, Hyderabad, Telangana-500030, Dr. V Prakasam, ICAR - Indian Institute Of Rice Research, Hyderabad, Telangana-500030 |