Introgression of Transgenic Resistance for Rice Tungro Disease into Mega variety, ASD 16 of Tamil Nadu through Marker Assisted Backcross Breeding

Abstract

Rice Tungro is a viral disease caused by the joint infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). In order to obtain transgenic resistance against RTBV, indica rice cultivar, Pusa Basmati-1 (PB-1) was transformed to express the coat protein gene of an Indian isolate of RTBV. The transformed PB-1 showed a concomitant reduction of tungro symptoms. The present study was attempted to diversify this transgenic resistance against tungro disease from PB-1 into superior but highly susceptible variety, ASD 16 by following marker assisted backcross breeding. ASD 16, was crossed with transgenic PB1 and the F1 plants were repeatedly backcrossed with the recurrent parent ASD 16 to obtain BC3F1 population. The transgenic plants that contained the RTBV resistant transgene were identified in BC3F1 and BC3F2 population by PCR analysis using functional marker associated with that gene. These foreground selected plants were subjected to background analysis and it revealed that there was 100 per cent recovery of the recurrent parent genome in BC3F2 plants.