Phenotypic Screening of Rice Tungro Disease Resistant Transgenic ASD 16 Rice Lines Obtained through Marker Assisted Backcross Breeding

Rice tungro is a viral disease seriously affecting rice production in South and South East Asia and is caused by the joint infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). In order to diversify the transgenic resistance for tungro from transformed Pusa Basmati-1 into superior but highly susceptible variety ASD 16, marker assisted backcross breeding was followed. To confirm the RTBV résistance obtained through marker assisted backcross breeding, phenotypic screening of the selected homozygous plants of transformed ASD16 was done using viruliferous GLH. The plant height and chlorophyll content of these selected lines, wild resistant varieties (Utri Merah, Utri Rajappan, Pankhari 203 and Vikramarya), susceptible variety TN 1 and normal ASD 16 under infected as well as control conditions were measured. The selected homozygous plants of the transformed ASD 16 showed reduced tungro symptoms than the normal ASD 16 and TN 1 thus confirming the effeciency of the transgene imparting resistance against Rice Tungro Disease (RTD).