ABSTRACT
The present investigation was focussed on regeneration, evaluation and screening of somaclones for yellow leaf disease(YLD) resistance using in vitro mutagenesis from a popular susceptible sugarcane variety Co86032 using four chemicalmutagens at three levels of concentration (sodium azide (SA) at 0.5 mg L-1, 1.0 mg L-1, 1.5 mg L-1; sodium nitrite (SN)at 3 mg L-1, 5 mg L-1, 7 mg L-1; ethyl methane sulphonate (EMS) at 0.6 lM L-1, 0.8 lM L-1, 1.0 lM L-1 and 2,4 D at 4mg L-1, 5 mg L-1, 6 mg L-1). A total of 1138 tissue culture seedlings obtained were evaluated for virus resistance both innatural field conditions and in controlled greenhouse condition after aphid vector transmission and presence or absence ofvirus was observed by visual screening and reverse transcription-polymerase chain reaction method. Four out of 207asymptomatic plants (16T22, 16T23, 16T29 and 16T31) were devoid of virus coat protein band and were considered to beYLD resistant. The obtained resistance somaclones showed inferior yield traits so they have to be exploited as parents inhybridization programmes with commercial varieties to impart YLD resistance ultimately yielding agronomically superiorYLD-resistant varieties in sugarcane.