Screening Taro Germplasm against Bacterial Blight Incited by Xanthomonas axonopodis pv. dieffenbachia

Abstract

Sixty-four Taro germplasm accessions from north east India along with two national released varieties were evaluated in natural epiphytotic field condition against bacterial blight incited by Xanthomonas axonopodis pv. dieffenbachia for two consecutive seasons during 2018 and 2019 at an Experimental Farm for Horticultural crops, Assam Agricultural University, Jorhat. The results obtained for the two growing seasons were pooled together. Per cent disease incidence and disease severity ranged from 23.81 (Nepali-2) to 78.57 % (SC-1) and 14.17 (Nepali-2) to 67.50 % (SC-1) respectively. The area under the disease progress curve (AUDPC) which directly corresponds to the bacterial disease infection with time resulting in more susceptibility to the disease ranged from 1612.5 (Sreekiran) to 9812.5 (SC-1). AUDPC was calculated from the per cent disease severity obtained from the first day of disease observation till the last day i.e. from 60 to 240 days after transplanting (DAT). The disease reactions of different germplasm to bacterial blight of colocasia were evaluated based on the disease severity (%) and disease rating scale whereby no cultivars were immune and highly susceptible to the disease. Four accessions viz. Sreekiran, Naga-2, Chandil Pin, Nepali-2 were resistant, twenty-one were moderately resistant, twenty-six were moderately susceptible and fifteen were susceptible. Variety/germplasm resistant to bacterial blight of Taro have not been reported till date. Proper selection of resistant varieties will be useful in breeding programmes and for further crop improvement.