Incidence of Anthracnose in Indigenous Germplasm of Dioscorea alata L.

The incidence of anthracnose in indigenous germplasm collection of Dioscorea alta L. from different agro-ecological regions of peninsular India were scored on a 0–9 subjective scale under the field epiphytotic condition and percentage infection index was calculated. The study indicated that different morphotypes of D. alata varyingly responded tothisdisease. Analysis of correlation betweendisease incidence, number of stomata, stomatal size index and average yield/plant showed negative correlation between disease incidence and number of stomata, between number of stomata and stomatal size index and between disease incidence and average yield/plant indicating reduction in yield with the higher incidence of anthracnose. Frequency class distribution of intensity of disease incidence showed a slightly abnormal curve indicating a discontinuous and fragmented genetic variability exisitng in the collection with respect to resistance/susceptibility to anthracnose incidence.