The effect of drought and cultivar on growth parameters, yieldand yield components of potato

Four potato cultivars (Solanum tuberosum L.) differing in their precocity and contrasted for their drought tolerance were investigated in the field and in the greenhouse ( 2 cultivars). They were subjected to two water treatments, well-irrigated and droughted. Our objective was to examine which shoot and leaf characters were related to the decrease in tuber yield. Drought reduced tuber yields by 11% in 53%. Drought stress highly reduced the dry mass of leaves in all cases. Tuber number was reduced only in early cultivars whereas in the later cultivars, leaf area index and leaf area duration were more affected than in the early cultivars. The cultivar which maintained its tuber growth rate better under drought during the first three weeks of tuber bulking also maintained its yield better. No clear common reaction of early versus later varieties to drought was found.