Sweet potato is generally known as drought tolerant crop, however cannot withstand drought during initial planting and during initial growth stages including development and tuber intitiation and thus there is need to identify appropriate genotypes adapted to drought conditions. The aim of this study was to evaluate different sweetpotato genotypes subjected to drought stress to identify the most drought tolerant genotypes and select the best index for investigating sweetpotato genotypes under stress and non-stress conditions. Twenty four sweetpotato genotypes were screened for drought tolerance under the screen house. The trial was assessed using a randomised complete block design with three replicates. The analysis of variance showed significant differences in genotypes under drought stress condition. Five different drought tolerant indices including mean product, geometric mean product, stress tolerance index, tolerance and stress susceptibility index were used to identify high yielding genotypes under both conditions. The stress susceptible index(SSI) is considered as suitable indices for sweetpotato where stress is severe while mean product (MP),geometric mean product (GMP), Stress tolerance index (STI), and Tolerance (TOL) were considered the potential indices for selecting high yielding sweetpotato genotypes under both conditions using harvest index yield component. Correlation analysis between harvest index yield under stress and non-stress condition showed positive correlation amongst GMP, MP and STI and showed that the most appropriate indices to identify drought tolerant genotypes were GMP, MP and STI.Principal component analysis through biplot was used to explain the variation between the harvest index yield component and the drought indices. The genotypes 1,2,3 and 5,were classed as drought tolerant and in group A while genotypes 4,8, and 7 were considered as group B and can produced high yield only under high soil moisture condition.
