ASHS 2025 Conference

Sweet potato (SP) is a staple in many countries, primarily used for human consumption, but also showing potential for animal feed, ethanol production, ornamental use, and industrial applications. SP is mistakenly considered tolerant to drought, but water shortage can significantly compromise the yield and quality of this crop. It is frequently cropped in drought-prone environments, characterized by sandy soil and high temperatures. Identifying drought-tolerant genotypes is essential for the development of future-ready cultivars. This study aimed to evaluate physiological, biochemical, and morphological responses of sweet potato genotypes to water deficit conditions. A completely randomized experimental design was adopted in a 2 x 20 factorial scheme with four replicates. The first factor consisted of two water regimes, 20 and 100% of pot capacity. The second factor included 20 genotypes. Plants were grown in 12L-pots filled with a 2:1 soil-to-sand mixture. All plants were irrigated at full pot capacity for five weeks to ensure establishment. Subsequently, water regimes were imposed employing time-domain reflectometry (TDR) sensors, and evaluations were conducted four weeks later. Parameters assessed included chlorophyll fluorescence, biomass, water potential, gas exchange, biochemical parameters, and secondary metabolites. Genotypes responded differently to water regimes, revealing considerable genetic variability for drought tolerance. Water deficit negatively affected the performance of several genotypes, particularly in relation to the variation of minimum fluorescence (Fv/F0), leaf water potential, and electron transport rate. Correlation analysis showed strong associations among traits of stressed plants. There was a high positive correlation between leaf water potential and fresh mass of the aerial part, as well as the photosynthetic rate with the chlorophyll fluorescence parameters Fm and Fv/F0. Genotypes ‘Luiza’, ‘Canadense’, ‘CIP-420717', ‘Maria Isabel’, and ‘CIP-440186' exhibited superior performance under drought conditions and are promising candidates for breeding programs targeting drought tolerance.