Identification of Sweet Potato Accessions Tolerant to Water Deficit

Abstract

Water deficit is a major constraint to sweet potato (Ipomoea batatas L.) production, particularly in tropical regions characterized by high climatic variability. This study evaluated the agronomic response of 40 sweet potato accessions under two water regimes (irrigated and water deficit) to identify drought-tolerant genotypes. The experiment was conducted at the research station of the Centre National de Recherche Agronomique (CNRA) in Bouaké, characterized by a humid tropical climate, an average temperature of approximately 28 °C, and gravelly ferralitic soils. A split-plot experimental design was adopted to evaluate the main agronomic traits, while drought tolerance indices were determined and complemented by multivariate analyses. Water deficit resulted in a reduction of storage root weight and total yield by more than 40%, whereas emergence and the percentage of productive plants were less affected (<20%). Marked variability was observed among accessions. Accession CNRA PD19/000030 stood out with a yield reduction of less than 20% and tolerance indices above 70%, while several accessions experienced nearly complete yield losses under water stress conditions. Multivariate analysis clearly discriminated tolerant genotypes from sensitive ones. These findings reveal substantial genetic variability in drought response and identify promising accessions for breeding programs aimed at enhancing sweet potato resilience to increasing water scarcity.