Improving Taro ( <i>Colocasia esculenta</i> [L.] Schott.) Genotypes for Resistance to Taro Leaf Blight Disease in Ghana

This study explored the variation in taro leaf blight disease (TLBD) in Colocasia esculenta by examining five parent genotypes and their corresponding 20 single‐cross hybrids. A full diallel crossing design was employed and assessed under both naturally occurring field infections and controlled artificial inoculations. The study focused on the evaluation of general and specific combining abilities, estimating heterosis and calculating heritability values. The parents and hybrids were tested for TLBD resistance across three agroecological zones in Ghana using a randomized complete block design (RCBD) with three replications. 2‐week‐old, fully expanded leaves harvested from each genotype at each location were inoculated with Phytophthora colocasiae using the leaf disc method. At 8 weeks after planting (WAP), the research fields were also assessed for TLBD incidence and disease severity index (DSI). There were highly significant general combining ability (GCA) and specific combining ability (SCA) effects for lesion area and disease severity, indicating both additive and nonadditive gene actions, while disease incidence was influenced mainly by nonadditive effects. Most of the progenies exhibited significant ( p &lt; 0.01) negative mid‐parent heterosis (MPH) and better‐parent (BP) heterosis for the traits. High broad‐sense and medium narrow‐sense heritability were recorded across traits. Parents 3, 4, and 5, which recorded good breeding value for TLBD resistance, are recommended to be included in taro improvement programs to develop resistant varieties. Hybrids 10, 11, and 14, which exhibited strong TLBD resistance, can be released to farmers for cultivation.