Evaluation of vegetative growth, yield and quality related traits in taro (Colocasia esculenta [L.] Schott)

Taro (Colocasia esculenta [L.] Schott) breeders apply heavy selection pressure on yield during the seminal (F1) and first clonal generations (C1). However, the genetic gain achieved with this practice has never been evaluated and prior accurate assessment of the genetic control of the traits under selection is required. The present study aimed at evaluating broad-sense heritability, between-trait and between-generation correlations, and genetic gain for traits related to vegetative growth, yield, and corm quality. A fully randomized-block trial consisting of 13 full-sib families (1890 genotypes) was set up and measured in F1and C1 generations. ANOVAs were performed with mixed models, considering spatial autocorrelations when necessary. Chi-square tests revealed the stability of the presence or absence of stolons, suckers, and inflorescences between F1 and C1, suggesting strong genetic control for such organs. Highly fitted models resulted in particularly accurate predicted genetic values. Heritability and genetic gain computations assumed unbalanced data and gave rather high values. The number of stolons, the number of suckers, fresh corm weight, and dry matter content were found to be the most heritable traits. Mass and family selection strategies were tested and revealed moderate to high genetic gain for most heritable traits in both generations. Selection indexes such as the vegetative growth index and future breeding strategies are discussed. Results could be of interest for breeding in other aroid crops. (Résumé d'auteur