Phenological, morphological and agronomic characterization of sixteen genotypes of cotton plant (Gossypium hirsutum L.) in rainfed condition in Benin

In Benin, cotton cultivation is rain fed. There is a need to develop varieties adapted to the current diversity of growing conditions caused by climate disruptions. To identify types of varieties that may be used in crossing to adapt varietal offer to climatic disturbances, sixteen genotypes of diverse origins were characterized with a randomized complete block design with four replications. Fifteen agro-morphological variables allowed to describe the genetic variability using descriptive statistics and multivariate analyses. Results showed high genetic variability and a structuration into three groups of genotypes tested. Plant height, length of fruiting branches, height to node ratio, flowering date and opening date of first bolls are the main distinguishing characteristics between groups (p<0.01). The first group consists of compact genotypes with stems, fruiting branches and internodes relatively short. These genotypes were early to flowering and opening bolls. The second group is composed of more vegetative genotypes, with medium size stems with long fruiting branches and long internodes; they are late to flowering and opening bolls. The third group consists of a tall genotype with short fruiting branches and long internodes; it is early to flowering and opening bolls. Compact and early genotypes could be used in crossbreeding to produce varieties adapted to the current climate disruptions.   Key words: Republic of Benin, genetic variability, crop maturity, growth habit, cotton breeding.