MORPHOLOGICAL CHARACTERIZATION OF SESAME GERMPLASM IN THE STATE OF GUERRERO, MEXICO

Abstract

Despite the high demand for sesame (Sesamum indicum L.), both for domestic consumption and for export, new varieties have not been released for more than two decades because during that time no genetic improvement has been carried out in Mexico. In order to explore the phenotypic diversity and performance of sesame germplasm available in banks, some improved varieties and other materials introduced in two sites comprising four environments in the state of Guerrero, Mexico 50 genotypes were evaluated in the Spring-Summer 2021 and 2022, based on 24 morphological descriptors, being 11 quantitative and 13 qualitative. Principal component, correspondence and cluster analyses were carried out. The quantitative variables that showed greater relevance to distinguish genotypes were length and width of the leaf blade, days for the beginning of flowering, plant height, number of nodes to the first flower and days for the beginning of capsule maturity, while the qualitative variables of greatest importance were degree of lobulation of the leaf blade, length/width ratio of the leaf blade, number of branches per plant, development of extra floral nectarium and number of flowers per leaf axil. Cluster analysis led to the formation of two groups based on characteristics of similarity within the groups and dissimilarity between groups. In similarity, 39 genotypes (78 %) were clustered in Group I and 11 genotypes (22 %) in Group II, while in dissimilarity, Group I presented 0.25 phenotypic distance and 0.38 for Group II. Although there is a high percentage of phenotypic similarity in the germplasm evaluated, there are at least two genetic groups of variability that can provide new usable diversity for sesame genetic improvement programs through crossing and recombination.