Molecular Diversity and Agronomic Performance of Sesame (Sesamum indicum) Cultivars in Benin: Local Cultivars and Lines Introduced From China.

Abstract

Sesame cultivation was until recently restricted to the northwestern part of Benin. The yield is relatively low, as there are no improved varieties introduced and widely adopted so far. This study aimed to assess the molecular diversity, genetic differentiation, and the agronomic performance of a collection of local cultivars and introduced lines of sesame from China. The agronomic evaluation was conducted across eight environments during the 2020 cropping season using 14 descriptors on 19 accessions, including 6 introduced lines arranged in a randomized complete bloc design. Twelve simple sequence repeat markers were used to assess the molecular diversity. The analysis of variance showed significant variation among accessions for all the traits, except the number of lodges per capsule. Principal component analysis (PCA) followed by hierarchical clustering indicated that the accessions could be classified into three groups. The first group included accessions from China with the local accession SI09, characterized by early flowering and low seed yields (on average 380.13 kg ha^-1). The second group included late flowering accessions and intermediate seed yield (on average 548.68 kg ha^-1). The third group included higher yielding accessions (on average 715.7 kg ha^-1). The PCA identified key traits such as days to 50% emergence, days to 50% flowering, collar diameter, plant height, number of branches, and seed yield as the most discriminative among accessions for agromorphological characterization. The SSR markers were polymorphic, with polymorphic information content values between 0.17 and 0.92. A total of 62 alleles were detected, with each locus exhibiting 2 to 15 alleles. The gene diversity ranged from 0.18 to 0.92, with an average value of 0.55. Cluster analysis based on the unweighted pair group method with arithmetic mean revealed that accessions were grouped in three clusters, with the coefficients of similarity/dissimilarity ranging between 0.60 and 0.92. Most of the Chinese lines were clustered together, except accession Y01. This study provided useful knowledge about local sesame cultivars in Benin and their similarities and differences with the lines introduced from China, therefore contributing to the advancement of the sesame-breeding program in the country.