Simple Sequence Repeat Polymorphisms in Nigerian Sesame Cultivars and its Relationship with Morpho-Agronomic Traits

Abstract

Sesame (Sesamum indicum L.) is an important oilseed crop of global importance. The genetic diversity of 30 Nigerian sesame cultivars was characterized using simple sequence repeat (SSR) markers, and the molecular polymorphisms were related to the divergence in morpho-agronomic traits. The cultivars varied significantly in shattering characteristics, days to germination (4–7 days), plant height (85–183 cm), flowering time (60–125 days), number of flowers/axil (1–2), maturity period (89–130 days), and seed size (6.2–8.0 mm). Significant correlations were observed among these morpho-agronomic traits, with the strongest correlation being between days to germination and shattering characteristics (r = 0.937, p < 0.0001). The potential utility of the SSR marker technology in sesame genome analysis was assessed based on the screening of 10 sesame SSR primer pairs that were highly polymorphic. Three to six alleles were observed per SSR locus, with an average of 4.6 alleles in the sesame genome and fragment size ranging from 150 to 307 bp. High genetic variability was found among the accessions, with the repeat motifs (TC12–TC25) from two selected highly informative primer pairs clearly differentiating the 30 cultivars into eight groups. The observed diversity at the molecular level closely reflected the wide variation in phenotypic traits and can serve as a useful tool for unlocking the genetic diversity in the Nigerian sesame cultivars for plant breeding purposes.