Assessment of Novel Genetic Diversity Induced by Mutagenesis and Estimation of Genetic Parameters in Sesame M₄ Mutant Lines

Abstract

Sesame (Sesamum indicum L.) is an ancient oilseed, aromatic, and medicinal crop widely used for its high-quality oil and seeds. The available genetic diversity in Morocco is too limited; thus, a mutagenesis breeding program was adopted. This study was carried out to evaluate the novel variability induced and observed in 11 M4 mutant lines and to estimate some valuable genetic parameters. The experiment was conducted in two different environments using a randomized complete block design with three replications. Phenological, morphological, and agronomic traits were recorded. To estimate the effect of genotype, environment, and their interaction, ANOVA and planned contrast analyses were performed. To examine relatedness among genotypes, cluster analysis was performed. Significant differences among mutants and between parent cultivars and their respective mutant lines were observed. Genetic parameters such as genotypic (GCV) and phenotypic (PCV) coefficients of variation, broad-sense heritability (H2 b.s), genetic advance (GA), and genetic advance over the mean (GAM) were high in most traits. Highly productive mutants, ‘US2-1’ and ‘US1-2’, were observed, exhibiting the highest number of capsules per plant and seed yield ever reported. Additionally, there are other promising mutants with early flowering, early maturity, and a reduced height of the first capsule. This suggests that mutagenesis can be successfully applied to develop high-yielding sesame varieties along with other improved phenological and agromorphological traits. All these mutant lines can be used as promising germplasm to develop competitive sesame cultivars to meet the increasing demand for sesame oil and seeds in the actual context of climate change.

Keywords

• sesame
• mutagenesis
• agronomic trait
• heritability
• genetic advance
• early flowering