M4 generation of moringa (Moringa oleifera Lam.) mutants revealing genetic diversity for leaf traits based on SSR markers

This study was conducted to develop a variety suitable for high leaf production in moringa. Initially, seeds of PKM 1 variety of moringa were treated with gamma irradiation of 100 Gy (Gray), 200 Gy and 300 Gy at Bhabha Atomic Research Centre (BARC), Mumbai and raised as M1 generation. The best-performing mutants were selected and forwarded to further generations (M1 to M4) based on leaf-related characters. A total of 10 Indian drumsticks (Moringa oleifera Lam.) mutants (derived from 200 Gy of gamma irradiation) from M4 generation with PKM 1 variety were evaluated for morphological and molecular diversity. To evaluate morphological diversity, 4 features (leaf length, leaf breadth, fresh weight and dry weight) were studied under field conditions. Ten sets of markers for simple sequence repeats (SSR), i.e. GenicSSR1081, SSR25987, SSR2927, GenicSSR859, GenicSSR796, SSR6561, GenicSSR890, GenicSSR1204, GenicSSR983 and GenicSSR778; that generated distinct and repeatable bands; were chosen for analyzing molecular diversity. A total of 24 bands were amplified, of which 17 were polymorphic. With an average of 0.391, the polymorphic information content (PIC) values for SSR markers varied from 0.124 for marker SSR2927 to 0.719 for marker GenicSSR778. Based on the cluster analysis with SSR markers, the mutants are divided into 2 groups. The variety PKM 1 was separated by a group whereas; all the other mutants fell into a single group indicating the diversity of mutants from the control. The diverse mutants (15-1-09-70 and 15-1-09-53) based on both morphological and molecular observations were selected and suggested for evaluation through subsequent generations that have the potential to be released as a variety for high leaf production. By increasing the production of highly nutritious moringa leaf, self-sufficiency and nutritional security can be obtained as well as it could benefit the lifestyle improvement of farmers through export to countries where the crop demand is high.