Abstract

Introduction
Lathyrus (Lathyrus sativus L.), an important pulse crop, is valued for its high protein content and resilience to abiotic stresses. However, its cultivation is limited due to the presence of the neurotoxin β-ODAP, which causes neurolathyrism. Mutation breeding offers a viable approach to develop low-toxin, high-yielding varieties. This study aimed to evaluate genetic variability, estimate heritability, and identify superior mutants in M~4~ progenies of Lathyrus cv. NLK-73 for yield and related traits with reduced β-ODAP content.

Methods
Twenty-nine mutant progenies derived from gamma-ray-irradiated NLK-73 seeds, along with checks (NLK-73 and Ratan), were evaluated in a Randomized Block Design with three replications. The data recorded included days to first flowering, days to maturity, plant height, number of branches/plant, pods/plant, 100-seed weight, seed yield/plant, and β-ODAP content. Genetic parameters such as genotypic and phenotypic variance, heritability, and genetic advance were estimated.

Results
Analysis of variance revealed significant genetic variability among mutants for all traits. High genotypic coefficients of variation (GCVs) and heritability were observed for branches/plant (42.06%, 87.46%), pods/plant (20.86%, 48.79%), and seed yield/plant (16.83%, 41.40%). Moderate to high genetic advance was recorded for these traits, indicating additive gene action. Ten superior mutants (e.g., NLM-12, NLM-20, and NLM-23) were identified, exhibiting high yield (>23 g/plant), increased pods/plant (>49), and low β-ODAP content (<0.20%).

Conclusions
The study demonstrated the potential of mutation breeding to enhance yield and reduce β-ODAP in Lathyrus. Selected mutants with high heritability and genetic advance can be advanced for further trials, contributing to safer and more productive Lathyrus cultivars.