Development and characterization of ethyl methane sulfonate (EMS) induced mutant population of grass pea with yield, quality and forage traits
Grass pea (Lathyrus sativus L.) is an important protein-rich annual legume crop that can survive harsh environment conditions. Genetic improvement of grass pea is highly important for expanding its production, and mutation breeding can be a valuable tool in creating additional genetic variability. In the present study, we treated totally 3000 seeds of widely cultivated grass pea cultivar, Gürbüz-2001, with two different concentrations (0.5% and 1%) of mutagen EMS for 4 hours. The germination rates were calculated as 71.6% (1074 plants) and 42.4% (636 plants) for 0.5% and 1% EMS concentrations in M1 generation, respectively. We identified several mutant phenotypes such as seedling growth defects, abnormal branching, chlorophyll mutants, absence of flowering, and sterility in M1 and M2 populations. A total of 40 mutant plants which were superior than control variety in terms of vegetative components from M2 population were selected for agronomic, quality and forage traits analysis. Plant height of mutant lines ranged from 48 (GMP29) to 164 cm (GMP4), with an average value of 109.7 cm. One of the most interesting features of some mutant lines was the significant increase in 1000-seed weight over the control value, contributing to higher yield. The seed yield ranged from 7.19 to 87.18 g, and the lines GPM6 and GMP11 showed superior values compared to the control (13.6 g), indicating the positive effect of mutation in obtaining desired traits. There were promising mutants that showed higher levels of protein content among mutated lines. The β-ODAP (β-N-Oxalyl-l-α,β-diaminopropionic acid) content of grass pea seeds ranged from 0.139% to 7.39% in selected M2 population, while the control cultivar was 0.523%. GPM6 and GPM11 were important for forage breeding with their high crude protein content, low ADF (acid detergent fiber) and NDF (neutral detergent fiber) ratios, as well as high seed and biological yield. The beneficial traits of these mutants obtained in this study should be followed to integrate as genetic resources for use in grass pea improvement programs.