Grass pea (Lathyrus sativus L.) development of forward lines by applying EMS mutagen

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 seeds of widely cultivated grass pea cultivar, Gürbüz-2001, with two different concentrations (0.5% and 1%) of mutagen ethyl methane sulfonate (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. However, the seeds of a total of 776 plants capable of producing seeds were harvested separately (M2) and replanted the following year. In the observations, several mutant phenotypes were identified, including seedling growth defects, abnormal branching, chlorophyll mutants, absence of flowering and sterility in both 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, while the average value was 75 cm for the control. 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 acid detergent fiber (ADF) and neutral detergent fiber (NDF) 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.