Induced Mutagenesis for Improvement of Garden Pea

Abstract

Induced mutation has become an effective tool to improve a crop through creation of variability. Seeds of Garden pea (Pisum sativum L.), cvs. Arkel and Azad P-1, were exposed to mutagens in 2004 to 2006. The M1 generation was produced from these mutagen-treated seeds. A wide range of chlorophyll and viable morphological mutations were obtained in the M2 generations (subsequent generation derived from seed harvested in M1). Additional seeds of the cultivars were treated with doses of 60Co gamma rays and ethyl methane sulphonate (EMS) from 2004 to 2006 to isolate more desirable mutants. Chlorophyll mutation rate in the M2 generations increased as gamma irradiation dose and concentration of EMS increased. Frequency of viable mutants was, in general, higher in treatments with EMS than with gamma rays, with the exception of gamma irradiated ‘Azad P-1’ in 2006. The frequency of total mutants increased with increasing dose of mutagens at similar rates in cultivars over years. Among chlorophyll mutants, frequency of the xantha type (pale yellow colored seedlings) was higher followed by chlorina (yellowing of leaf) and albina type (completely devoid of chlorophyll) mutants. Treatment with 0.3% EMS was, in general, more effective in inducing desirable mutations at the highest frequency, and ‘Arkel’ had more positive mutations than ‘Azad P-1’. The desirable mutants of long and dark green pods, three or more flowers or pods on a peduncle, profuse branching and pod bearing, short internodes, dark green pods, and male sterility were isolated from different treatments over years. Lethality or biological injury, manifested as reduced germination, increased with increasing dose of gamma rays and EMS. Mutagenic effectiveness and efficiency generally increased with increasing EMS dose. Mutation breeding can play a role in pea improvement to induce useful variability of desirable traits to develop improved genotypes.