Mutagenesis for Qualitative and Quantitative Traits in Papaya (Carica Papaya L.)

Abstract

The study, "Mutagenesis for Qualitative and Quantitative Traits in Papaya (Carica papaya L.)," aimed to investigate the effects of gamma irradiation and EMS on papaya seed germination, seedling growth, vegetative characteristics, and yield and fruit quality of the papaya cultivar under varying doses of gamma irradiation and EMS. The experiment was carried out during 2022-23 and 2023-24 at the Horticultural Research Centre of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut-2501100 (U.P.), India. The experiment was performed on two papaya cv. Coorg honey dew and Arka surya by exposing the healthy and dry seeds treated with gamma rays, viz., 5, 10, and 15 GR, EMS doses of 0.25, 0.50, and 0.75%, and both combinations of gamma rays + EMS at 5 GR + 0.25 EMS, 10 GR + 0.50 EMS, and 15 GR + 0.75 EMS doses. The observations recorded during research work, viz., for growth traits, Days taken for germination, Days taken to first flowering, Plant height at first flowering, Plant height at full maturity, Number of leaves at first flowering, Time from first flowering to harvesting, Days taken to fruit set, Stem girth (cm), petiole length (cm), for yield traits, Number of fruit per plant, Fruit yield per plant (kg/plant), for physical traits, Fruit weight (cm), Fruit length (cm), Fruit girth (cm), Pulp thickness (cm), Breadth of central cavity (cm), Fruit firmness, Number of seeds per fruit, for chemical traits, Total soluble solid. Seeds treated with 10 GR doses of gamma rays, 0.50% ethyl methane sulphonate, and both gamma rays and EMS (10 GR + 0.50% EMS) had better performance for most traits except Plant height at first flowering, number of leaves at first flowering, petiole length (cm), and number of seeds per fruit 5 GR, 0.25% EMS, and 5 GR + 0.25% had better performance for the traits, while 15 GR, 0.75%, and 15 GR + 0.75% EMS for the trait breadth of the central cavity. However, 5GR, 0.25% EMS, and 5GR+0.25% EMS and 15GR, 0.75%, and 15GR+0.75% EMS had lower performance on most traits. Based on the findings of the current study, it can be concluded that gamma irradiation at a dosage of 10 GR, 0.50% EMS, and 10 GR+0.50% EMS were the most effective doses for improving most of vegetative growth, yield, and quality characteristics. Conversely, dosages, such as 5GR, 15GR, 0.25% EMS, 0.75% EMS, 5GR+0.25% EMS, and 15GR+0.75 EMS, had a lesser effect on vegetative growth, yield, and quality traits. Therefore, these specific dosages and concentrations of mutagens may be utilized to induce genetic variability, facilitating effective selection for improved yield and quality characteristics in papaya.