Division of Vegetable Crops, Indian Agricultural Research Institute, New Delhi, 110012
Seeds of three varieties viz; Pusa Red, Pusa Ratnar and White Warangal were mutagenised with gamma-rays, EMS, NMU and EI to determine their mutagen sensitivity and mutability. Low doses of some mutagens induced stimulatory effects on seedling height and bulb weight. The increasing doses of mutagens decreased germination, seedling height, survival, bulb weight and seed setting. The damages due to mutagens were not similar in thee onion varieties. However, the variety White Warangal suffered more damages due to reduction in respect of bulb weight and plant survival which were scored in later stages of plants indicating the presence of some recovery mechanism in onion. Spontaneous chlorophyll mutations frequented in all the three varieties and the irradiation of seeds with 12.5 kR gamma-rays increased the induced mutations rate to 14 times.
