Effect of ionizing radiation on morphological characters and leaf nutrient content of sweet orange cv. Mosambi

In the present study, sweet orange cv. Mosambi mutants were developed through treating bud stick with different doses of gamma irradiation (10, 15, 20, 25, 30 and 35 Gray) and budded in situ on Jatti Khatti rootstock. Two years after the establishment of plants, the impact of ionizing radiations on the mutated population was studied for the alterations in growth and plant nutrient status, showing differential stimulatory and inhibitory dose dependent responses. Mutants developed with lower doses of gamma irradiation stimulated plant height in the mutants GS-3 (39.30 per cent) and GS-8 (40.80 per cent) developed from 15 and 20 Gy, respectively. Contrary to the stimulatory effects, higher irradiation doses inhibited plant height and other growth parameters in the mutants GS-16, GS-30, GS-32 and GS-34 developed from 35 Gy. The macro-nutrient concentrations were higher at lower doses of 10 and 15 Gy in the mutants GS-2, GS-3 and GS-8, while the micro-nutrient contents in the leaf tissue were higher in the mutants GS-21 and GS 14 developed from intermediate doses of 20 and 25 Gy. Although lower accumulation of macro-nutrients was observed at higher dosimetery, however, reverse trend was noticed with respect to the micro-nutrients, being minimum at the lowest dosimetery i.e., 10 Gy.