Effect of gamma-rays on vegetative and flowering parameters of chrysanthemum

The rooted cuttings of ten chrysanthemum cultivars namely Ajay, Baggi, Bright Golden Anne, Ellen Van Langen, Glance, Gulmohar, Mountaineer, Nanako, Shyama and Snow Ball were exposed to gamma-rays treatments (0 and 2.0 k rads; Source: CO60). These gamma-irradiated rooted cutting alongwith untreated cuttings were planted under field condition. The radio-sensitivity of these cultivars was determined on the basis of various vegetative and floral characteristics of the treated plants. In general, there was a significant reduction in plant survival, plant height, growth, number of branches, leaf number, leaf size, plant spread, number of flowers flower size etc., and increase in plant abnormalities (foliage and floral), days to bud formation, days to reach the harvesting stage and ratio of disc:ray florets per head was recorded in all cultivars with 2.0 k rads of gamma-rays treatment as compared to control (i.e. 0 k rads). The somatic colour mutations were induced in Ellen Van Langen, Gulmohar, Snow Ball and Shyama.