Gamma-rays Induced Morphological Changes in Chrysanthemum. (Chrysanthemum morifolium)

Abstract

The purple color clone of spray type chrysanthemum available as pot plant in the market was used to study the effect of gamma radiation on in vitro culture of chrysanthemum (Chrysanthemum morifolium). Ray-florets were cultured on the MS medium containing 10 mg/l BA. Multiple shoots produced were irradiated with gamma rays at 0, 10, 30, 50, 70, 90 and 110 Gy. Subculturing was carried out three times from M₁V₁ to M₁V₄ after which M₁V₄ shoots were rooted and transplanted to the greenhouse. M₁V₄ shoots irradiated at 50 Gy and over died within 25-30 days. LD₅₀ for this purple clone of chrysanthemum was 14 Gy. Only the controls and treated plants at 10 Gy were able to survive and gave rise to the full grown plants. After transplanting into the greenhouse for 60 days, control plants and treated ones were found to be different in four traits which were average height, average number of leaves, average number of nodes and % flowering. Plants were trimmed twice at three month intervals and allowed to produce flowers. Changes in flower characters were found in both controls and treated plants. However, the treated plants had much more variation than the controls and new flower color (yellow tinge) was only obtained from the treated ones.