Induction of radiomutants in Chrysanthemum morifolhim Ramat. cv. Gul-e-Sahir for novel traits

Chrysanthemum is one of the most popular ornamental group of plants world over. Its wide range of brilliant colour, shapes, size, long lasting flower life, etc. makes it quite competitive in commercial floriculture. Here, we tried to estimate the efficiency of different doses of gamma rays to induce novel mutations in chrysanthemum cv 'Gul-e-Sahir' using terminal rooted cuttings as experimental material. The rooted cuttings were exposed to different doses of γ-rays (0, 10, 20 or 30 Gy) using a ⁶⁰Co source and transplanted in earthen pots (8''). Marked variations were recorded in leaf colour, leaf shape, flower size, shape and colour between the mutated and control populations. Four new flower colour variants with altered or novel flower colours were isolated that were unique and different from original flower colour. The original flower colour of Gul-e-Sahir is yellow whereas, flower colour of mutated population was of nearest shades of green yellow group as per RHS colour chart. The ray florets were normal in control whereas, in mutated population my florets were spoon shaped, narrow, broad, flat and tubular in shape. These mutants were further multiplied on large scale and evaluated to check their stability. This study developed a mutagenesis protocol that could be used to develop novel colour mutants in chrysanthemum. (author)