Studies on gamma ray induced mutants in gladiolus

An experiment was conducted for 2 years (2011-12 to 2012-13) at Varanasi to find out the influence of various gamma rays doses, i e 1.5, 2.5, 3.5, 4.5 and 5.5 kr along with untreated (control) in different varieties of gladiolus, viz. Aldebaran, Jyotsna, Legend, Praha, Punjab Dawn, Pusa Kiran and Tiger Flame. Higher dose of gamma irradiation (5.5 kr) resulted in minimum sprouting. Maximum sprouting percentage was recorded with control followed by 1.5 kr, 2.5 kr, 3.5 kr, 4.5 kr and 5.5 kr. Gamma ray doses at 3.5 kr, 4.5 kr and 5.5 kr found were lethal in case of three varieties, i e Aldebaran, Legend and Praha and failed to produce any spike during 1st year. Early spike emergence (74.37 days) was recorded with 1.5 kr dose of gamma irradiation. Late opening of 1st floret (94.00 days) was observed with 2.5 kr of gamma dose. Flower opening was not observed at higher doses, i e 3.5 kr, 4.5 kr and 5.5 kr in cv. Pusa Kiran during 2nd year. Maximum number of flowers/spike was recorded with control which was at par with lower dose of gamma irradiation (1.5 kr). Gamma dose at 2.5 kr exhibited maximum durability of 2nd and 3rd florets. Maximum length of spike at the last floret opening was noticed in control (74.48 cm) followed by 1.5 kr, 2.5 kr, 3.5 kr, 4.5 kr and 5.5 kr. During both years 2.5 kr resulted in maximum duration of flowering. Treatment 4.5 kr resulted in abnormal plant growth, bunched spike in some plants of cv. Pusa Kiran. A mutant having creamish white colour was found at 2.5 kr in one plant of cv. Jyotsna. A colour mutant was observed in cv. Tiger Flame. This colour mutant produced yellow coloured florets at 3.5 kr treatment. One mutant had been found in cv. Punjab Dawn at 2.5 kr treatment. Flowers were white in colour, whereas, flower colour of parent variety Punjab Dawn is pink. Colour of the flowers was white during VM1 and it was found stable in VM2.