Mutagenic Effects of Gamma Rays on Young, Middle and Old age Stem Cuttings of Poplar (Populus deltoides) in Spring Season

Three different age group stem cuttings of P. deltoides viz.6 month (young age), 12 month (middle age), and 24 (old age) months have been selected in the present investigation to investigate their regeneration sensitivity after treated with different continuous and fractionated doses of gamma rays. Treated cuttings have been planted in the first week of March when mother plant has got started to sprout after winter dormancy. Maximum sprouting percentage (66.6 %) has been recorded under 2KR-C level in young age stem cuttings than the middle and old age. Under fractionated treatment 500r-F was found more effective in sprouting percentage and it was recorded 60 % sprouting. Combination effects of gamma rays with 500ppm showed antagonistic effects for different parameters in all the three age treated cuttings. Different parameters for lateral shoot growth and mortality percentages of the sprouted bud have also been observed during regeneration. At 2KR-C level maximum shoot length 70.5 cm have been recorded and this is followed by 4KR-C level 58.5cm. The area of leaf was favoured higher at lower continuous doses of all the treated cuttings.