Radiosensitivity of Populus deltoides middle aged clones (12 months) to gamma rays and its synergistic effects with stik

Abstract

The middle-aged stem cuttings of Populus deltoides (chromosomes No. 38) were irradiated with different continuous and fractionated doses of gamma rays (500r, 01, 02, 04 krd.) during the month of September to observe sensitivity of sprouting and shoot growth behavior. Some irradiated cuttings were also treated with Stik 500ppm to observe its antagonistic and protagonistic effects on regeneration of cuttings. Maximum sprouting percentage was recorded under the 1KR-C (83.3%) followed by 4KR-F (54.5%) while control sprouted only (43.7%). Continuous doses proved to be most promising for mutation breeding, having abnormal size of leaf, increased number of leaves and enhanced length of the lateral branch. Maximum length of lateral branch was recorded under the treatment of 500 R-F (4.5 cm ± .15). Stik 500ppm, showing protagonistic effects at all the lower continuous and fractionated does while higher C&F doses indicating antagonistic effects on different parameters i.e. sprouting percentage, length of the lateral branch, number of leaves per cutting and size of the leaves. The mortality percentage of sprouted buds was recorded and it was maximum 85.8% in 4 KRC treatment.