Impact of ionising irradiation on physio-biochemical traits of Kinnow mandarin

Abstract

In our study, Kinnow mutants developed by exposing bud-wood to gamma rays at a dose range from 15-30Gy showed both stimulatory and inhibitory responses and even within the mutants developed with same dosimetery variations were observed. Irradiation exceeding 15Gy augmented the magnitude of radiation advantage for recording the maximum alteration in the physiological and biochemical traits in the putative mutants. Compared to wild type (WT), leaf area was recorded maximum and minimum in the mutants G6 and G14 developed from 20 and 25Gy. Photosynthetic pigments, chlorophyll a and b were degraded maximum in mutant G20 developed from 30Gy, while total phenol was stimulated in the mutants G18-G20 derived from 30Gy. Proline accumulation was higher in G14 and G15 and total soluble protein (TSP) in G15 developed from 25Gy. Antioxidant enzymes (SOD, CAT, POX and GR) were up-regulated maximum in the mutants generated from a higher dosimetery of 30Gy. Collectively these results confirm the dosimetry effects of irradiation on alteration of physiological and biochemical traits which can be used as a pre-selection criterion for selecting desirable mutants.