Physiological alteration in Kinnow developed through physical and chemical mutagen

Abstract

Alteration in plant growth, fruit yield and leaf gas exchange characteristics such as photosynthetic rate (A), stomatal conductance (gs), transpiration rate (E) and intercellular CO2 concentration (Ci) were investigated in five year old putative Kinnow developed from different doses of gamma irradiation and chemical mutagen (EMS) and compared with wild type (WT). The result showed dose-dependent decrease in plant height and yield in the developed from higher dosimetery. The plant height in the (G17-G20) developed from 30 Gy was inhibited by > 45.0%, while in the Eand Edeveloped from 0.02 and 0.05% EMS, it was reduced by >24%. Fruit yield was reduced by 66% in the G18 and G20 developed from 30Gy and >50% reduction in fruit yield were noted in E6 and E8 developed from intermediary dose of 0.1% EMS. Leaf gas exchange parameters recorded during different seasons of the year (April, August and December) exhibited differential response. Photosynthetic rate as compared to the wild type was reduced in the mutagenic population and maximum reduction without any seasonal variation were observed in the G12(4.92, 5.20 and 4.92 μmol m−2 s−1) and G13(4.98, 5.04 and 4.96 μmol m−2 s−1) developed from 25 Gy. Amongst the developed from chemical mutagen, photosynthetic rate was minimum in mutant E13 (5.15, 5.27 and 5.09 m−2 s−1) developed at EMS 0.2%. Both stimulatory and inhibitory response were observed in the magnitude of transpiration rate, stomatal conductance and leaf intercellular CO2 in the developed from higher doses of gamma rays and EMS. The result demonstrated that physiological alterations can also play a role in characterising genetic variability and pave way for selecting putative for future use in the breeding programme.