Variation in physiological traits in Jatropha germplasm from peninsular India

Thirty-four diverse accessions of Jatropha curcas L. were studied for physiological parameters viz., net photosynthesis (Pn), stomatal conductance (g s ), transpiration rate (E) and leaf temperature difference (ΔT) and exhibited significant variation under semi-arid field conditions. The mean net photosynthesis (Pn) was 15 μmol m −2 s −1 and maximum net photosynthesis was recorded by IC537862 (24 μmol m −2 s −1 ). Accession, IC544693 recorded highest stomatal conductance and transpiration rate of 0.77 and 8.81 mmol m −2 s −1 respectively, whereas accession IC537877 showed lowest value of 0 for both of these traits. Correlation studies showed linear positive relationship between Pn and g s ( r = 0.72) and Pn and E (0.77). Based on the physiological traits, accessions suitable for moisture limiting conditions viz., IC471314, IC541660 and irrigated conditions viz., IC537862, IC537914, IC565044, IC565048 were identified. Multivariate cluster analysis helped in identification of physiologically diverse accessions viz., IC565048, IC550849, IC537869 and IC 544654 which were suitable for incorporation in breeding programmes.