PHYSIOLOGICAL AND BIOCHEMICAL TRAITS FOR IDENTIFICATION OF SALT TOLERANCE POTENTIAL IN FOUR SORGHUM GENOTYPES

Soil salinity is an alarming problem in the world and major hindrance to agricultural productivity. Adoption of salt tolerant genotypes and screening them in early stages of their growth has become much essential for better growth and yield. This study was conducted to explore the salinity induced changes in water and photosynthetic traits of sorghum cultivars. A sand culture experiment with four sorghum genotypes Sandalbar, JS-2002, Noor and FJ-115 was conducted in earthen pots containing 0 and 100 mM NaCl salinity solutions along with 1/5 Hoaglands nutrient solution. Salinity significantly inhibited leaf water potential in all four sorghum genotypes particularly in Noor and FJ-115 with 0.9 and 0.8 psi w-MPa respectively. Sandalbar and JS-2002 genotypes maintained higher transpiration rate than FJ-115 and Noor. The maximum inhibition in stomatal conductance was recorded in Noor (1.7 mmol m(-2)S(-1)) followed by FJ-115 (2.3 mmol m(-2)S(-1)). Under salinity stress, highest decrease in total chlorophyll (52.1%) and soluble sugars (0.26 mg g(-1) F.W) contents were found in FJ-115. Salinity stress negatively effected physiological and biochemical traits in all sorghum genotypes that can be used as indicator of their salinity tolerant potential. Sorghum lines JS-2002 and Sandalbar can be categorized as salinity tolerant while Noor and FJ-115 as sensitive for cultivation. This study could mark a way for determining the degree of salinity tolerance in sorghum cultivars for further utilization in breeding programmes.