Biochemical and physiological constituents and their correlation in wheat (Triticum aestivum L.) genotypes under high temperature at different development stages

Wheat is the most popular and staple food for millions of people. It is severely affected by heat stress in many countries. Vegetative growth and reproductive phases in wheat differ in their sensitivity to temperature. Heat tolerant (GW-190) and Heat susceptible (J-2010-11) genotypes grown up to tillering and grain filling stages and Heat treatments (40°C and 45°C for 2h and 4h) were given using Heating House. After heat treatment samples were collected, the biochemical and physiological analysis such as Protein, Proline, Glycine betaine, Membrane stability, Relative water content, Germination percent, Seed vigour and Heat tolerant index were performed. Protein, proline and glycine betaine were found significantly highest 34.06 mg/g Fr. Wt., 13.70 mg% and 902.24 µg/F. wt respectively in heat tolerant genotype GW-190 at 45°C for 4 h at tillering stage. Membrane stability and relative water content were found significantly highest 56.83% and 86.15 % respectively in heat tolerant genotype GW-190 at tillering stage. Germination percent, Seed vigor and Heat tolerance index were found higher in control group of Heat tolerant GW-190 genotypes. Where, all the biochemical and physiological contents were found lower in heat susceptible J-2010-11 genotype. From the above results it was concluded that GW-190 was heat tolerant genotypes which is suitable for grown in area of high temperature and J-2010-11 was found heat susceptible.   Key words: Relative water content, membrane stability, seed index, heat tolerant index, correlation.