Evaluation of wheat (Triticum aestivum L.) genotypes for senescence associated traits under late sown conditions
Loading...
Date
2014
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
Ten wheat genotypes under two dates of sowing Normal sown: 1) WH 711, 2) PBW 343, 3) PBW 621, 4) HD 2687 and 5) HD 2967and Late sown: 1) WH 1021, 2) WH 1100, 3) WH 1111, 4) PBW 373 and 5) PBW 590 were evaluated at four observation stages under normal sown and late conditions in two experiments. The first experiment was conducted in 2011-12 to screen out best four genotypes on the basis of physiological and yield traits. Based on the first experiment NS genotypes WH 711 and PBW 343 and late sown genotypes WH 1021 and WH 1100 were selected for next year sowing because of retaining green character for longer time, maintaining membrane integrity, cooler canopy temperature and higher yield. The second experiment was conducted in 2012-13 on four wheat genotypes to evaluate best genotype for senescence associated traits under late sown condition with inoculation of AM fungi and Azotobacter.
Photosynthetic rate, transpiration rate, chlorophyll stability and membrane stability decreased with late sown condition at reproductive stage. Inoculation of AM fungi alleviated values of these parameters under late sown condition and helped in maintaining cooler canopy and stays green for longer time. The genotype which performed well under late sown condition was WH 1021and least efficient genotypes was PBW 343. There was increase in antioxidants (ROS and MDA) and enhancement of antioxidant defense system to scavenge excess ROS molecules to prevent cell from damage. The main antioxidant enzymes which showed altered activity were catalase, peroxidase and superoxide dismutase. Protein structure was also altered at terminal high temperature stress and proteolytic enzyme protease showed increase in activity under late sown condition and growth stages. Ribonuclease activity decreased in late sown condition but increased with observation stages in all four genotypes. Genotype WH 1021 showed a distinct band of 86 kda when
inoculated with AM fungi at 14 DAA which might help in staying green for longer period to this genotype under terminal high temperature stress. Growth and yield parameters were also reduced under late sown condition while positive results in treatment of AM fungi were observed. Grain protein content was increased under late sown condition while starch content was decreased. AM fungi inoculation was more effective compared to Azotobacter treatment in all parameters. Among the four tested genotypes, WH 1021 performed better in terms of physiological, biochemical and yield related traits under late sown condition and maintained stay green characters by delaying senescence for longer duration during reproductive period under terminal high temperature stress.
Description
Keywords
wheats, developmental stages, genotypes, planting, fungi, enzymes, yields, grain, sowing, biological phenomena