Asian Research Thesis Index

Abstract

Wheat crop is a basic staple food in many of countries all over the world. To overcome the need and supply gap of food it is necessary to improve wheat yield against different stresses such as heat stress. This study was performed to enhance the knowledge about genetics of heat tolerance in wheat using different agro-morphological parameters for screening of wheat. Line × tester mating design was used to access the genetic variability of wheat for combining ability against normal and heat stressed conditions. One hundred twenty genotypes were sown in research area of Wheat Research Institute (WRI) of Auyb Agriculture Research Institute (AARI) Faisalabad during growing season of 2014-15 in field and tunnel, which was covered during grain filling stage to provide high temperature stress. Ten lines and five testers were selected after proper screening by using different screening parameters such as cell membrane thermostability, normalized difference at vegetative stage, canopy temperature at vegetative stage and relative water content. The selected lines and testers were crossed in Line × Tester mating fashion. In next growing season (2015-16), parents along with their F1 hybrids were sown in triplicated randomized complete block design (RCBD) under normal and tunnel conditions. Data were recorded for both normal and heat stressed conditions for following traits i.e. cell membrane thermostability, normalized difference at vegetative stage, normalized difference at grain filling stage, canopy temperature at vegetative stage, canopy temperature at grain filling stage, relative water content, plant height, flag leaf area, peduncle length, spike length, number of fertile tillers per plant, days to heading, days to maturity, spikelets per spike, grains per spike, thousand grain weight, grain yield per plant and other quality traits like protein , moisture contents, starch, ash, gluten and test weight. Combining ability as used to investigate genotypes with best GCA and SCA. These parameters can help breeders in wheat crop improvement. All traits in this study showed dominance type of gene action under both normal and heat stressed environments. Results showed that the parents V-12103, Miraj-08, Faislabad-08, V-12082, Millat-11 and Chenab-2000 were good general combiner for grain yield and quality traits under both normal and heat stressed conditions. Among different crosses, V-13013 × ND643, SW89.52277 × Chenab-2000 and V-13013 × V-12082 showed better performance for grain yield and quality related traits that can be used in further breeding program for improvement of grain yield and quality parameters of wheat.

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