Effect of temperature stress studies on various biological growth parameters in wheat genotypes under semi-natural conditions

Abstract

Grain yield of wheat in Pakistan is low as it is severely affected by various biotic and abiotic stresses. Among the abiotic stress, heat stress (terminal high temperature) is one of the major causes of low wheat productivity in Pakistan. This paper focuses on the evaluation and performance of newly evolved wheat genotypes under different temperature regimes and the selection of suitable promising lines. Experiment was conducted under semi-natural conditions on twenty wheat genotypes (DH-1, DH-3, DH-4, DH-5, DH-6, DH-7, DH-8, DH-10, DH-11, DH-12, DH-13, DH-14, DH-15, DH-16, DH-18, DH-19, DH-20, DH-21, Lu-26s and Kiran-95) in wire gauze chambers at Nuclrear Institute of Agriculture, Tandojam, Sindh, Pakistan, during 2014-15. The genotypes were sown in three different dates viz., S1 (November 7, as optimum condition), S2 (November 27 as heat stress) and S3 (December 17 as high heat stress). All the plant growth parameters viz., plant height (cm), productive tillers plant-1, spike length (cm), spiklets spike-1, number of grain spike-1, grain weight plant-1 and 1000-grain weight (g) exposed significant variation among genotypes and temperature regimes based on their interactions and these showed significantly decreasing trend in heat stress conditions over optimum conditions. The genotypes DH-8, DH-11, DH-15, DH-19 and Lu-26s classified as tolerant exhibiting <50% reduction in 7 variables whereas, DH12 and Kiran-95 were sensitive showing <50% reduction in 4 variable. The genotypes DH-1, DH-4, DH-5, DH-6, DH-7, DH-13, DH-16, DH-18 were medium tolerant showing <50% reduction in 6 variables while DH-3, DH-10, DH-12, DH-14, DH-20 were found medium sensitive showing <50% reduction in 5 variables.