Effects of drought and high temperature stress on synthetic hexaploid wheat

Drought and high temperature often occurs simultaneously, causing significant yield losses in wheat (Triticum aestivum L.). The objectives of this study were to: (i) quantify independent and combined effects of drought and high temperature stress on synthetic hexaploid wheat genotypes at anthesis and at 21 days after anthesis; and (ii) determine whether responses to stress varied among genotypes. Four synthetic hexaploid and two spring wheat genotypes were grown from emergence to anthesis (Experiment I) and emergence to 21 days after anthesis (Experiment II), with full irrigation and 21/15°C day/night temperature. Thereafter, four treatments were imposed for 16 days as (a) optimum condition: irrigation + 21/15°C, (b) drought stress: withhold irrigation + 21/15°C, (c) high temperature stress: irrigation + 36/30°C and (d) combined stress: withhold irrigation + 36/30°C. Results indicated a decrease in leaf chlorophyll, individual grain weight and grain yield in an increasing magnitude of drought < high temperature < combined stress. There were 69, 81 and 92% grain yield decreases in Experiment I and 26, 37 and 50% in Experiment II under drought, high temperature and combined stress respectively. Synthetic hexaploid wheat genotypes varied in their response to stresses. Genotypes ALTAR 84/AO’S’ and ALTAR 84/Aegilops tauschii Coss. (WX 193) were least affected by combined stress in Experiments I and II respectively. Overall, combined effect of drought + high temperature stress was more detrimental than the individual stress and the interaction effect was hypo-additive in nature.

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Growth and yield components of wheat genotypes exposed to high temperature stress under control environment

Bangladesh Journal of Agricultural Research ◽

10.3329/bjar.v34i3.3961 ◽

1970 ◽

Vol 34 (3) ◽

pp. 360-372 ◽

Cited By ~ 23

Author(s):

M Ataur Rahman ◽

Jiro Chikushi ◽

Satoshi Yoshida ◽

AJMS Karim

Keyword(s):

High Temperature ◽

Grain Yield ◽

Temperature Stress ◽

Yield Components ◽

High Temperature Stress ◽

Relative Performance ◽

Growth And Yield ◽

Wheat Genotypes ◽

Heat Susceptibility Index ◽

Green Leaf Area

High temperature stress during grain-filling period is one of the major environmental constraints limiting the grain yield of wheat in Bangladesh. Crop growth response and relative performance of yield components of ten wheat genotypes were studied in two temperature conditions in glass rooms in a Phytotron to identify the genotype tolerant to high temperature stress. A favourable day/night temperatures of 15/10, 20/15, and 25/20°C were maintained from sowing to 60 days after sowing (DAS), 61 to 80 DAS and 81 DAS to maturity, respectively, in one glass room (G1); whereas day/night temperatures in another glass room (G2) was always maintained at 5°C higher than that of G1. Green leaf area and number of tillers in different times, number of days for the occurrence of major crop growth stages, relative performance in yield components, grain yield and heat susceptibility index were estimated following the standard methods. The higher temperature enhanced plant growth, flowering, and maturation. Thus the number of days to booting, heading, anthesis, and maturity of wheat were significantly decreased that varied among the genotypes. Green leaf area and productive tillers/plant were drastically reduced in time under high temperature. The reduced number of grains/spike and smaller grain size resulted from drastic reduction in growth duration were responsible for the yield loss of wheat at high temperature. Out of ten wheat genotypes, three were characterized as high temperature tolerant based on their relative performance in yield components, grain yield and heat susceptibility index. Key Words: High-temperature tolerance, wheat genotype, growth and yield components. DOI: 10.3329/bjar.v34i3.3961 Bangladesh J. Agril. Res. 34(3) : 361-372, September 2009

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