Abstract:

Adequate dry matter production of plants is a very important event for producing higher grain yields under high temperature stress. We established a field trial to measure differences in dry matter accumulation of different plant parts of wheat under normal and high temperature conditions. Two temperature regimes were provided by planting at two different times (normal wheat sowing time and quite late time to receive warmer conditions). Also two different irrigation regimes has been applied to distinguish the impact of drought from temperature.   As a result of trials, dry matter content was maximum at lower stem and minimum at flag leaf both at anthesis and maturity. When different growth conditions compared, total dry matter content was lowest at high temperature rainfed conditions except lower leaves at maturity. This value was maximum at normal temperature rainfed condition at anthesis and high temperature irrigated condition at maturity. Instead of existence of enough dry matter for producing high grain yield levels, harvest index was minimum under high temperature irrigated condition. As a result, grain yield was minimum under high temperature irrigated condition (4.65 t/ha). Grain yield was maximum at normal temperature rainfed condition (6.20 t/ha). This indicates an exsistance of a problem other than adequate dry matter production to produce more yield under high temperature conditions.

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