Wheat environmental protection and photosynthetic stress crop physiology
2001
Kershanskaya, O.I. (Institute of Plant Physiology, Genetics and Bioengineering, 45 Timiryazev Str., 480090, Almaty (Kazakstan))
An important objective of wheat crop improvement breeding program is to use physiological information on the genetic basis of differences in reaction to stress to improve production under drought conditions. A possible character that may be important in drought tolerance is a strategy of photosynthetic apparatus adaptation to stress and genetic manipulation of photosynthesis. The photosynthetic responses of Kazakstan wheat hybrids and rolling leaf (RL1 and RL2) lines were evaluated in 2 cycles of drought modulated pot experiments in a glasshouse and in the field conditions. Measurements were made of soil moisture content, leaf water potential, leaf gas exchange, chlorophyll flourescence. Genetic aspects of photosynthetic characteristics were estimated. Different genotypes responded differently to the first and the second drought period, too. The chlorophyll florescence data indicated that the efficiency of PS11 was relatively little affected by the stress treatment, however, the qNP increase was greatest in drought resistant genotypes. Leaf rolling had a greater effect on photosynthetic assimilation than on water loss, hence reducing the potential water use efficiency of these lines. Screening of wide selection material by photosynthetic indices and physiology - genetic manipulation of photosynthesis are described as tools to improve the efficiency of wheat breeding for increased drought resistance
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