水保所知识产出(1956---)知识库

Crop avoidance and tolerance strategies are critical adaptive mechanisms of drought
stress and play different roles in grain yield. However, little is known about the contribu-
tion of these two mechanisms to grain yield in old and modern wheat genotypes. Here,
pot and field experiments were carried out to characterize and compare the mecha-
nisms of drought avoidance and drought tolerance, and determine their differential con-
tributions to the yield in six wheat genotypes. The pot experiment results demonstrated
that the old genotypes acquired a better avoidance ability to adapt to drought stress.
These avoidance abilities include larger root systems, lower leaf areas, low stomatal con-
ductance, pale green leaf colour, higher degrees of leaf rolling and leaf waxiness. The
modern genotypes displayed stronger drought tolerance advantages, such as high os-
motic adjustment and antioxidant enzyme activity, and a smaller root system. Our field
experiment further showed that under severe water- deficit conditions, the old geno-
types with stronger drought avoidance traits had higher yields and water use efficiency
(WUE g ), whereas the modern genotypes with strong drought tolerance characteristics
produced higher yields and had higher WUE g under mild and intermediate water defi-
cits. The results indicate that the relative contribution of drought tolerance and drought
avoidance to grain yield depends to a large extent on the degree of drought stress and
genotypes. Understanding the differential plant response depending on genotype and
drought stress may help plant breeders develop drought- resistant varieties suitable for
drought- prone environments under anticipated climate change scenarios.