Research On Physiologic And Genetic Of Water Use Efficiency (WUE) And Relative Traits Of Wheat

The research and breeding for drought resistance and water saving in Wheat (Triticum aestivum L.) is an important project in water saving agriculture. Breeding for high water use efficiency (WUE) can combine drought resistance, water saving and high yield abilities. It is valuable to research WUE using physiologic and genetic technology to screen some orrelative physiologic and genetic traits which can improve water use efficiency.Twenty wheat genotypes with different drought resistance and a substitution line derived from a cross between two common wheat varieties Chinese spring and Red Egyptian were used in this research to measure WUE and some related traits, and preliminarily screen out some physiologic and genetic traits which were close to WUE, and preliminarily located some genes of drought resistance and water saving traits and Agronomic trait in chromosomes. The major results are described as follows:1 There was significant linearity positive correlation between leaf WUE and Pn,and between Tr and Cond, but significant linearity negative correlation between LWUE and Tr and Cond and ψw and RWL. But there was insignificant positive correlation between leaf WUE and other four traits including anti-oxidative enzyme activities and wax content and Tleaf (leaf surface temp) and insignificant negative correlation between leaf WUE and RWC (relative water content).2 Several drought resistance and water saving related traits were measured using the substitution line during several different Growth duration. The results showed that the genes controlling high WUE were located possibly in chromosome 5A and 5D, high photosynthesis rate genes were located possibly in chromosome 3A and 3D, high transpiration rate genes were located possibly in chromosomal 7B ,and the genes which can improve and restrain the activity of POD were probably located in chromosome 7D and 3D respectively, genes which can improve the activity of SOD were probably located in 2B and 6D, besides , some genes which probably restrain the activity of SOD were located in chromosome 4A,5B,6A and 7B.3 The results showed that the genes controlling height were related to chromosomes 3D, 4A, 4D, 5D, 6A, 6B and 7D, among them, the effects of genes in chromosomes 4A, 4D, 6A, 6B and 7D were obviously larger than those in other chromosomes; and genes controlling spikes were related to chromosomes 7B; and genes controlling spike length were related to chromosomes 1-4B, 6-7B, 3D, 6A, 6D and 7D, there are seven major genes in chromosomes 2-4B, 6B, 6A, 6D and 7D, at the same time, there are genes restraining spikes length in chromosomes 2D; and genes controlling spikelet number were related to chromosomes 2D,4A,4D,5D,6A,6D and 7D, the effects of genes in chromosomes 5D an 6D were obviously larger than those in other chromosomes; and genes controlling biomass yield were related to chromosomes 6B and 7B, the effects of genes in chromosomes 7B were lager than that in chromosomes 6B; and genes controlling 1000-grain weight were related to chromosomes 4A, 5A, 5D, 6A, 6B, 6D and 7B, there are one major gene in chromosome7B.4 In this research, the total water use efficiency (TWUE), root water use efficiency (RWUE) and root dry weight (RDW) of most wheat varieties which have drought resistance increased under PEG stress, but the shoot water use efficiency (SWUE) and the shoot dry weight (TDW) decreased. It showed that drought stress really reduced the accumulated rate of dry weight of wheat, and influenced the growth of canopy seriously. Furthermore, it distributed more assimilate to root, it made RWUE, RDW and R/S rate increased.