Differentiate Contribution Of Typical Physiological And Morphological And Anatomical Traits To Yield Formation And Its Evolutionary Characteristics In Dryland Wheat

Water is the major abiotic element that affects crop growth and reproduction in arid areas.Using morphology,physiological and biochemical indicators to reveal the response of drought has important theoretical significance for crop breeding in arid areas.The study was carried out at the Yuzhong Campus of Lanzhou University from 2014 to 2016.By setting different water treatment,the main indicators of determination of morphology,physiology and yield of wheat,to reveal the effect of drought stress on yield and water use efficiency and the mechanism of wheat formation.The main results are as follows:1.Effects of different drought stress on water use efficiency and yield in two root type of spring wheatHeshangtou(HST,large root)and Longchun 8275(LC8275,small root)were used as the materials.The results showed that under different drought stress,the yield reduction rate of HST was lower than small root system LC8275,and the water use efficiency for yield were increased with the increase of drought.Meanwhile,allometric relationship analysis showed that,under the well water,the allometric growth index of grain yield(R)and vegetative biomass(V)of HST increased significantly more than 1,indicating that HST will use more energy for the grain,but under drought stress,the index of R-V is no significant with 1,showed that drought stress changed the reproduction strategy of HST.But for LC8275,in the water treatment,the index of R-V are not changed significantly,so,it was concluded that HST was more sensitive to drought.2.Effects of two water treatments on water use efficiency and yield of different ploidy wheatUsing 8 different ploidy wheats as the materials,the results showed that with the increase of ploidy that the yield and water use efficiency for yield(WUEyield)showed an increasing trend.Compared with well water,drought reduced the yield,and improved water use efficiency.Under moderate drought,the yield of different ploidy wheat were decreased by 36%,47.2%,40.1%;and WUEyield were increased by 2.1%,4%,4.1%.Allometric relationship analysis showed that under well water,the index of R-V for hexaploid wheat was greater than 1,indicating that hexaploid wheat increased with body size,reproductive output also increased;while under drought stress,the allometric growth index of diploid wheat significantly greater than 1,means under drought stress,diploid wheat output is increased with the increase of the size of the plant.The tetraploid wheat in this two water treatment,the allometric growth of R-V index with 1 were no significant difference,therefore,under different water environment,the reproductive allocation strategy of wheat are different.3.Effects of water stress on morphological and physiological traits of wheatDrought caused the decline in yield,one is changed the pattern of biomass distribution,and on the other hand,through the morphological and physiological traits caused by the impact of wheat production.The results showed that root / shoot ratio increased with drought stress,and tiller number,plant height,ear length,leaf area,leaf biomass,root biomass were decreased under drought stress.The anatomical structure such as leaf thickness,epidermis thickness,vascular bundle diameter,thickness of vascular sheath and so o wwre reduced significantly.And the content of proline,soluble sugar and soluble protein were increased.In study,the proline,soluble sugar and soluble protein indicator are defined as drought tolerance indicators,and the root biomass,root / shoot ratio,plant height,leaf area,vessel diameter,vascular sheath thickness,vascular bundle diameter,etc.classified as drought avoidance indicators.4.Differentiate contribution of typical physiological and morphological and anatomical traits to yield formation under water stressThe results showed that contribution largest to wheat yield is the morphological traits,including effective tiller number,the vegetative organ biomass,spikelet number,grain numbers under drought stress;and leaf anatomic index,such as leaf epidermal thickness,vascular diameter and physiological traits on yield are smaller.However,with the increase of ploidy,the correlation between physiological characters,anatomical characters and yield was increasing.