Analysis Of Wheat(Triticum Aestivum L.)Adaptability To Different Climate And Environmental Conditions

Atmospheric CO₂ concentration and temperature are two important environmental factors that are affecting crop growth and development.The change of climate will be accompanied by the increase of CO₂ concentration and temperature in the future.Wheat is the main grain crop in China,so it is important to study the adaptability of wheat growth and yield formation to the environment of CO₂ concentration and temperature rise in the future.This experiment used an open-top air chamber(OTC)to simulate an environment where the CO₂ concentration rises and the tempeature rises in the future,used field water holding capacity to control moisture,and the rain-fed and irrigated environments under the current natural climate conditions.There were four environmental treatments: normal CO₂ concentration-normal temperature-irrigation(E1),normal CO₂ concentration-normal temperature-drought(E2),high CO₂concentration-high temperature-irrigation(E3),high CO₂ concentration-high temperature-drought(E4).Different stay-green wheat varieties "Hanxuan 3" and "Yannong 19" were used as experimental materials to determinate the physiological indexes,dry matter accumulation in different organs above ground,yield at maturity and agronomic characters.Thre GGE biplot was used to evaluate different climatic environments,and the adaptability analysis of wheat to different climate and environmental conditions was conducted to provide a basis for the selection of strategies for wheat production to adapt to future climate change.The main findings were as follows:1.Under the environment of high CO₂ concentration-high temperature-irrigation(E3),the Pn,Gs,Tr,Ci and WUE of wheat leaves were higher than those of the other three environments,and the Pn,Gs,Tr of wheat leaves between the E3 environment and the other three environments reached significant levels in most stages of growth.The environment with high CO₂ concentration and high temperature could make up the negative effect of drought on crop photosynthesis,and had a greater impact on Pn and ci,especially the Pn of wheat leaves.The moisture content had a great effect on Gs,Tr and WUE.2.The chlorophyll fluorescence parameters of wheat in E3 environment were the best.The high CO₂ concentration and high temperature environment could effectively slow down the decline of chlorophyll fluorescence parameters of wheat,and it was more beneficial to the process of leaves photosynthesis during the grain filling stage.Fv'/Fm',Y(II),Fv/Fm,NPQ and ETR were significantly affected by water,while q P was more regulated by CO₂ concentration and temperature.3.From jointing stage to maturity,the SPAD content was the highest,the maximum senescence rate was the lowest,and the time of reaching the maximum rate was the latest in E3 environment.The time from the beginning of Senescence to the end of Senescence was the longest in the E3 environment.Regardless of drought or irrigation,high CO₂ concentration and high temperature environment could significantly increase the SPAD content of wheat leaves and delay the Senescence of wheat functional leaves.4.Under the condition of normal CO₂ concentration-normal temperature-irrigation(E1),the dry matter accumulation in all organs of wheat was the highest,followed by the E3 environment.Water was the most important factor to determine dry matter accumulation in wheat.The dry matter accumulation in E3 and E1 was significantly higher than that in E2 and E4 at the mid-late phase of grain filling.Under drought condition,high CO₂ concentration and high temperature environment had a great effect on dry matter accumulation,especially the dry matter accumulation on leaves.The high CO₂ concentration and high temperature environment will make crops distribute more dry matter to the grains;and the distributive ratio of dry matter in grains was the highest under E3 environment.5.Under the environment of E1,all the agronomic characters of wheat were better,and the accumulation of biological yield was the highest.However,under the environment of E3,the grain filling time was the longest,the dry matter accumulation was the largest,the 1000-grain weight was the largest,the harvest index was higher,the economic yield was highest,and the economic yield in E1 and E3 environments were significantly higher than in E2 and E4 environments.The high CO₂ concentration and high temperature environment will improve the agronomic traits and yield-related traits,and effectively make up for the loss of yield-related traits caused by drought.But water is the main factor that determines the agronomic and yield-related traits of wheat.6.Under the environment of high CO₂ concentration-high temperature-irrigation(E3),increasing the chlorophyll content of wheat leaves to delay the senescence of leaves will be more beneficial to the process of photosynthesis,improve the agronomic traits and yield-related traits of wheat,increase the distributive ratio of dry matter in grains,and finally obtain the higher economic yield.Therefore,the high CO₂concentration-high temperature-irrigation(E3)environment is most suitable for wheat growth.And under the condition of high CO₂ concentration-high temperature-drought(E3),higher CO₂ concentration can effectively improve the SPAD content,Pn,q P and dry matter accumulation ability of wheat leaves.It can improve the agronomic traits and yield-related traits,and make up the loss of yield caused by drought.