Effect of Pre-Anthesis Drought Hardening on Post-Anthesis Physiological Characteristics,Yield and WUE in Winter Wheat

A drought event can cause yield loss or entire crops to fail.In order to study the effects of continuous drought on physiological characteristics,yield,and water use efficiency(WUE)of winter wheat(Triticum aestivum L.),the variety“Zhoumai 22”was grown in controlled water conditions of the pot-planted winter wheat under a mobile rainout shelter.Foot planting and safe wintering were used to evaluate,winter wheat under different drought conditions,including light,moderate and severe drought at the jointing,heading,and filling stages.The soil water content was controlled at 60–70%,50–60%,or 40–50%of field capacity.Experimental trials included 3 pre-anthesis drought hardening,3 three-stage continuous drought,and 1 test control conditions.Under drought stress conditions,winter wheat leaf water potential,soil plant analysis development(SPAD),photosynthesis parameters,and yield declined due to pre-anthesis drought hardening.And the degree of decline:continuous drought>pre-anthesis drought hardening.Changes in the post-anthesis photosynthetic capacity of winter wheat were mainly related to the pre-anthesis drought level,rather than post-anthesis rehydration.The threshold of non-stomata limiting factors caused by photosynthesis at the filling stage is 40–50%FC,while comprehensive yield and WUE affected,the yield in severe drought treatments was the most significant,B3C3 and B3C3G3 decreased by 55.68%and 55.88%,respectively.Pre-anthesis drought was the main reason for the decreased crop yield.Thus,severe drought should be avoided during planting,while pre-anthesis light drought is a suitable choice for watersaving and crop production,as proper pre-anthesis drought hardening(60–70%FC)is feasible and effective.

Effects of Multi-Stage Continuous Drought on Photosynthetic Characteristics, Yield and Water Use Efficiency of Winter Wheat

A drought event can cause entire crops to fail or yield loss.In order to study the effects of continuous drought on photosynthetic characteristics,yield,and water use efficiency(WUE)of winter wheat(Triticum aestivum L.),the winter wheat variety“Aikang 58”was selected as test material with controlling the water of the pot-planted winter wheat under a mobile rainout shelter.Based on foot planting and safe wintering,winter wheat was evaluated under different drought conditions,including light,moderate and severe drought at the jointing(B),heading(C),and filling(G)stages.The soil water content was controlled in a range of 60%to 70%,50%to 60%,and 40%to 50%of the field capacity,respectively.In the experiment,there were 9 single-stage droughts,3 three-stage droughts,and 1 test control(totaling 13 trials).The results are as follows:Under a single-stage drought,the change of net photosynthetic rate(Pn)and stomatal conductance(Gs)have similar trends,and they both decrease significantly with the severity of the drought.Under three-stage continuous droughts,the change curve of Gs shows a constant downward trend;the change curve of Pn showed a“valley shape,”and the minimum value of Pn appeared at the heading stage.All droughts will reduce the yield of winter wheat.Under the three-stage continuous drought conditions,except for light drought,moderate drought and severe drought will cause significant yield reduction,mainly due to lack of water at the jointing and heading stages.Continuous drought will reduce the WUE,and the difference will reach a significant level under moderate and severe drought.The present results suggested that when water resources are scarce,it is a better irrigation model to save water and achieve high grain yield by applying appropriate water stress(60%–70%FC)during the critical growth period of winter wheat.

Effects of water and nitrogen coupling on growth,physiology and yield of rice

Water and nitrogen fertilizer are two essential factors for quality and yield formation of rice.Experimental study was carried out to investigate the effects of water and nitrogen fertilizer coupling on yield-related factors,such as growth(height),physiological indicators(chlorophyll and leaf area index(LAI))and yield composition indicators(productive panicles,thousand grain weight and total grains per panicle).Results showed that,the height difference under two irrigation regimes was not significant,and it showed no difference until the tillering stage(p>0.05).The water control method for controlled and mid-gathering irrigation(CMI)was favorable for nutrients converting to rice grain.Meanwhile the height difference for CMI and conventional irrigation(CVI)was the biggest at 80 d after rice transplantation.Variance analysis showed the effect of fertilization on height was significant(p<0.05).With organic fertilizer application,it could control plant growth and promote the nutrients converting to the panicle.The change curve of LAI was similar to chlorophyll content.Organic fertilizer application could not only promote chlorophyll content and LAI,but also delay leaf fading and promote yield.Nitrogen fertilizer factors showed significant difference on rice yield,compared to irrigation regimes showing no significance.Considering the irrigation and fertilizer factors together,the interaction was significant.The descending orders for the effects of water and nitrogen on rice yield were fertilizer,water and fertilizer,water.Regression analysis showed that the productive panicles and total grains per panicle of rice were extremely significant on rice yield,and the direct effect of total grains per panicle on yield was greater than that of productive panicle.This study results could provide theoretical basis for water and nitrogen management to improve rice production.