Effect Of Water On Yield And Main Trace Elements Of Colored-grain Wheat

Wheat is the main food crop in China,and it is also the main source of trace elements intake for the human body.Compared with white wheat,colored-grain wheat varieties(lines)are rich in trace elements,especially iron(Fe),zinc(Zn)and selenium(Se).Water is an important factor that affects the wheat yield and quality.Therefore,studying the influence of water on the yield and trace elements of colored-grained wheat is important to find the suitable water management measures of colored-grained wheat,achieve high-yield and high-quality nutrient production,and sustainable agricultural development.In this study,seven black wheat(’Zhouheimai 1’,’Heiyou 1’,’Yusheng 3’,’Zhengneng 2’,’Xinongheidasui’,’Hedongwumai’,’Xinongheimai’),blued-grain wheat(’Wanyu 202’),purpled-grain wheat(’Longzimai 2’)and white wheat(’Xinong 979’)(CK)were planted as the experimental materials.A split plot experiment with two factors was carried out under no irrigation(W0),once irrigation(W1,at the wintering stage)and twice irrigation(W2,at the wintering and jointing stage)environments to study the photosynthetic characteristics,yields,microelement content in grain,and microelement accumulation and distribution ratio in nutrition organs.The results showed that:1.The SPAD value of flag leaf after anthesis of colored-grain wheat showed a "parabola" trend,and reached the maximum at 14 days after anthesis.Compared with W0,irrigation environments significantly increased the flag leaf SPAD value(p < 0.05)and slowed down the decline of SPAD value at the late filling stage.Among them,white wheat had a larger drop in flag leaf SPAD value than colored-grain wheat,and among the colored-grain wheat varieties,’Wanyu 202’ had the largest decrease.The changes of net photosynthetic rate(Pn),stomatal conductance(Gs),and transpiration rate(Tr)of flag leaf after colored-grain wheat anthesis increased first and then decreased,while intercellular CO2(Ci)concentration had the opposite trend.Compared with W0,irrigation could alleviate the decline of flag leaf Pn,Gs,and Tr in the late filling stage of colored-grained wheat.The flag leaf photosynthetic efficiency of colored-grained wheat in the later stage of grain filling was higher than that of white wheat.2.Compared with W0,irrigation environments significantly increased the number of spikes and yield per unit area of colored-grained wheat(p < 0.05),but had little effect on the thousand‐kernel weight.Irrigation environments significantly increased the number of coloredgrained wheat spikes at the jointing stage.Under the three water treatments environments,the yield of white wheat was higher than that of colored-grain wheat.The yield of ’Zhouheimai 1’was the highest among colored-grain wheat varieties.Compared with W0,W1 and W2 environments increased by 3.48% and 4.90%,respectively.3.With the process of grain filling,the Fe content of colored-grain wheat grains showed a trend of first increasing and then decreasing;grain Cu showed a downward trend and then an upward trend;the Se content of grains showed a downward trend;there were differences among varieties in the changing trends of grain Mn and Zn.During the maturity stage,variety,water and their interactions had significant effects on the Fe,Mn,Zn,Cu,and Se contents of wheat grains(p < 0.01).There were differences among varieties in the effects of different water treatments on the content of Fe,Mn and Zn in colored-grained wheat grains.Compared with W0,Se content in the grain of wheat was increased significantly under W1 environments(p < 0.05).Se content in the grains of colored-grained wheat was increased under W2 environments,whereas that of white wheat was reduced significantly(p < 0.05),which suggests that irrigating at the wintering stage could be beneficial for Se content in the grain of colored-grained wheat increases.The Cu content in the grain of wheat was reduced significantly(p < 0.05),and the decrease of Cu content in the grain of colored-grained wheat was greater than that of white wheat.Under different water environments,the contents of Fe,Mn and Se in colored-grain wheat were higher than those in white wheat.The content of Fe,Mn,Zn and Se in ’Xinongheidasui’ was the highest and increased 14.11% ～ 17.87%,55.74% ～ 58.89%,1.79% ～ 18.01% and 10.98% ～ 20.83% respectively compared with white wheat4.With the process of grain filling,the variation of Fe accumulation in grain and stem + leaf sheath of colored-grained wheat was different between vegetative organs and varieties.The Fe accumulation in leaf showed a trend of first upward then downward.The Fe accumulation in cob + glume showed the "N" type.The Zn accumulation in grains showed an upward trend,and the Zn accumulation in other vegetative organs showed a downward trend.Mn accumulation varies with vegetative organs.With the progress of the grain filling,the Cu accumulation of colored-grained wheat showed a trend of “N” type,and the Se accumulation of the grain showed an upward trend.At the later filling stage,the accumulation of Cu and Se in leaf,stem + sheath,and cob + glume both showed a downward trend.Variety,water,vegetative organs and their interactions and the interaction of three factors had significant or extremely significant effects on the accumulation of wheat Fe,Mn,Se and Cu in the maturity.In the maturity,the accumulation ratio of Zn,Cu and Se in colored-grain wheat grain was the largest,and the accumulation ratio of Mn was the largest in the leaf.Irrigation environments increased the accumulation and distribution ratio of Fe and Se in colored-grained wheat grains,while inhibited the accumulation and distribution ratio of Fe and Se in the stem + sheath.Irrigation environments significantly reduced the accumulation of cob + glume Mn accumulation,stem + sheath Zn accumulation,and grain Cu accumulation(p < 0.05).There were differences among varieties on the effects of Mn,Zn and Cu accumulation and accumulation distribution ratio on other vegetative nutritious organs.Based on the analysis of the content and accumulation of trace elements in wheat,it can be seen that the colored-grain wheat ’Xinongheidasui’ has the potential of high nutrition resources.