Effects of low seedling density cultivation on photosynthetic characteristics and grain yield and water use efficiency of dryland winter wheat

In order to evaluate effects of low seedling density cultivation on photosynthetic characteristics and grain yield and water use efficiency of dryland winter wheat,the photosynthetic rate and photosynthesis yield and relative electron transport rate of winter wheat flag leaves,light transmission rate of population,grain yield and water use efficiency were measured and analyzed with 4 winter wheat varieties under lower density in field experiments.The results showed that,in the period from anthesis to dough stage,photosynthetic rate and photosynthesis yield and relative electron transport rate of flag leaves,light transmission rate of population were improved by low seeding density cultivation,change trend of them among different wheat varieties were the same.Compared with plant density of 150×104 plants/hm2,photosynthesis attenuation rate of traditional plant density of 450×104 plants/hm2 increased by 25.2～43.5 percent point,photosynthesis yield and relative electron transport rate of them decreased 2.95%～20.68% and 10.66%～18.32%,respectively,and the proportion of the reception of photosynthesis active radiation increased upper the layer of flag leaf,and decreased the proportion received lower the layer of flag leaf.These suggested that low seedling density cultivation have great advantages in photosynthesis ability,electron transfer,and light energy transform at late growth stage.The relative low planting density(300～375×104 plants/hm2) will benefit the construction of population structure,which increases grain yield and water use efficiency of dryland winter wheat to a much higher level,and the grain yield and water use efficiency were respectively increased by 12.55% and 14.48% compared to that of traditional plant density of 450×104 plants/hm2.