Grain yield and protein component responses to plant density and nitrogen application strategies in winter wheat (Tritcum aestivum L.)

The effects of basic seedling and nitrogen application strategies on grain yield and protein components in winter wheat were studied using cultivar Zhongmai 175 in a randomized block design with two factors or single factor. The experiment was carried out in the experimental farm of the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences. The results showed that plant height, spike length, the number of grains per spike and grain yield were significantly different among the treatments of the basic seedling and nitrogen application. The spike length and number of grains per spike were positively correlated (r=0.884**). In the case of slightly late sowing, the highest grain yield was obtained in the treatment of basic seedling 375×104/ha and nitrogen application 300 kg/ha. The number of grains per spike and the thousand-grain weight were reduced with the increase of the basic seedling. The grain yield was highest when the basic seedling was 375×104/ha. But there was no significant difference in the grain yield between the basic seedling 300×104/ha and 450×104/ha, so the basic seedling could be 300–450×104/ ha if sowing is slightly late, according to actual sowing date and soil fertility. The grain yield increased with nitrogen from 150 to 300 kg/ha, and was significantly different among the treatments. The glutelin and total protein content increased with the basic seedling reducing from 450–225×104/ha, and they were significantly different among the treatments. The protein components and the total protein content increased with the increase of applied nitrogen, and they were significantly different (p0.01), except glutelin, among the nitrogen treatments. It was the best in spike length, the number of grains per spike and grain yield in the treatment of topdressing 50% of total nitrogen application at 5 leaf stage, and they were significantly different among the treatments. The total protein content was highest in the treatment of topdressing 50% of total nitrogen application at anthesis, and was significantly different from the treatment of topdressing 50% of total nitrogen application at 2 leaf stage.