Nitrogen rate and plant density effects on yield and late-season leaf senescence of cotton raised on a saline field

作者：Dong, Hezhong^*; Li, Weijiang; Eneji, A. Egrinya; Zhang, Dongmei

来源：Field Crops Research, 2012, 126: 137-144.

DOI：10.1016/j.fcr.2011.10.005

• Bt cotton
• Plant density
• Nitrogen fertilization rate
• Lint yield
• Leaf senescence
• Cry1Ac expression

Plant density and nitrogen fertilization are two important practices for field-grown cotton (Gossypium hirsutum L). The objective of this study was to investigate the effects of plant density and N fertilization rate, especially their interactions, on yield, yield components, late-season leaf senescence and Cry1Ac expression in Bt (Bacillus thuringiensis) cotton under salinity conditions. To achieve this goal, we conducted a three-year experiment with a high-yielding Bt cotton cultivar (SCRC 28) in a moderately saline (ECe = 11 dS/m) field, using a split-plot design in the Yellow River Delta of China. The main plots were assigned to low, medium and high plant densities (3.0, 5.25 and 7.5 plants/m(2)), while low, moderate and high nitrogen rates (120, 225 and 300 kg N/ha) were assigned to the subplots. Biological yield, lint yield, yield components, harvest index, boll load, Cry1Ac expression and leaf senescence were significantly affected by plant density and N rate. Lint yield was also affected by plant density x N rate interaction. Increased plant density or N rate enhanced biological yield, but reduced harvest index. Considerably high lint yield (1604 kg/ha) was achieved only with a high dose of N fertilizer under low plant density, but comparable yields (1693 and 1643 kg/ha) were achieved with moderate and low N rate under medium and high plant density. Increased plant density and N rate reduced boll load, which had highly significant negative correlation with late-season leaf photosynthesis (r= -0.928) and significant correlation with Cry1Ac protein concentration (r= 0.8131). Leaf senescence was delayed by increasing plant density and N rate mainly due to reduced boll load and a combination of reduced boll load and nutritional effect. Medium plant density with moderate N rate or high plant density with low N rate would enhance cotton yield and moderate Cry1Ac expression at reduced cost in the Yellow River Delta of China and other areas with similar ecologies.

• 出版日期2012-2-14
• 单位山东省农业科学院