Corn Yield Response to Nitrogen Rate and Timing in Sandy Irrigated Soils
In order to evaluate genetic diversity of grain yield, nitrogen uptake efficiency and selecting superior varieties, a factorial experiment with the based on Complete Blocks design with four replications was carried out in Saatlo agricultural research station, six corn genotypes (single cross 301,370,540,700,701 and Back cross) and three amounts of nitrogen fertilizer (urea) (27 as a control, 110 and 193 kg/hectare) established as second factors. Results of analysis of variance showed that there was high diversity in most traits with reducing of nitrogen levels. Between different levels of nitrogen fertilizer and genotype for traits such as ear diameter, row number per ear, grain per row, flag leaf area, stem diameter, plant height, grain yield, total dry matter and harvest index were significant difference (p 0.01). Grain yield of Single cross 700 and 701 was more than other genotypes. Maximum and Minimum agronomic nitrogen use efficiency were seen in 110 kg nitrogen per hectare for single cross 540 and 193 kg nitrogen per hectare for single cross 701, respectively. The highest and lowest apparent nitrogen use recovery was obtained in 110 kg nitrogen per hectare for single cross 370 and 110 kg nitrogen per hectare for single cross 540, respectively. Maximum physiological nitrogen use efficiency had in 110 kg nitrogen per hectare for single cross 540 and minimum value was seen in 193 kg nitrogen per hectare for single cross 701.