ویژگی‌های کمی و کیفی عملکرد دانه سورگوم تحت ‌تاثیر نیتروژن و تراکم بوته

The effect of N levels and planting densities on quantitative and qualitative characteristics of grain yield in grain sorghum (cv. Kimia) was studied in summer 1998 at Kushkak Agricultural Research Station, Shiraz University. The experiment was a spilt plot with 4 replications in which 4 levels of planting densities (7.7, 10, 15.4, 20 seeds m-2) were applied as main plots and 4 levels of N (0, 40, 80, 120 Kg N ha-1) as subplots. N application rates up to 120 kg N ha-1 increased grain yield (7240 kg ha-1), but due to increased planting density (5336 kg ha-1) the highest yield obtained from 15 seeds m-2. Interaction of N and planting density was also significant. Application of 80 kg N ha-1 and highest planting density produced 8702 kg ha-1 of grain. Different grain yields in different levels of N and planting densities were due to increased number of grains per basic branches of panicle and increased number of panicle per m-2. The trend of variation of crop growth rates (CGR) was similar to the trend of grain yield. Nitrogen application increased grain protein contents but planting density had no significant effect on grain protein. Phenolic compounds (tannins) decreased with increasing N application and with decreasing planting density. A negative correlation was observed between increased N content and increased phenolic compounds.