استفاده از گزينش شاخصي در يك جمعيت F3 برنج

Interaction Effects of Weeds and Nitrogen on Growth And Yield of Dryland Wheat (Triticum aestivum L.) and Soil Organic Carbon

Inorder to evaluate the interaction effects of weeds and nitrogen ongrowth andyield uf Jryland wheat. an experiment was conducted at the research station of the college of agriculture, Shiraz University at Bajgah in 2005. Theexperimental design was split plot with randomized complete hlock arrangement in which weedy and weed free lTealments were main factors, while three levels of nitrogen (0, 40, and 80 kg N he") constiteuted the sub factors. Under weedy conditions, wheat grain yield decreased significantly (from 1282 to729kg/ha). Among yield components, number of seeds perspike decreased significantly. Thenumber of spikes perm2 was reduced but this reduction was not significant. Results indicated that with increase in nitrogen level, wheat yield increased significantly (from 661.5 to 1370). Under weedy conditions, harvest index decreased. Harvest index increased by increase in nitrogen rate but there was no significant difference observed between 40 and 8Q kg nitrogen ha". Treetments. Results indicated that in the respective weedy and weed free conditions, maximum rateof soil organic carbon was obtained from the additions of 40 and KO kg of N ha-I , respectively. Under weedy conditions, soil organic carbon was observed to increased significantly.