The effect of seed rate on grain yield and its components of wheat cultivars in rain fed Conditions

In order to investigate the effect of five seed density100,200,300,400(and 500 grain m 2) on yield and yield components of wheat digits under rainfed conditions. A factorial experiment based on in a randomized complete block design with three replications was conducted at agricultural research station of Khorramabad in 200 cropping season. The results showed that there was significant difference among cultivars for grain yield, but among the seed densities and for interaction effect of cultivars × seed densities on grain yield no significant differences were observed. Chamran cultivar had the highest grain yield(5895 kg ha-1) among the cultivars. The 400 seed m-2 had the highest grain yield(5449 kg ha-1) and Chamran cultivar in 400 seed m-2 treatment had the highest grain yield(6335 kg ha 1). The correlation between grain yield and biological yield, straw yield and number of spike m-2 was positive and significant, but correlation between grain yield and test weight and thousand kernel weight was negative and significant. The results of path analysis indicated that three characteristics including number of spike m-2, number of grain per spike and thousand kernel weight were main yield components for grain yield. The correlation analysis showed that the number of spike m-2(r=1.55**) and number of grain per spike(r=0.99**) had positive and the highest direct effect on grain yield.