The effect of seeding rate on wheat cultivars performance under salinity stress

Effects of five seeding rates (350, 425, 500, 575 and 650 seeds per m2) on four wheat cultivars (Kavir, Mahdavi, Shiraz and Roshan) were studied under salinity stress, during 2000-2001 crop seasons in Roodasht Agricultural Research Station, Esfahan. A factorial experiment based on randomized complete block design with three replications was used. Plants were irrigated with saline water (with EC=12 ds/m) throughout the growing season. Two years combined analysis of variance showed that seeding rate had significant effect on grain yield, number of spikes per m2, thousand kernel weights, biomass and harvest index. However, the effects on plant height and number of grains per spike were not significant. Cultivars were significantly different in all studied traits. Increase in seed rate up to 500 seeds per m2 caused increase in grain yield, but seed rates more than 500 seeds per m2 did not cause more increase in grain yield. Therefore, 500 seeds per m2 that produced an average of 2890 kg/ha of grain yield, was the suitable seed rate under the conditions of this experiment. Increase in seed rate also caused increase in number of spikes per m2 and biomass, but decrease in thousand kernel weight and harvest index. Throughout the studied seed rate range, there was linear relationship between seed rate and grain yield.