Effect of Plant Density on Grain Yield of Wheat Genotypes with Different Tillering Capacity in Dryland Conditions

In order to evaluate the effect of density on tillering capacity of wheat genotypes, this experiment was conducted with factorial design based on RCBD in three replications and two years in Maragheh Dryland Agriculture Research Station. The treatments were four seed rates 250, 350, 450 and 550 seed/m2 and six advanced wheat genotypes: V1=Azar2, V2=10 Ghazaghestan 98-99 and V3=Kiraj/87-zhong291 with high, medium and low tillering capacity, respectively and V4=885K1.1//1D13. 1/MLT/3/YE2453, V5=Gun91/Karl andV6=Fenkang15/sefid with low, medium and high thousand kernel weight (TKW), respectively. Combined analysis of results showed that genotype effect was significant for plant height, green cover percentage at flowering stage, spike length, seeds/ spike, TKW, days to maturity, productivity degree, biological yield, grain yield (p < %1) and on total tiller number, number of fertile tillers, days to flowering (p < %5). Seed rate effect was significant on green cover percentage at flowering stage, spike length, spikes/m2, seeds/ spike, days to flowering, days to maturity, biological yield and grain yield (p < %1). Genotype seed rate interaction was not significant for any of the traits. Based on these results, as no significant difference in different seed rates was observed for yield of genotypes V1, V4 and V5, therefore 250 seeds/m2 can be recommended for these genotypes. Similarly in genotypes V2, V3 and V6 seed rate of 250 seeds/m2 produced significantly lower yield compared to the other seed rates, thus 350 seeds/m2 can be recommended for these genotypes. Among yield components, only spikes/m2 and seeds/spike were affected by seed rate. The highest spikes/m2 belonged to 550 seeds/m2 and lowest seeds/spike were obtained from 250 seeds/m2. Results of correlations were similar to this inverse relationship.