The Effect of Sowing Date and Plant Density on Morphology, Phenology and Yield Variables of Maize Hybrids in Bonab Region

In order to investigate the effect of sowing date and plant density on morphology, phenology and yield variables of 704, 540 and 500 maize hybrids, a factorial experiment was carried out based on complete randomized block design with four replications. In this research, row space was fixed at 75cm and inter row spacing was 12, 15 and 18cm that create 111500, 89000 and 74000 plants per hectare, respectively. In this study, the highest number of kernel rows per ear, with 18. rows, was obtained by hybrid 500. Whereas, the highest number of kernels per row, with 24.4 kernels, was produced by hybrid 704. But, among studied hybrids, the number of kernel per ear was not significant. The results also showed that the highest forage yield, with 48.1 ton per hectare, was obtained by hybrid 704 and hybrids 540 and 500 with 42.6 and 40.8 ton forage yield per hectare ranked next, respectively. High performance of hybrid 704 depends on its high biomass production so that the dry weight of hybrid 704 was 118.9 gram per plant that had significantly differences compared to other hybrids. With increasing of plant density, forage yield per plant was decreased significantly and forage yield per unit area was increased. The highest forage yield per unit area, with 46.3 ton per hectare, was acquired from 12cm row spacing. The study of phonological traits demonstrated that in Bonab region only hybrid 500 could reach to maturity stage (dough stage) for harvest. With respect to high quality of maize forage for silage at dough stage, the hybrid 500 for is suitable and if the purpose is grazing, sown of hybrid 704 with highest density is recommended.