Effect of Planting Date and Cultivar on Growth Stages, Morphological Traits and Growth Indices of Corn in Karaj City

To evaluate the effect of planting date on the morphological traits, growth indices and seed corn yield of three varieties, an experiment was carried out in the research farm of University of Tehran in Karaj city in 2019.

The experiment was conducted as a split-plot design based on randomized complete blocks with four replications. In this experiment, planting date in 3 levels (May 24, June 21, and July 18) was considered as main plots and variety (early KSC400, medium-early KSC647, and late KSC704) as sub plots.

The results showed the highest yield is related to the second planting date (11.98 ton/Kg-1), and the longest period until the appearance of the the tassel was belonged to the first planting date (63.7 days).
The third (129/7 days), the second (122/3 days) and first planting date (113/3 days) had the longest period of physiological maturity, respectively. Also, KSC704 had the highest plant height and stem diameter, and KSC647 had the highest number of leaves. Also, the maximum leaf area, the growth rate of crop in the flowering stage was related to the cultivar KSC704 on the second and third planting date, respectively, and the maximum relative growth rate and the net absorption rate in the first vegetative stages were related to the cultivar KSC704 on the third planting date and the second planting date.

Overall, the second planting date and KSC704 variety are suggested as the suitable date and variety for Karaj city.