Effect of Planting Date and Sowing Methods on Ear Yield, Water Use Efficiency and Some Physiological Characteristics of Sweet Corn

In order to investigate the effect of planting date and sowing method on ear yield, water use efficiency and some physiological characteristics of sweet corn, an experiment was carried out as a split plot based on a randomized complete block design with three replications in Yasouj, south-west of Iran. Planting date consisted of five levels (4 May, 19 May, 4 June, 19 June, 5 July) and considered as the main plots and three levels of planting methods (seed cultivation, transplanting cultivation [15-days after planting (3-leaf stage)] and [20-days after planting (4-leaf stage)] were assigned to the sub-plots. Planting date and sowing method interaction effects were significant on ear yield and water use efficiency. Transplanting at 3-leaf stage on the 4th of May had the maximum ear yield (16000 kg ha-1) and at 4-leaf stage on the 5th of July had the minimum ear yield (8000 kg ha-1). The highest water use efficiency (2.93 kg m-3) was obtained by transplanting on the 4th of May and 3-leaf stage, which was 66% higher than the water use efficiency of those transplanted on the 5th of July and at 4-leaf stage. The effects of planting date and sowing method were significant on grain protein content. With a delayed planting, the grain protein content was increased so that the maximum of grain protein content (8.7%) was obtained in the 5th of July and the lowest (8%) in the 4th of May transplanting. The grain protein concentration of the transplanting treatments was less than the grain protein of the seed cultivation treatment. The high temperature stress experienced by sowing at the 19th of May until the 19th of June decreased the grain sugar content. Transplanting cultivation led to increase in the amount of total sugar compared to seed cultivation. The best treatment in this study was found to be transplanting at 3-leaf stage on the 4th of May.