Effect of planting date and method on ear yield, water use efficiency and some phenological characteristicsof sweet corn in Yasouj

To study the effect of plantingdate and method on ear yield, water use efficiency and some phenological characteristics of sweet corn, an experiment was carried out as split plot based on randomize complete blocks design with three replications in research farm of the Faculty of Agriculture, Azad University of Yasouj, Iran, in 2016. The main factor of the experiment included planting date in five levels (4 and 19 May, 4 and 19 June and5 July) and the sub factor wasplanting method in three levels including seed cultivation, 15-day seedling (three leaf stage) and 20-day seedling (four leaf stage) cultivation.The results showed that the effect of planting date and method interaction on ear yield and water use efficiencywas significant. Mean comparison of data indicated that 15-day seedlingcultivatedat May 4th had the highestcanned grain yield (16 t.ha-1) and 20-day seedlingat July 5thhad the lowest ear yield (8.24 t.ha-1). The highest water use efficiency (2.93 kg.m-3) was also obtained from 15-day seedling cultivation at May 4th, which was 66% higher than the 20-day seedling atJuly 5th. The effects of planting date and method on vegetative period and days from planting to harvest were significant. The vegetative period decreased with delay in planting date, so that the highest vegetative growth period was obtained in the planting date of May 4thand the lowest in the July 5th.Also, the duration of vegetative period in the seedling cultivation method was less than the seed cultivation method, so that the seed cultivation with growth period of 87.4 days and 20-day seedling cultivation with77.1 days had the highest and lowest growth period, respectively. In addition, the seedlings cultivation method increased grain sugar content.In total, the results of this research showed that the application of seedling cultivation method can accelerate the maturity of the plant, and therefore, when the plant may be exposed tounfavorable weather conditions, the growth period can be reduced by the application of seedling cultivation.