The Effect of Planting Date on Agronomic and Physiolocal Characteristics of Maize Hybrids in Different Groups in Jiroft Region of Kerman Province

In order to investigate the effect of planting date on agronomic and physiolocal characteristics of maize hybrids in different groups in Jiroft region of Kerman province, an experiment as a split plot in the randomized complete block design with three replications in the city of Jiroft in the crop year 2017-2018 was conducted. Experimental factors were included planting date as the main factor at three levels of July 27, August 3 and August 10 and different hybrids as a secondary factor at 10 levels of early, late and medium maturing hybrids (701, 703, 705, 706, 707, 201, 260, 400, 370 and 704 as controls). There was a significant difference between the studied hybrids in terms of agronomic and physiological characteristics. The highest number of rows per ear was obtained in hybrid 706 and the highest number of seeds per row was obtained in hybrid 707. Delaying in planting was associated by of increasing stem diameter and biological yield and decreasing of plant height, ear length, number of rows per ear, seed yield, harvest index, GDD to physiological maturity and spad. By Delaing in planting, seed protein percent and proline accumulation increased. The most seed yield was obtained on July 17 in hybrid 260 (18.24 t.ha-1), August 3 in hybrid 210 (17.46 t.ha-1) and August 10 in hybrids 370 and 201 (17.4 and 17.28 t.ha-1). It seems that the delayed planting date due to exposure to unfavorable temperatures during tillering, pollination and granulation, as well as the reduction of the growing period was decreased yield and yield components.