عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In order to study the seed quality indicators of hybrid maize seed at development and maturity stages and planning harvest time, an experiment was conducted in a complete randomized design, with three replications and five sowing dates (T1 = 22 April, T2 = 6 May, T3 = 21 May, T4 = 12 June and T5 = 29 June) in Karaj, Iran. Phenology and morphology related traits were evaluated during plant and seed growth. After pollination, Sampling from ears was done in weekly scale from female rows (B73 Inbred line). The harvested seeds were dried in open air condition, and then laboratory tests were done. Depends on the sowing date and temperature, seed filling rate (SFR) and periods (SFD) were significantly different. Physiological maturity or maximum normal seeding occurred around 47-68 days after flowering (DAF), when the seed moisture varied in a range of 40-54 % and mass maturity (maximum seed weight) occurred at 47-86 DAF, when the seed moisture ranges about 40-43%. But black layer in seed formed when the seed moisture was about 32-35%. So, maximum seed quality occurred earlier to mass maturity. While the black layer formation happened as the final stage of development. The more the delay in sowing dates, the higher the seed moisture for occurring mass and physiological maturity. Depends on the sowing date and appropriate drying, harvesting the seed at higher level of moisture was possible. It is more likely that seed moisture prepare a more suitable indicator for detecting the changes trend in mass and physiological maturity, in compared with DAF and GDD.