The examination of yield and process grain growth of four hybrid of grain corn in three deta of planting in the north of Khozestan

For the purpose to the examination of the different levels of planting time on the process of the growth of grain, yield and the yield parts of corn new hybrid, a test was performed in the center of safiabad agriculture investingations in summer of 2003. This investingation was performed in the form of pieced cretes in the mold of a coincidence desingh perfect block. Main factor in three ieveis of the date planting twenty- second tir, first mordad, eleventh mordad and secondary factor contained four mercantile hybrid sc.4-s-3393, sc.4-s-3261, sc.4-s-3282, sc.704. statistic accounts dispiayed, difference yield of grain is significant in the probability level 1%, for numerals and different levels of the planting time and also their mutual effect was significant in the level 5%. Extreme grain yield is achieved in the planting time of first mordad with medium 11310 kg.ha-1 and its least in the planting time of twenty second tir with medium 8065 kg.ha-1 . hybrid sc.4-s-3393 appropriated extreme with medium grain yield 10490 kg.ha-1 and hybrid sc.4-s-3261 appropriated least grain yield with medium grain yield 9263 kg.ha-1. from the viewpoint of mutual effect, extreme grain yield contained 12420 kg.ha-1 relative to number sc.4-s-3393 in first mordad and its least with yield 6689 kg.ha-1 relation to sc.4-s-3261 in the planting time twenty second tir. Significant difference isn,t observed between subject numerals, the planting time and their mutual effect from the viewpoint of biological yield qualities, numbers grain in a corn and the depth of grain. In between different levels of the planting time is not observed significiant difference from the viewpoint of the qualities of number of grain row in corn, number of grain in the row, the diagonal of grain and corn,s length. But the planting time cares had significant difference in the level 5% from the viewpohnt of the qualities of diagonal of corn, corn cob percent, the height of bush and corn. Also the qualities of the weight of grain and the harvest index in between the planting time had significant difference in the probability levels 1%. in between numorals before is not observed significiant effect from the viewpoint of the number of grain in row, the length and diagonal of corn, corncob percent and the diagonal of grain, but difference numeral was significient in relative to the qualities of the weight of ears and the height of corn in the probability level 1% and in case of the qualities of the number of grain row, the diagonal of grain, and the height of bush and theharvest index. In between the mutual effect of the planting time and the numerals, the qualities: The weight of cobs, the diagonal of corn, the height of corn, and cob percent did not present but the mutual effect in case of the qualities of the numbers of grain in the row in the level 1% and in case of the qualities of the row numbers, the length of corn, the diagonal of grain, the height of bush and the harvestin index in the probability levels was significiant. Coeficients of correlation between the yield of grain and other qualities presented that there are extreme rate correlation between the yield of grain and the biological yield and the harvest index and also there was positive and significiant correlation are between the yield of grain and the speed of filling grain. Keywords: Planting date, Seed growing, Cultivars, Maize