Effects of Planting Date and Density of Female Parent B73 on Hybrid Seed Production of KSC704 in Fars Province

An experiment was conducted to determine a suitable planting date and density for B73 line, using a randomized complete block design (RCBD) in split plot arrangement with four replications in Zarghan for two years (2002-2003). Five planting dates (5 May, 20 May, 4 June, 19 June and 4 July) were assigned to main plots and three different spaces between plants in maternal rows consisted of 15, 18 and 21 cm were considered as sub plots. Yield and yield components were assessed in each plot. Combined analysis of variance showed the significant effect of planting dates on yield and yield components, such as kernel number/ear row, row number/ear, 1000 kernel weight and kernel depth. The best planting date was 4 June that produced 4.604 tha-1 of seeds with 14% moisture. Results showed that the plant density of maternal line had significant effect on yield (P=0.01), and the highest yield was obtained from the highest density of maternal line. Intreraction of planting date and density was not significant on seed yield, but the highest seed yield was obtained from those with 15 cm plant spacing on maternal rows on 4 June planting date. B73 inbred line rows that were closed to MO17 inbred line rows had higher seed setting and more seed yield than the others. Maize Rough Dwarf Virus epidemic occurred in Zarghan in 2003, affected the seed yield of plots planted in 5 May and 20 May so that the first planting date (5 May) which had the highest yield in 2002, produced the lowest yield in 2003