Determination of the Suitable Planting Date for New Early Maturity Maize Hybrids in Second Cropping in Temprate Regions in Fars Province

This study was carried out to evaluate effects of four planting dates (22 June, 01 July, 11 July, 21 July) on four new maize hybrids (KSC260, KSC302, KSC400, KSC500) and KSC704 in Zarghan of Fars Province in three growing seasons (2005-2007). Split plot arrangements in randomized complete block design with four replications was used. Results showed that planting date had significant effect on grain yield and yield components. Delay in planting date decreased the grain yield but first and second planting date had no significant difference. The effect of hybrids was significant on all of the measured characteristics. KSC704 had the highest grain yield in first planting date (13.53 t/h with 14% moisture). KSC260 had greater grain yield (12.03 t/h with 14% moisture) in second planting date. Grain moisture of KSC260 and KSC704 was the least and the highest moisture content, respectively. The highest average grain yield over three years and four planting dates obtained from KSC260 (Fajr) and KSC400 (Dehghan) with 10.41 ton/ha (with 14% moisture). Cold in late growing season affected KSC704 hybrid in all planting dates except first planting date, however, cold affected KSC260 and KSC400 hybrids only in fourth planting date. Therefore, KSC260 and SC400 hybrids are recommended for second cropping in temprate regions in Fars province. These two hybrids need 115-120 days to reach physiological maturity .