The Effect of Sowing Date and Some Growth Physiological Index on Grain Yield in Three Maize Hybrids in Southeastern Iran

摘要

One of the most important objectives in farming systems is to minimize the risk probability as well as maximizing the production level. This study, using a spilt plot experiment based on RCBD with three replications, aims to study the effect of sowingdate on yield and growth physiological index of maize cultivars. It was conducted in 2005/06 at the research farm of the Faculty of Agriculture in University of Zabol, Sistan-Baluchistan province, Southeastern Iran. Experiment factors were: Three maizehybrid cultivars (Namely, S.C 108, S.C 604 and S.C704) that were subplot and sowing dates (5 July, 20 July, 5 August and 20 August) that were main plots. Results indicated that sowing dates have significant effects on yield and physiological index in maize cultivars. They Maize hybrids have different response to these parameters. The highest grain yield and harvest index was obtained from 5 August. The first sowing date (5 July) was associated with a decrease in Leaf Area Index (LAI). Leaf Area Index Duration (LAID) and Crop Growth Rate (CGR). As a result, S.C 704 cultivar has the highest of CGR, LAI, LAID and grain yield (11.5 t ha~(-1)), On the contrary, S.C 108 cultivar has the lowest of the CGR, LAI, LAID and grain yield (6.4t ha~(-1)). Consequently, it can suggest that S.C 704 cultivar should be applied and the sowing date should be adjusted to 5 August in conditions of Sistan. This could be contributed to optimum temperature and decrease wind speed during the flowering, grain formation and filling stage.