Study of the possibility of using Tropical and Sub-tropical maize hybrids in Temperate Regions of Iran

In order to study the adaptation of Tropical and Sub-tropical hybrids in temperate conditions of Iran, two groups of tropical and subtropical maize germplasms, each including 18 hybrids and two adapted commercial hybrids, KSC 647(medium maturity) and KSC 704 (late maturity) were evaluated in two separate experiments using randomized complete block design with three replications, in 4 locations of Iran (Karaj, Gorgan, Darab and Dezful), in 2002 cropping season. In general, Sub-tropical hybrids performed better adaptation in Darab(28º and 46', latitude)and Dezful (32º and 24', latitude), comparing to Tropical hybrids,due mainly to similarity of latitude to the origin of these germplasm. The possibility of using these germplasm in Karaj and Gorgan is low, due mainly to lower yield of these hybrids, which could be due to longer ASI and delayed flowering. In Darab and Dezful, Sub-tropical hybrids performed successful in comparison with local adapted hybrids, indicating that these germplsm can be used as a new genetic resources for extraction of distinct inbred lines. Desirable performance of sub-tropical germplasm, especially in Darab, implies that they would be more promising for increasing the efficiency of hybrid maize breeding program for these regions.