OPRIATE SEEDING DEPTH FOR BREAD WHEAT GENOTYPES IN COLD DRYLANDS AREA OF MARAGHEH

Conservation tillage practices and proper seeding depth of wheat for early emergence before the first effective rainfall are very important in dryland cold regions. An experiment was conducted during 2001-2004 cropping seasons at the Dryland Agricultural Research Station, located in the northwest of Iran. The main objective of this study was to find the optimal seeding depth for wheat production in dryland. The treatments were, three wheat genotypes (Azer 2, Ogosta/ Sefid and Fenkang15/Sefid) as the main plot and three seeding depth (2-4, 4-6 and 6-8 cm) as subplots in strip plot design with three replications. Data were analyzed by the analysis of variance method. When the F-test indicated statistical significance at the 1% level, means were compared by the Duncan, s new multiple range test. Results showed that increase in seeding depth decreased number of heads per square meter, kernel size, biomass and grain yield significantly. The highest grain yield was obtained at 4-6 cm seeding depth in Azer 2 with 2580 kgha-1. Genotypes differed significantly in grain yield. Fenkang15/Sefid with 2149 kgha-1 had the highest grain yield. The number of heads per m2 had the main effect on yield increase. The highest number of heads per m2 (338 head per square meter) belonged to 2-4 cm seeding depth .