Seed density- and seeding time examinations have been carried out on salty meadow chernozem soil, in four growing seasons (2003/2004, 2004/2005, 2005/2006, 2006/2007), with four winter wheat species (GK Garaboly, GK Kalász, GK Petur, GK Holló), in four replications, on 10 m2 plots (randomized block design), after oilseed rape as preceding crop. The same agro-technological measures and crop protection applications have been applied on the plots, with different seeding time. Seeding took place in mid-October and early November, with 300 and 500 seed/m2 seed densities.

It can be determined that sowing time has a significant effect on the number of shoots, ears, spikelets of winter wheat per area unit, but the effect of sowing time on the number of grain and grain weight could not be proved statistically. On the basis of the four examined years and four genotypes it can be determined that the early November sowing time is slightly more favourable than mid-October at the Szeged production site. Nevertheless, GK Kalász and GK Petur varieties and years 2003/2004 and 2005/2006 were different. In our experiments, due to the different seed number, the number of shoot-, ears-, and spikelets per area unit have shown significant difference. The reduction of seed density has decreased the majority of yield components and yield, too, but the good adaptability of winter wheat made it possible for lower seed density plant stand to perform better tillering; therefore, the reduction of measured yield components is not in proportion to the change in sowing seed quantity. In winter wheat production, seed density and sowing time are close correlative agrotechnical factors that should be evaluated simultaneously and the effect of year and variety must be taken into consideration, too.

Keywords: winter wheat, yield components, sowing date, seeding rate