Wheat yield depends on the number of ears per m2, the number of kernels per ear and the kernel weight. By knowing the ability of different cultivars to compensate for the different yield components and knowing which yield component that is the most important for the final yield, the farmer can match the cultivar and management to the location. The objective of the study was to investigate how the yield components of winter wheat vary depending on genotype, environment, sowing density and date of sowing.Seven varieties were grown in four locations in Sweden with three different sowing densities and with an early and a late sowing date. On each experimental site, the surviving plants after winter were counted, as well as the number of shoots at early and late spring and the number of ears. Ten ears from each site were cut at three different occasions, starting from the time of blooming, with 200 day degrees between each cut.