Epsilon Archive for Student Projects

Abstract

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. The dry weight of the collected ears was quantified. In addition, ear length, number of spikelets per spike, number of grains per spikelet and the kernel position in the spikelet was determined on the samples from the third cut.

The study shows that it is possible to classify the different winter wheat varieties, based on the ability to compensate for the different yield components. Five different ways to compensate were separated among the seven varieties compared here.

1. The number of ears

2. The number of ears and kernel weight

3. The number of ears and number of kernels

4. The number of spikelets per spike

5. The number of kernels per spikelet

In the two northernmost experimental sites, there were significant differences in the number of plants and ears, and the conditions for a high yield seemed to be better for the cultivars with a high ability to produce ears. In the two southernmost sites, there were no significant differences in ear density between cultivars. This implies that the conditions for a high yield were better for the varieties where the most important yield component is the number of kernels per ear rather than the number of ears. Varietal differences appear to be stable as the yield components of the cultivars were not influenced significantly by changes in sowing density or date of sowing.