The objective of this study was to assess genotype by environment interaction for seed yield in rapeseed cultivars grown in West Poland by the additive main effects and multiplicative interaction model. The study comprised 25 rapeseed genotypes (15 F₁ CMS ogura hybrids, their parental lines and two varieties: Californium and Hercules F₁), analyzed in five localities through field trials arranged in a randomized complete block design, with four replicates. Seed yield of the tested genotypes varied from 15.9 to 80.99 dt/ha throughout the five environments/localities, with an average of 39.69 dt/ha. In the variance analysis, 69.82 % of the total yield variation was explained by environment, 13.67 % by differences between genotypes, and 8.15 % by genotype by environment interaction. Seed yield is highly influenced by environmental factors. Due to high influence of the environment on yield high adaptability of the genome is required.

Brassica napus (L.), winter oilseed rape (WOSR) or canola, is one of the most important oilseed crop species of the moderate climate zone. Improving the seed quality and yield makes the main target in breeding programs worldwide. In this study, we examined the genotype-by-environment (G×E) interaction with respect to six seed traits among 25 WOSR genotypes. The plant material included the registered canola cultivars, our newly developed mutant breeding lines and the Ogura F1 hybrids and their parental components, in addition to our domestic breeding lines including two semi-resynthesized (semi-RS) lines. The 25 genotypes were examined in field trials at two locations, in three growing seasons. Seed oil and protein content, total glucosinolates (GLS) content in seed meal and C18 unsaturated fatty acid (oleic, linoleic and linolenic) composition in seed oil were examined. The additive main effects and multiplicative interaction (AMMI) analyses revealed significant effects of both, genotype (G) and environment (E) as well as the G×E interaction regarding the analyzed seed traits. In our study, two Ogura F1 hybrids, a CMS line and a new high oleic mutant breeding line revealed high stability and good average values for most of the analyzed seed traits, thus making a valuable source of starting materials for further improvement.

Far too often, phenotypic divergence has been misinterpreted as genetic divergence, and based on phenotypic divergence, genetic divergence has been indicated. We have attempted to disprove this statement and call for the differentiation of phenotypic and genotypic variation.

Selection of parental lines is important in plant breeding programmes. Marker-assisted selection is an alternative to classical selection methods, which are expensive and time consuming. Marker-assisted selection aims to find molecular markers that are linked to genes that determine quantitative traits of interest. Classical statistical methods require particular assumptions to be fulfilled, which is difficult to check if the analyses are performed automatically. In this article, we present a heuristic method to find interesting markers for quantitative traits. This method includes various strategies that depend on what makes a genotype interesting to a plant breeder. This approach was applied to eighteen parental lines of winter oilseed rape F₁ CMS ogura hybrids with observation of 597 markers. The traits of interest were seed yield and alkenyl glucosinolate content. Fifty-seven markers were selected for further study. The most prominent marker was OPY 02~1830. Marker-assisted selection is the first step of analysis, which can then be followed up by a more formal statistical analysis for a smaller set of interesting markers.