Multi-environmental evaluation of winter oilseed rape genotypic performance using mixed models

The production of winter oilseed rape (WOSR) (Brassica napus) together with increasing seed yields per hectare is one of the strategies for breeding the genetic base of oilseed rape genotypes adapted to different environments. The main objective of this study was to evaluate the genotypic performance of 25 winter oilseed rape genotypes using mixed models. The plant material was examined in five locations in Poland. Field trials were carried out in a randomized complete block design with four replicates. The REML/BLUP was used to estimate genetic parameters. Selection of genotypes was made on the basis of genetic values by the harmonic mean of relative performance these parameters. The mean heritability for genotype had an average value at a high accuracy of selection, while additionally it facilitated selection of agronomically superior individuals. Three restorer lines PN18, PN17 and PN21, CMS ogura line PN64 as well as hybrids PN66 x PN21 and PN64 x PN21 characterized good adaptability and stability of seed yield. There were similarities among the statistics ((mu) over cap + (g) over cap), adaptability and stability of genetic values in the discrimination of the most productive genotypes by best linear unbiased predictor analysis. Mixed models can be recommended as a potential selection method for the inclusion of new plant material in different oilseed rape breeding programs aimed at developing new WOSR cultivars.