Stability analysis of tuber yield using unbalanced data from potato variety trials

摘要

Potatoes are grown in a wide region and in different environments unlike other crops, so it is known as one of the most spread world crops. In many agriculture areas around the world new genotypes are included in many multi-locational experiments at a large number of locations and years to determine the level and the stability of yields. However, there are a lot of problems with this traditional approach mostly due to the large number of genotypes that require consistent checking of every genotype at numerous locations and years. Multi-locational experiments require a lot of time and financial resources, and the possibility of error is greatly increased. In the present study we used the REML/BLUP method to predict tuber yield in an unbalanced set consisting of 54 potato genotypes investigated over twelve years at three locations. The data were subjected to stability analysis using the AMMI model based on estimated values. The analysis of variance showed that the greatest effect can be attributed to the environment (E), then to their interaction (G×E) and least to the genotype. The first two multiplicative interaction components explained 85.4% of the interaction sum of squares. AMMI analysis enabled the identification of stable and productive genotypes as well as genotypes adapted to specific environments and clearly separated the three locations as mega-environments. The genotype selection index (GSI), due to its nature of combining the assessments of stability measure and yield rank, provided more useful information for selection and recommendation. The results of this study indicate the superiority of the prediction model in comparison with the traditional multi-location experiment methods allowing the creation of recommended list of potato varieties based on the analysis of unbalanced data sets.