Parametric and non-parametric methods for the evaluation of winter rye genotypes by grain yield stability

The analysis of yield stability has become increasingly relevant in recent years due to changing climatic conditions that negatively affect crop yields. It is of utmost importance for farmers to cultivate widely adaptable and yield-stable varieties with high yield potential, as this determines economic predictability and mitigates their risk. Stability is also crucial for plant breeders to create genotypes adapted to a wide range of diverse environments. The aim of this study was to identify high-yielding, stable and adaptive rye landraces and cultivars for commercial and breeding purposes. The trial was carried out from 2014 to 2022 and included 16 cultivars and 7 Bulgarian landraces. The experiment was conducted in a block design with the randomized design of the variants in four replications. Sixteen parametric and non-parametric parameters of grain yield stability were determined. The average of the sum ranks (ASR), the AMMI stability value (ASV), the yield stability index (YSI) and the genotype selection index (GSI) were also calculated. Year had the highest statistically significant effect on the grain yield per hectare. Parametric and non-parametric stability parameters estimated G13, G12, G20 and G21 genotypes as the most stable. ASV identified G13, G18, G12 and G9 as the most stable genotypes, while YSI identified G13, G19, G12 and G18, respectively. GSI classified G13, G12, G18, and G19 as genotypes with the broadest adaptability to adverse climatic conditions. They could serve as source material for rye breeding programs.