ASSESSMENT OF GRAIN YIELD STABILITY AND RELIABILITY IN SOME WINTER WHEAT VARIETIES

Considering the continued and unpredictable variation of climatic condition, the yield stability has become an important topic in wheat breeding. This study evaluated the grain yield of 11 winter wheat varieties with different genetic and ecologic origin during three years, to compare  the effects of genotype, year and genotype × year interactions and to determine their stability and reliability for cultivar recommendations. The climatic conditions during the three years had the highest contribution (80.03%) to the yield variability of wheat, while the varieties had a lower influence (11.41%), and the variety x year interaction contributed only with 8.56% to the total variation. In 2020, the climatic conditions were significantly more favorable than in 2018–2019, allowing obtaining yield increases of 33.82-44.20%. Also, in 2018 there was a higher favorability of the growing conditions compared to that of 2019, associated with significant yield increases of 7.75%. The highest yield stability was observed in Boema and Galio varieties, on the background of a non-crossover genotype x environment (GE) interaction. The stability of these varieties has been associated with different yield levels, above the experience mean in Galio and below the experience mean in Boema, respectively. In Akteur and Josef varieties, the yield was strongly influenced by the GE interaction, being associated with lower levels than the experience mean. On the background of high occurrence probabilities (0.75–0.95) of unfavorable environmental conditions for wheat crop, Galio and Laurenzio varieties would have the highest yield reliability, associated with values of 5173–6328 kg/ha (Galio) and 5101–5979 kg/ha (Laurenzio). As such, given the results of all stability parameters, it turns out that the Romanian varieties showed a good adaptation to the local ecological conditions compared to most of the foreign varieties.