Stability and adaptability concepts of bread wheat (Triticum aestivum L.) in the northwest of Tunisia

Introduction: Stability and adaptability of 25 bread wheat (Triticum aestivum L.) cultivars were evaluated for genotype x environment interaction (G x E) and yield stability across two environments over 2 years (2014 and 2015). Materials and methods: Five improved varieties (Haidra, Salammbo, Tahent, Utique, and Vagua) released in Tunisia and 20 introduced genotypes (V1-V20) have been tested under two contrasted environments during 2 years characterized by different precipitations in the northwest of Tunisia. Several statistical approaches were conducted to evaluate yield stability: (a) regression coefficient (b(i)), (b) deviation from regression (S-di), (c) ecovalence (W-i), (d) Huhn stability (S-li), and (e) AMMI stability value. Results: A standard multifactor analysis of variance test showed that the main effects due to genotypes, locations, and the interaction (genotype x locations) were highly significant. The highly significant interactions indicate that genotypes need to be tested during several years and at different locations for selecting the most stable one. The results showed that all statistical analyses allowed classifying the 25 studied genotypes according to their grain yield level (low, medium, or high), their adaptability to different environments. Conclusion: Tahent variety was confirmed to be most valuable due to its high production level, stability and its adaptability to variable environments including unfavorable ones.