Genotype-by-environment interactions and seed yield stability of narrow-leaf lupin sweet varieties (Lupinus angustifolius L.) based on AMMI and GGE biplot analyses

Narrow-Leaf lupin sweet varieties (Lupinus angustifolius L.) is a leguminous crop valued for its protein-rich seeds, which are used as both human food and livestock feed. Beyond its nutritional value, this plant is crucial for improving soil health because of its natural nitrogen-fixing ability. Despite its critical status as a valuable multipurpose crop, narrow-leaf lupin sweet varieties remains significantly underutilized, with cultivation limited by insufficient data on its performance across diverse environments in Ethiopia. To overcome this limitation and unlock sweet lupine's performance potential, this study evaluated seed yield of five varieties across three environments over two growing seasons. The analysis employed Genotype-by-Environment Interaction biplot and Additive Main Effects and Multiplicative Interaction methods to assess genotype performance, stability, and adaptability, as well as to identify environments ideal for distinguishing genotype responses. This study also employed parameters such as cultivar superiority, AMMI Stability Value, and Genotype Selection Index, which provide valuable insights into the performance of genotypes under varying environmental conditions. The results showed that G3 (Probor) and G2 (Vitabor) were the highest-yielding, stable, and best-adapted genotypes. These two narrow-leaf lupin sweet varieties demonstrated greater resilience to environmental fluctuations and enhanced suitability for sustainable future, making them preferable choices for local farmers. They also contribute to increased resilience against climate variability, thereby supporting long-term agricultural sustainability. The AMMI model confirmed that genotype-by-environment interaction has a significant impact on seed yield. These findings offer important insights into the genetic potential of narrow-leaf lupin sweet varieties, which can assist breeding programs in developing high-yielding, adaptable, and stable genotypes for the study area and other areas with similar agro-ecological conditions.