Genotype- and Environment-Dependent Effects of Biostimulant Protocols on Flowering, Maturity, and Stability in White Lupin (Lupinus albus L.)

The decline in cultivating crops like lupin in the Arab region and globally is due to climate change, old local varieties with low yield, and the long cultivation season that delays subsequent crops. This study tested a treatment protocol using zinc sulfate, salicylic acid (SA), and aloe vera extract on three Egyptian varieties: Giza 1, Giza 2, and Giza 3. A multi-environment trial was conducted over two seasons across two contrasting locations. Advanced linear mixed-effects modeling revealed that genotype was the dominant source of phenotypic variance, accounting for 5.8% and 4.9% of the variation in days to blooming (DTB) and days to maturity (DTM), respectively. SA was the most effective, significantly reducing DTB by 10.7% (7.9 days) and DTM by 5.9% (9.8 days) compared to the control. A significant genotype × treatment interaction (p < 0.001) identified Giza 2 as the most responsive cultivar, achieving the shortest DTB (60.0 days) under SA. Variance component and AMMI stability analyses confirmed strong environmental modulation, with treatment efficacy amplified at the site with greater abiotic stress potential. However, Giza 3 with zinc sulfate offers stable performance under high-fertility conditions. Such results suggest that the careful management of genotypes and diverse stimuli under continuous environmental changes can significantly accelerate growth and enhance adaptability, thereby achieving stability and increasing productivity.