2) Prof. Alon Samach

Floral induction in olive (Olea europaea L.) is highly sensitive to winter temperature profiles, fruit load history, and environmental variability—factors that pose increasing challenges under desert and warming climate conditions. Experimental evidence shows that flowering depends on the dynamic interplay between prior-year fruit load, which exerts a suppressive “memory” effect, and winter chilling, which promotes the expression of FLOWERING LOCUS T (FT) genes. A heavy crop significantly reduces the proportion of buds forming inflorescences, regardless of tree age or irrigation regime, primarily through inhibition of FT-related gene activation. Controlled studies demonstrate that 10–13 weeks of moderate cold (5–15.5 °C) are essential to induce FT gene expression, while even brief warm spells during this period can suppress flowering. A newly developed dynamic temperature-response model accurately predicts flowering by accounting for the timing and sequence of both cold and warm events, offering significant improvements over traditional chilling unit models. Field research confirms that well-managed older groves can sustain high productivity, provided vegetative vigor and reproductive transition are maintained. Moreover, winter drought stress—despite reducing water potential—had minimal effect on flowering gene expression, underscoring temperature as the primary environmental driver. Molecular evidence regarding the inhibitory effect of Gibberellin on flower induction will be presented. These findings offer a robust framework for sustaining olive cultivation under desert conditions, emphasizing the need for cultivar- and climate-specific management strategies, predictive flowering models, and a deeper integration of physiological and genetic monitoring to mitigate the risks posed by climate variability.