The FSAB attracted ca. 100 participants from 26 countries and all continents. Topics included research on biennial-bearing-affected crops like pistachio, olive, almond, (Satsuma-)mandarin, litchi and mango and cultivars 'Honeycrisp', 'Kanzi', 'Fuji' und 'Elstar' in apple with the following results: (1) The 3-fold increase in leaf carbohydrates in off-years (low yielding) and carbohydrate shortage in 'on years' (high yielding) as an indicator of alternate bearing in fruit crops was commonly agreed. Once the tree has overcome its juvenile phase and its chilling is fulfilled, the flowering gene 'flowering locus t' is synthesized in the leaf veins in equal amounts in both on and off years and transported in the phloem to the bud meristem of the bourse shoot causing an apparent discrepancy in interpretation. Research on apple in Israel now showed that the heavy fruit load in high yielding 'on years' induced gene expression of the flowering inhibitor Terminal flower 2 (TFL 2) in the bud meristem, thereby preventing the function of the flowering gene flowering locus T (FT) after its import from the leaf veins to the meristem enabling an elegant explanation of the regulation of alternate bearing as a result of heavy fruit load in the previous year. (2) Early flowering in litchi was associated with a cold temperature sensitive promoter of the flowering locus t (FT) in contrast to late flowering litchi-a valuable natural mechanism, which could be employed in crops and regions prone to late frost as experienced 19-20 April 2017. (3) Developing seeds in apple fruitlets synthesize and export gibberellin GA7 to the bud meristems, where GA7 inhibits flowering; GA4 may reverse this effect. Overall, countermeasures to combat biennial or alternate bearing include early thinning in terms of young trees and early during flowering and fruit set, the concept of resting spurs viz branches without fruit, ethephon application in June in 'on years' and, as a consequence of climate change, frost protection, breeding and cultivation methods including crop load management, winter and summer pruning.
