Constraints to obtaining consistent annual yields in perennial tree crops. I: Heavy fruit load dominates over vegetative growth

Harley M. Smith, Alon Samach*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

99 Scopus citations


Farmers lack effective methods to achieve and maintain stable production from year to year in many commercial fruit crops. Annual fruit yield within a region often alternates between high and low fruit load and is termed alternate bearing. The underlying cause of alternate bearing is the negative impact of high fruit load on vegetative growth and next year's flowering. In this review, we emphasize common responses of diverse perennials to heavy crop load. We present botanical, ecological and horticultural perspectives on irregular bearing. The later part of this review focuses on understanding how high fruit load dominates over vegetative growth. We discuss sink strengths and putative mobile signals (hormones), perhaps seed-derived. We highlight gaps in current understanding of alternate bearing, and discuss new approaches to better understand fruit load dominance. Assuming the effect of high fruit load may be related to other mechanisms of sink partitioning, other forms of dominance are presented such as apical, first fruit and king fruit dominance. Dominance seems to be enforced, in independent cases through the establishment of a polar auxin transport system from the stronger sink. Once established this somehow perturbs the transport of auxin out of weaker sinks. Possibly, fruit derived auxin may alter the polar auxin transport system of the shoot to inhibit shoot growth.

Original languageAmerican English
Pages (from-to)158-167
Number of pages10
JournalPlant Science
StatePublished - Jun 2013

Bibliographical note

Funding Information:
The AS lab is funded by the Israeli Science Foundation – the Charles H. Revson Foundation (grant no. 1464/07 ), the Chief Scientist Ministry of Agriculture and Rural Development, Israel (Grants # 837-0086-10 , 837-0132-11 ) and by the German–Israeli Project Cooperation (DIP project H 3.1). We apologize to colleagues whose work we could not include due to space limitation. We would like to thank Shimon Lavee, Reuben Hofshi, Jaime Kigel, the editor Jonathan Gressel and anonymous reviewers for their helpful comments.


  • Alternate bearing
  • Auxin
  • Dominance
  • Fruit load
  • Growth cessation
  • Masting


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