Tropical & Subtropical Fruits

Facts and myths of bearing problem

Operation of 'on' and 'off ' phases

• The phrases 'on' year and 'off year are used to refer to the years of 'normal' and 'sub-normal' or 'no crop' respectively.
  
• However, these phrases are in a way misnomers in so far as their reference to a given year is concerned since not hundred per cent of trees in an orchard would be either 'on' or 'off in any year.
• In any given year, the 'on' or 'off phases may be confined to individual trees or portion/branches of trees depending on the previous history of the given tree with regard to the magnitude of the crop load that had been carried in the previous fruiting season (Jan.-June).
  
• Further, a set of two identical adjoining trees may behave variably during flowering season of a given year: one of them may be in 'on' phase while the other may be in 'off phase which is dependent on the magnitude of crop load harvested in the previous year.
  
• This fact therefore, rules out the role of climate in causing 'on' or 'off phases in a given group of trees.