Thinning and Pruning to Overcome Alternate Bearing in Peach Trees

Overview & Synopsis

Different tree fruit loads and intensities of winter pruning were combined in an early-maturing peach cultivar 'Alexandra', sensitive to biennial bearing, so as to assess the impact of the number of fruit per meter shoot length on the regularity of fruit production. Crop load was shown to vary in the next year from a factor of one to a factor of 11, underlining the major incidence of the treatments tested on alternate bearing in peach. There was a close and negative relationship between flower density (number of flower per m shoot length) and fruit density (number of fruit per m shoot length) in the previous year. As a consequence, fruit density and number of fruit per tree were also negatively correlated to fruit density in the previous year, which could then be considered as a major parameter triggering alternate production in peach. A maximal fruit load of four fruit per m shoot length could be recommended for a regular 'Alexandra' peach production. Because peach number per tree was positively correlated to total length of fruit-bearing shoots, light winter pruning should be performed in order to limit the detrimental effect of a weak return bloom on production of the year in progress.