Crop load and time of thinning interact to affect fruit quality in sweet cherry

Balanced crop load is key to the production of export-quality cherries. We investigated the level and timing of crop load regulation on fruit quality. Fruit diameter was similar between 1 and 2 bud/spur treatments but was significantly lower in the 4 bud/spur treatment at all thinning times in ‘Van’ in the 2010/11 season. In contrast ‘Sweetheart’ fruit diameter was only decreased at 6 and 8 WAFB in the 4 bud/spur treatment in 2010/11. This decrease in ‘Sweetheart’ was associated with significantly higher soluble solids and starch reserves in leaves, stem, trunk and roots 2-weeks post-harvest in trees thinned at dormancy, relative to trees thinned 8 WAFB. Fruit flesh firmness significantly increased with decreased crop load irrespective of time of thinning in ‘Van’ in 2010/11. In contrast flesh firmness was significantly higher in the 1 bud/spur treatment and similar between other treatments in ‘Sweetheart’ in 2010/11. In 2011/12 flesh firmness, soluble solids and colour significantly increased whilst fruit weight and TA significantly decreased 28 days post-harvest relative to at-harvest values. Sweet cherry fruit quality is optimised through attaining crop load of approximately 10 fruit per cm2 of limb cross-sectional area through thinning at dormancy or full bloom.