Crop load and time of thinning interact to affect fruit quality in sweet cherry
Bound, SA and Close, DC and Quentin, AG and Measham, PF and Whiting, MD, Crop load and time of thinning interact to affect fruit quality in sweet cherry, Journal of Agricultural Science, 5, (8) pp. 216-230. ISSN 0021-8596 (2013) [Refereed Article]
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.