Influence of post-harvest deficit irrigation and pre-harvest fruit thinning on sweet cherry (cv. New Star) fruit firmness and quality

SummaryThe effects of tree water stress on sweet cherry (‘New Star’) fruit quality during post-harvest and pre-harvest fruit thinning were evaluated in a 2-year field experiment (2005 – 2006). Four different treatments were applied: (i) fully irrigated (Control), in which irrigation was scheduled according to a water budget approach; (ii) RDI-80%, in which the crop received 0.8× Control irrigation during post-harvest and was irrigated like the Control during pre-harvest; (iii) RDI-50% in which the crop received 0.5× Control irrigation during post-harvest and was irrigated like the Control during pre-harvest; and (iv) RDI-80%-T in which irrigation management was the same as for RDI-80%, but fruits were only thinned 1 month prior to harvest in 2006. No significant effects on fruit load or yield were observed in 2006 as a consequence of the 2005 irrigation treatments. However, the RDI-50% treatment produced a noticeable advance in ripening, as evaluated from the percentage of fruit harvested at the first pick. Post-harvest water stress did not affect fruit quality at harvest, but slightly reduced fruit firmness (FF) and soluble solids content (SSC) after cold storage, with no significant variation in fruit flesh red colour (expressed as hue angle). Fruit-thinning reduced the fruit load by 38% compared to Control trees, and significantly increased fruit fresh weight (FW), FF, and SSC for cherries with similar flesh colour to the other treatments. Reducing irrigation by 50% during post-harvest advanced the harvest date (RDI-50% treatment), but did not provide any advantage in terms of fruit quality.