Fruit canopy position and panicle bagging affects yield and quality of 'Tai So' lychee

Abstract

To determine the potential for fruit bagging to improve the quality of lychee, panicles on the northeast (NE), southeast (SE), southwest (SW) and northwest (NW), and at the top and bottom of the canopy of 12-year-old `Tai So' lychee trees, were enclosed in paper bags at early fruit set, at 1/2–3/4 fruit fill, and just before fruit colouring (corresponding to 80, 42 and 28 days before harvest). At commercial maturity, panicles from the NE and NW aspects and from the upper canopy had the greater number and mass of fruit per panicle, than panicles from the other parts of the canopy. Bagging had no significant (P<0.05) effect on panicle yield. Fruit from the NW aspect were of lower visual quality, due mainly to light and dark brown blemishes on the skin, rather than the colour of the red portion of the skin. Lower canopy and NE fruit were less red (higher hue angle; h°), but there was little effect of canopy height on visual quality. Bagging increased the percentage of fruit in first class, mainly because of increased visual quality of fruit from the NW and SE aspects. The percentage of second class fruit was not affected by bagging, but the percentage rejects was reduced. Unbagged fruit had a lower Chroma (C*) and a higher h°, especially in fruit from the NE. Fruit from the NE and NW aspects and from the lower canopy, had lower brix/acid ratios. Thus, bagging has the potential to improve fruit quality and red colour with no negative impact on yield.