ASPECTS OF DELAYED HARVEST OF HASS AVOCADO (PERSEA-AMERICANA MILL) FRUIT IN A COOL SUBTROPICAL CLIMATE .2. FRUIT SIZE, YIELD, PHENOLOGY ANDWHOLE-TREE STARCH CYCLING

When avocado fruit of the late maturing 'Hass' were tree-stored until November (early summer) in the cool, mesic, subtropical Natal midlands , fruit size at a warmer site increased with most fruit of count 18 (2 11 to 235 g) in July and count 14 (266 to 305 g) in November. This com pared with the majority of fruit at a cooler site averaging count 16 ( 236 to 265 g) in August and count 14 in November. Results also showed that late hanging did not necessarily result in lower yields of the fo llowing season's crop. In fact where fruit were left to hang late, hig h yields were recorded in the third consecutive year of the trial. Ann ual average trunk bark starch concentrations, sampled monthly, althoug h significantly higher in July (early) harvested trees (ca. 4.8%) were not depressed much in trees harvested in August, September, October a nd November (ca. 4.1%). In addition, there were no significant differe nces in annual average trunk bark starch concentrations from August to November. The harvest by month interactions showed that although star ch concentrations in July harvested trees reached the highest peaks (c a. 12%) they subsequently dropped to the lowest troughs (ca. 2%) indic ating that starch was probably allocated to vegetative growth in prefe rence to the following season's crop. These results suggest that under good management and the experimental conditions of this study, late h anging of 'Hass' fruit may be practised without a significant depressi on of tree vigour.