NEW TRAINING AND MANAGEMENT SYSTEMS FOR LOW-CHILL STONEFRUIT IN SUBTROPICAL AUSTRALIA

New training and management systems have been developed for growing low-chill stonefruit under the subtropical environments of Australia. Recommended cultivars are planted at densities of 1800 trees/ha and trained onto the open V trellis system with sub-leaders espaliered. Previous studies have shown that the soil-applied growth retardant paclobutrazol controlled excessive shoot extension growth which greatly reduces fruit quality. In this study, we found that foliarly-applied growth retardant prohexadione-Ca had only a mild growth retarding effect. We also compared the effects of standard bird netting vs. fruit fly exclusion netting on fruit quality. Fruit fly exclusion netting increased Brix concentration of fruit by as much as 15% compared with trees netted with standard bird netting. Our studies also showed that the ethylene inhibitor ReTain, applied one week prior to harvest, was highly effective in delaying fruit maturity and increasing fruit firmness and size by as much as 28% at harvest but responses were cultivar dependent. These results are promising, but further studies are needed before being able to make recommendations that contribute to sustainable production.