Productivity is negatively related to shoot growth across five mango cultivars in the seasonally wet-dry tropics of northern Australia

Introduction. Mango productivity is low in seasonally wet-dry tropical areas where breeding programs require information on factors affecting productivity of mango cultivars. Specifically, our study tested a novel hypothesis that, among Australian- and Florida-bred cultivars, the greater growth of vegetatively vigorous cultivars would contribute to lower levels of fruit production in comparison with less vegetatively vigorous cultivars, in a wet-dry tropical environment. Materials and methods. A field experiment was conducted on trees of the cultivars 'Kensington Pride' and 'Strawberry', both polyembryonic cultivars, and 'Haden', 'Irwin' and 'Tommy Atkins', all monoembryonic cultivars. Results. Shoot growth was recorded over two years; in both years the polyembryonic cultivars produced more new shoot length than the monoembryonic cultivars; 'Irwin' was the least vigorous cultivar in both years. Across cultivars, there was a negative relationship between normalised (by flowering intensity and canopy area) fruit number or yield and vegetative vigour as represented by new shoot length. Conclusion. The results supported the hypothesis that the greater shoot growth of vegetatively vigorous cultivars contributed to lower levels of fruit production in comparison with less vegetatively vigorous cultivars in a tropical environment. This is the first study which demonstrates that the extent of seasonal shoot growth had a fruit production cost for mango.