Modification of production systems for year-round marketing

The fruit production in the tropics offers a greater scope to modify a plant's flowering and fruiting cycles than in temperate areas. Changing the normal seasonal flowering cycle offers growers considerable economic advantages, by enhancing the ability to market tropical fruit in the off-season. A grower can cycle different blocks of trees to provide continuous employment for workers, schedule production to avoid the peak periods when gluts occur and often the price is less than the production costs, and can accept orders to deliver fruit at a future date. The practices used to modify the timing of flowering also offers the opportunity to improve product quality and reduced cull losses when coupled with practices such as fruit thinning and bagging. Cold temperatures and photoperiodism determine flower induction in temperate, and subtropical growing areas. The cold season in the subtropics often leads mango, for example, to have only one flowering cycle per year, whereas in the tropics, it might flower two to three times per year. The phenology of many tropical fruit crops and some temperate crops when grown in the tropics can be modified by production practices such as the fertilization and irrigation, pruning and chemical treatments. However, differences occur in the varietal responses to these modified practices. The classic example of a change in the seasonal timing of flowering is pineapple, after it was observed that smoke induced off-season flowering in this photoperiodic species. Water stress and fertilization timing frequently play a significant role in modifying seasonal flowering patterns in tropical species, as does girdling, shading, roots pruning and chemical treatments to stimulate and inhibit growth. Plant growth regulators and inhibitors are used to hasten the completion of the natural phenological vegetative and root growth phases and prepare the tree for flowering. The modification of the natural phenological cycles has raised concerns by some orchardists and researchers that the tree's useful life might be reduced. The reduction in a tree's productive life due to cycling can incur additional expenses to replant and wait for the new planting to mature and produce fruit. It would be necessary to balance the cost of replanting, if needed, with the advantages from cycling trees to achieve higher fruit prices. Examples of crops where flowering and fruiting cycles have been modified, include; carambola, durian, grape, guava, longan, mango, pineapple, rambutan, sweetsop and wax apple. The potential also exists to tailor production practices in other tropical fruit crops to allow year-round marketing of high quality tropical fruit.