Advantages and Disadvantages of Cultivating Mangoes (Mangifera indica L.) under Subtropical Conditions and Potential of Greenhouse Cultivation of Mango

Although the mango is grown mainly in tropical climates, there are significant advantages to cultivating mangoes in the subtropics, where cooler winter temperatures improve flower induction, and both early bearing in younger trees and lower annual growth rates favour high-density planting options. It is not surprising that the best mango yields are obtained in the subtropics with Israel leading the FAO world statistics about mango yield. The reasons that explain these successful results are studied in this paper are the following: climatic factors; genetic considerations and cultural techniques including greenhouse cultivation.. Obviously not all are advantages about mango cultivation in the subtropics. While cold spells can damage vulnerable young trees and sustained low temperatures can provoke alternate bearing phenomena in late season cultivars, the chief disadvantages of cultivating mangoes in the subtropics are the need of avoiding flowering in young trees, the prime cause of premature aging, and the need to control annual flowering so that it coincides with temperatures conducive to good fruit set. Special strategies to control flowering time include the use of giberellic acid to delay the terminal flowering, manual or chemical removal of the terminal flowering and even allowing powdery mildew to destroy the first flowering wave to obtain a second axillary flowering. Other technique regularly practiced for the late cultivar 'Keitt' in the South of Spain, both in the open and under greenhouse, consists in the 'machete' removal at the beginning of the Spring of all terminals produced in the 'on' year and eliminating also the few fruits produced in the 'off' year. This practice allows a higher build-up of carbohydrate reserves for the 'on' year, which gives rise to a biennial production of an excellent crop of fruits with the appropriate size and colour demanded by the market. The cultivation of mangoes in the subtropics is largely based on monoembryonic cultivars, which, due to their cooler area of origin are, in principle, better adapted to subtropical conditions. Efforts of the breeding programmes for subtropical mangoes are also concentrated in these type of mangoes, while the potential of mango rootstocks and also of other Mangifera species for mango cultivation both in the tropics and in the subtropics are still to be explored. Much research has been dedicated to cultural techniques specific for the subtropics with density considerations and training practices deserving special attention. as a consequence of the fact that the reduced number of flushes annually produced favours shorter distances between plants and even the possibility of high density plantings. Greenhouse cultivation - unheated, in many areas of the subtropics - facilitates cultivation of mangoes in the subtropics. The main advantages of greenhouse cultivation includes: i) Shortening of the juvenile period; ii) Protection from adverse climatic conditions, including avoiding sunburn; iii) Increase flowering and fruit set, due to higher diurnal temperatures and increase of foliar surface, which in turn increase photosynthesis; iv) Easier control of irrigation and possibility of obtaining out of season production through imposing water stress; v) Possibilities of extending harvesting season; and vi) Easier control of pests and diseases. Mangoes under greenhouse are also specially adapted to cultivation on trellises which facilitates pest control and harvesting. These cultivation advantages must be off-set against the initial infrastructure costs as well as the obligatory and timely provision of pollinating insects at flowering time. Prior, in-depth economic studies are thus required in order to ensure that the investment will be profitable in the long term.