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Pineapple is one of the most important fruits, with large production in tropical and subtropical regions and great appreciation by consumers all over the world. The pineapple plant has many specific morphological, anatomical and physiological characteristics that determine crucial aspects of pineapple crop management, such as flower induction, water use and vegetative methods of propagation. The use of sexual reproduction of pineapple is restricted to breeding purposes carried out by research institutes looking for new hybrids with improved agronomic characteristics. Seeds are only produced if cross pollination among varieties occurs. Commercially pineapple has to be propagated by vegetative material, an asexual reproduction, without new combinations of genes. Some types of propagules are naturally produced by the plants and called conventional planting material. Its availability and quality depend on many factors, especially cultivar and environment. Management techniques of this material have been continuously developed and will be addressed. In addition to the conventional planting material, which in many situations is not sufficient to assure expansion or at least maintenance of the cultivated area, several other methods of vegetative propagation of pineapple have been studied and made available along the last decades and will also be discussed, involving techniques of stem sectioning, apical growing point gouging and chemical treatment for transformation of flowers into plantlets. Stem sectioning has been especially interesting, as it is mostly done using plant residues available at low cost, and is a rather simple method suited for multiplication and production of disease-free planting material in nurseries. Gouging and chemical treatment are less practiced, but can be applied in ratoon crops, thereby avoiding the loss of the first cycle fruit. Chemical treatment usually results in rather small plantlets, that must be further grown in nurseries before planting them in the field. And finally micropropagation will also be focused, as in vitro production of plantlets is a very important method of multiplication of new pineapple varieties, but this method yet has not been transformed into a common commercial way of pineapple propagation due to the final high cost and to the still high risks of incidence of somaclonal variations among the plantlets produced.

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Pineapple, Ananas comosus L. Merr., cultivars differing in resistance to fusariose were examined for the phytotoxic effect of culture nitrate (CF), and fusaric acid (FA) isolated from Fusarium subglutinans (Wollew & Reinking) Nelson, Toussoun & Marasas. The possibility of using these substances on F1 hybrids as selection agents for resistance was also evaluated. The phytotoxic effect of these substances was assessed in pineapple plantlets from tissue culture by placing them on wounded leaf segments. The resistance level of the F1 hybrids and cultivars under natural conditions was measured in greenhouse field tests. The susceptible cultivars proved to be the most sensitive in each test, whereas resistant cultivars showed resistance to CF. FA affected all the cultivars independently of the degree of resistance of the cultivars The presence of other metabolites in CF was responsible for the screening effect between the varieties. Using CF as selection criteria allowed the selection of resistant plants with behaviour quite similar to plants where the fungus itself was used as the selection agent.

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