Genetic resources from other species and botanical varieties

The wild pineapples, Ananas comosus var. ananassoides (Plate 2) and A. comosus var. par-guazensis (Plate 4), constitute the main reservoir of genetic diversity. The former is generally considered the most drought-resistant pineapple. Its fruit is often seedy, with white to yellow pulp, which is firm and fibrous. Sugar and acid contents are high and it has a good flavour and aroma. The core is narrow. According to Collins (1960), crosses between A. comosus var. comosus and A. como-sus var. ananassoides yield hybrids that are entirely comparable with crosses between cultivars, with highly variable sugar and acidity values. Mean acidity value is intermediate between those of the parents, but the average sugar content of the hybrids is much closer to that of the A. comosus var. ananassoides parent. A. comosus var. ananas-soides is a potential source of resistance or tolerance to wilt, nematodes (Meloidogyne javanica, Rotylenchulus reniformis) and crown and root rot (Collins and Hagan, 1932; Hagan and Collins, 1932; Collins, 1960; Ayala, 1961; Ayala et al., 1969; Sipes and Schmitt, 1994). A. comosus var. parguazensis is less variable. It has a globular fruit with relatively wide flat eyes and a white and fibrous pulp. Resistance to fusariosis is variable in A. comosus var. ananassoides and A. comosus var. parguazensis (de Matos et al., 1991).

A. comosus var. bracteatus (Plate 6), first cultivated for the fruit and as a living fence, is now widely used as a tropical garden ornamental. Its variability is very limited. It grows well on poor and dry soil and it is well adapted to cool conditions and altitude. The fruit is small to medium, with white fibrous flesh, a small core and an average sugar and acid content. It is resistant to heart rot, root rot and fusariosis (de Matos et al., 1991). Studies on nematode resistance produced contradictory results (Collins, 1960; Sipes and Schmitt, 1994). Crosses with A. comosus var. comosus yield hybrids with fruits of good size and weight and a wide variation in flavour (Collins, 1960).

A. comosus var. erectifolius (Plate 3) has been cultivated for its long and strong fibres. In the past decades, a dark red cultivar has also been exploited as an ornamental for the European cut-flower market. This trait is controlled by a single dominant gene (Cabral et al., 1997). The use of A. comosus var. erecti-folius in breeding for dual-purpose (fruit and fibre) cultivars has been envisaged in the Philippines (V. Villegas, Fort-de-France, 1992, personal communication). A. comosus var. erectifolius is resistant to heart rot and root rot (Collins, 1960) and relatively tolerant to nematodes (Sipes and Schmitt, 1994).

Ananas macrodontes (Plate 1) has been mainly used as a source of fibre. As with all other pineapples, it is resistant to drought but it also tolerates temporary flooding. It is resistant to heart rot, root rot, wilt and fusar-iosis (Collins, 1960; de Matos et al., 1991). When selfed, A. macrodontes shows little variation, indicating that it is relatively homozy-gous (Collins, 1960). Hybridization with A. comosus var. comosus produces 5-10% fertile seeds, most of which are tetraploid. These tetraploids are fully fertile.

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