Ananas comosus MD2 pineapple

Pineapple (Ananas comosus) is one of the most economically important tropical fruits within the Bromeliaceae family (Duval et al., 2001). It is the most highly traded tropical fruit. Pineapple is a perennial herbaceous and monocotyledonous flowering plant whereby it sends up a flower stalk from that central point. Generally, it is usually asymptomatic and has a range of height and width of 0.91 to 1.98 m (Bartholomew et al., 2003). In Malaysia, we have many varieties, namely Moris (AC1), Sarawak (AC2), Gandol (AC3), Maspine (AC4), Josapine (AC5), Yankee (AC6), Moris Gajah (AC7), N36 (AC8), MD2 (AC9), and many more. Among all, MD2 is the most favourite variety due to its super sweet content and yellowish flesh that commonly involved in food and beverage industry.

Top pineapple producing country is Costa Rica, followed by Philippines and Brazil. Malaysia produces about 330k tons annually. For the Southeast Asian region, Indonesia is among the third largest pineapple producers after the Philippines and Thailand with a contribution of around 23%. Pineapple is mostly consumed worldwide as fresh fruit due to its rich flavour, taste, and size. Consumed this way, it can be an excellent source of vitamin A, C, vitamin B1, vitamin B6, manganese, magnesium, iron, copper, phosphorus, and dietary fibre (“Fresh Pineapples,” 2008). It has no starch and consumers only need to peel, core, and slice the pineapple for consumption. Canned pineapple has a wide market as processed fruit. There are a great variety of the canned presentations such as whole, slices, or rings, fingers or spears, cubes, chunks, wedges, and tidbits.

Plain cans are used to pack the fruit because they do not contain tin plate which dissolves due to the fruit acid (Lobo & Paull, 2017). Sometimes the fruit is packed in syrup to hold its colour, shape, and flavour or it can be canned with water or fruit juice to reduce the sugar content. Other downstream products can be made from the pineapples are dried fruits, frozen pineapple, pineapple juice, pineapple jam, and meat tenderizer (bromelain). Pineapple leaf fibre is a hair-like material in elongated pieces similar to thread. The leaf fibre is a comprised mainly of cellulose (Bongarde & Shinde, 2014).

The seeds of these plants are very slow to germinate and therefore are not used for commercial purposes. This bromeliad is routinely propagated vegetatively by means of various vegetative parts, organs, or tissues such as:

1. basal suckers originating from buds below ground level,

2. hapas, which are shoots developing at the base of the peduncle,

3. leafy branches arising from buds in leaf axils,

4. slips, which grow out of the peduncle below or at the base of fruit,

5. crowns, arising from the upper part of the fruit, and

6. butts or stumps from the mature plant (Rangon, 1984).

In case of industrial scale production suckers and heaps are also used (Firoozabady and Gutterson, 2003). The tissue culture method of pineapple comes into the play to increase the selectivity of the desired traits coupled with a high multiplication rate. Following the standard tissue culture method (Mathews and Rangan, 1979; Zepeda and Segawa, 1981; Fitchet, 1990; Fitchet-Purnell, 1993; Kiss et al., 1995; Gangopadhyay et al., 2005) much higher rate of multiplication (40 to 85 fold in a 13 month period) was obtained.

Pineapple crops contaminated with viruses affect production and may lead to mealybug wilt of pineapple (MWP) disease which can be found in all pineapple crops in high density growing areas throughout the world (Sether et al. 2001). Mealybug wilt of pineapple symptoms are morphologically evident on plant leaves displaying leaf downward curling, reddening, wilting, or gradual dying of the tips (Sether et al., 2001; Sether et al., 2005).

Plant tissue culture is about one of the major option to develop an efficient and economical micropropagation protocol for the large scale propagation of pineapples. The micropropagation protocol has now become fairly standardized for some important cultivars of pineapple and with minor changes can be applied to newly derived ones. Propagation in temporary immersion bioreactors (Espinosa et al., 2002) which claims to be an improvement over the existing micropropagation protocol, reports a better performance of such plantlets over those propagated by conventional methods of micropropagation.