BANANA - THE CHALLANGE IN MALAYSIA

BANANA (Musa spp) are grown in 122 countries, with a cultivated area of 3.8 million hectares and a total production of 56.4 million metric tonnes. In Malaysia, banana is the second most widely cultivated fruit, covering about 26,000 ha with a total production of 530,000 metric tonnes. About 50% of the banana growing land is cultivated with Pisang Berangan and the Cavendish type, and the remaining popular cultivars are Pisang Mas, Pisang Rastali, Pisang Raja, Pisang Awak, Pisang Abu, Pisang Nangka and Pisang Tanduk. Bananas are cultivated for local consumption by smallholders, and only about 12% of the total production is exported, mainly to Singapore, Brunei, Hong Kong and the Middle East. However, banana production in Malaysia has decreased because of an increasing threat of diseases (particularly Fusarium wilt), high labour costs and marketing issues.The present research program was initiated with the objective of improving the important dessert bananas in Malaysia. This includes production of resistance or tolerance to Fusarium wilt or Panama disease, short plant stature, early fruiting, and high bunch weight. Banana cultivars are vegetatively propagated clones and are generally triploids and sterile. Tissue culture techniques have been exploited for (a) propagation of selected lines or natural variants; (b) generation of somaclones; (c) production of meristem pieces for in vitro mutagenesis and polyploidy induction; and (d) zygotic embryo culture to generate seed progenies for genetic and molecular studies.

 
Banana is the second most commonly grown fruit crop in Malaysia. Overall banana production has decreased due to the increasing threat of Fusarium wilt disease, high labour costs and marketing issues. This program was initiated to improve banana cultivars by induced mutations and biotechnology, especially to produce mutant varieties with improved traits such as Fusarium tolerance, short stature plants, early fruiting and high bunch weight. Banana shoot-tip cultures were most suitable for micropropagation for large-scale plant production. Commercial companies have adopted this method, and they produce 1.3 million plants annually, with approximately 0.5% somaclonal variation. However, the cost of production of in vitro plants could be reduced by low-cost micropropagation. Somaclonal variation has been effective in banana for the selection of useful somaclones, e.g. early flowering and tolerance to Fusarium wilt. In Novaria, an early flowering mutant, 7% of the plants survived in the Fusarium 'hot spot' for 3 years. Consequently, somaclonal variation is being used as a strategy to select useful mutants. Since bananas are mostly sterile polyploids, highly heterozygous, and propagated vegetatively, genetic improvement by cross-breeding is an insurmountable task. On the other hand, mutation techniques are highly suitable for banana improvement. Pisang Berrangan (AAA), a popular dessert banana variety, was gamma-irradiated at several dosages (20-60 Gy). The highest percentage of variants, such as changes in leaf coloration and leaf texture, leaf deformation, stunted growth etc., was obtained with 45 Gy treatment. The double-tray system was developed for the selection of mutants tolerant to Fusarium wilt. Among selected plants showing tolerance to Fusarium wilt, none survived field evaluation under Fusarium 'hot spot' conditions. Molecular characterization with RAPD of resistant and susceptible banana types showed random variation for different markers. However, four primers showed bands specific to either resistant or susceptible seed progenies, but could not provide information on the degree of co-dominance. That's all for this article... to be continue.

By
M Anem,
Senior Agronomist,
Kg Sedilii Besar Banana Group Farming,
Sedili, Kota Tinggi,
Johor, Malaysia.
(2 Rejab 1436H)