Tuesday, February 11, 2014

Monoculture I

Monoculture:  The Enemy of Biodiversity



All too often business interests factor in only short-term profits and losses for the benefit of a relatively narrow segment of the world’s population.  Instead of respecting the varieties within a plant species, they seek to cultivate only those members that best suit commercial needs, displacing other members of the species that occur naturally in their own given ecosystems.
One example is the proliferation of the popular Cavendish banana, one of a few commercially valued hybrids of only two species of banana:  Musa acuminata and Musa balbisiana.  In addition to displacing naturally occurring species and possibly negatively affecting their role in their respective ecosystems, the new commercial strains can be vulnerable to unforeseen problems which, at their worst, can even threaten the new species itself with extinction.  In the case of the Cavendish, a disease called Fusarium wilt produced by strains of a soil fungus, Fusarium oxysporum f. sp. cubense, (abbreviated as Foc) threatens the propagation of the banana in some regions of Southeast Asia.  A strain of Foc, which thrives in the soil conditions brought about by monoculture, eradicated the Gros Michel cultivar, the main exported banana variety from the nineteenth century until the 1950s.
Currently there are efforts underway to genetically engineer Gros Michel bananas for resistance to the original Foc strain but results have been uncertain.  Most of the world’s people eat bananas grown by smallholder farmers in low-income countries where hundreds of cultivars are farmed.  Biodiversity is believed to make these bananas more resistant to Foc-TR4 but the Cavendish, top banana in American and other industrialized nations’ supermarkets, could be headed for oblivion, destroying a popular fruit and a close-to-2.5-billion-dollar industry.


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