The Cavendish banana
Nearly every banana in shops is the same variety, Cavendish. It has no seeds and every plant is a clone, which is both its strength and its weakness.
A giant herb
The banana plant is not a tree. Its 'trunk' is a pseudostem of rolled leaf bases, and the real stem is the corm underground.
The bunch
Each plant flowers once. The stalk bends over and carries hands of fingers, with the purple male bud at the tip; the fingers curve upward toward the light.
Three sets, no seeds
Cavendish cells have three chromosome sets, which cannot divide evenly into fertile pollen or eggs. The fruit grows without seeds, leaving only tiny dark specks.
Grown as clones
Since it cannot breed, farmers plant suckers that sprout from the corm. Each is an exact copy, so whole plantations are genetically identical.
History repeats
The earlier export banana, Gros Michel, was also a clone and fell to Panama disease in the 1950s. Cavendish resisted that fungus and took its place.
The new threat
Tropical Race 4, a new strain of the fungus, kills Cavendish and spreads through soil. With no genetic variety to fall back on, growers are racing to breed resistant bananas.