Question

Which of the following was responsible for the extinction of the Banana Variety "Gros Michel" from the market due to its high susceptibility?

• A. Fusarium oxysporum f. sp. cubense race 1
• B. Fusarium oxysporum f. sp. cubense race 4 or tropical race 4
• C. Ralstonia solanacearum race 2
• D. Ralstonia solanacearum race 4

Hint:

Think of the historical banana crisis: Gros Michel was destroyed by Foc Race 1.
Today's Cavendish cultivar is threatened by Tropical Race 4 (TR4).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Panama disease, also known as Fusarium wilt of banana, is a devastating vascular wilt disease caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc).
Different races of the pathogen target specific cultivars of bananas.

Step 2: Detailed Explanation:
During the first half of the twentieth century, the global banana trade relied almost entirely on a single sweet cultivar known as "Gros Michel."
This cultivar was highly susceptible to Fusarium oxysporum f. sp. cubense Race 1.
The pathogen infects the roots, colonizes the xylem vessels, blocks water transport, and causes leaf wilting and plant death.
Because the banana plants were monocultured clones, the disease spread rapidly through plantations across Central and South America.
By the 1950s, Foc Race 1 had practically wiped out commercial production of "Gros Michel," leading to its commercial extinction.
To save the banana industry, growers transitioned to the resistant "Cavendish" cultivar.
Foc Tropical Race 4 (TR4) is a newly emerged strain that currently threatens Cavendish bananas, but the historical destruction of "Gros Michel" was caused specifically by Race 1.
Ralstonia solanacearum is a bacterium that causes Moko disease in bananas, which is different from Panama wilt.

Step 3: Final Answer:
Fusarium oxysporum f. sp. cubense race 1 is the correct option.