A farmer wishes to increase the yield of his sugarcane crop. He is advised to spray a specific plant growth regulator that increases the length of the stem, thereby increasing the yield by as much as 20 tonnes per acre. Which of the following phytohormones should be sprayed?

Step-by-step solution

Sugarcane stores carbohydrates as sugar in their stems. Spraying sugarcane crop with gibberellins increases the length of the stem, thus increasing the yield by as much as 20 tonnes per acre. Ethylene is primarily associated with fruit ripening and senescence. Cytokinins promote cell division and delay leaf senescence. Abscisic acid acts as a general plant growth inhibitor and an inhibitor of plant metabolism. Answer: Gibberellic acid