Which of the following crop-effect pairs is correctly matched for the agricultural application of ethylene?

Step-by-step solution

Ethylene is a widely used gaseous plant growth regulator in agriculture. Evaluating the given pairs: - Pineapple - Synchronising fruit-set: Ethylene is used to initiate flowering and synchronise fruit-set in pineapples. (Correctly matched) - Sugarcane - Increased internode length: This effect is achieved by spraying gibberellins, which increase the length of the stem. (Incorrectly matched) - Tomato - Induction of parthenocarpy: Auxins are widely used to induce parthenocarpy in tomatoes. (Incorrectly matched) - Cucu