The crop that is not a fiber crop is onion.
Fiber crops are plants grown specifically for their fibers, which can be used to make textiles, ropes, paper, and other materials. Cotton, jute, and sisal are all examples of fiber crops.
Cotton is one of the most commonly used fiber crops and is widely used to make clothing, towels, and sheets. Jute is a plant that produces strong and durable fibers, which are used to make burlap sacks and rope. Sisal is another plant that produces fibers that are commonly used for rope and twine.
On the other hand, onion is a vegetable crop that is primarily grown for its edible bulbs. While onion leaves and stems can be used to make fibers, they are not typically grown or harvested for this purpose. Instead, onion fibers are usually considered a byproduct of onion production, and are not used on a large scale. Therefore, onion is not considered a fiber crop.