Question

Onion is propagated through its
A. Tubers
B. Bulbs
C. Seeds
D. Rhizomes

Answer 1

Onion undergoes asexual reproduction through vegetative propagation. In vegetative propagation, the vegetative part of a plant gives rise to a whole new plant. It can be through leaves, roots, and stems. The whole new plant generated is the exact copy of the original plant.

Complete answer:
The development of a whole new plant from a specialized reproductive structure is the principle of vegetative propagation. Some of the structures used here are stolon, rhizome, tuber, bulbs, etc.
A tuber is a fleshy, thickened, underground stem of a plant, usually containing stored starch. These structures are generally present in potatoes.
Therefore, option (a) is not correct.

Seeds are the most common methods of reproduction but it cannot be called vegetative propagation. This is because the development of seed is only possible when there is fertilization which is a part of asexual reproduction. Onion does not undergo sexual reproduction.
Therefore, option (c) is also incorrect.

A rhizome is a horizontal underground stem of a plant that sends out roots and shoots from its nodes, generally found in ginger. It stores minerals and conducts water.
Therefore, option (d) is also incorrect.

The bulb is a type of underground stem modification that is observed in Onion. It is pear-shaped and located under the ground. Numerous fleshy scales enclose the terminal bulb and a disc-shaped stem. The base of the bulb gives rise to adventitious roots. It is non-green and the main function is the storage of food and perennation.

Hence, the correct answer is option (B).

Note: Vegetative propagation is very beneficial since the genetic configuration remains intact, but this is also its drawback. It does not allow genetic variation in species which prevents new varieties and better offsprings. A similar genetic constitution can lead to low yield which is not good for the crop health and economy.