New plants from one parent

Every living thing is born, grows, and one day dies. Life goes on because, before that, it makes new individuals of its own kind. This is reproduction. It happens in two ways:

• Asexual: just one parent. The young are almost exact copies of the parent.
• Sexual: two parents. The young are a mix of both: perhaps height from one parent and curly hair from the other.

New plants from one parent. In vegetative propagation, a new plant grows from a growing part of the parent, not from a seed:

• Potato and ginger are fleshy underground stems. (Yes, a potato is a stem, not a root: leave one in the kitchen and it sprouts.)
• Money plant and sugarcane grow from pieces of stem.
• *Bryophyllum* grows tiny new plants along the edges of its leaves.

There is only one parent, so the new plants are genetically identical to it.

Gardeners and farmers use these methods on purpose:

Cutting. Take a piece of stem and remove the leaves from its lower half. Plant it about half its length deep in soil mixed with compost, at a slant of about 45 to 60°.

Grafting. Make a slit in a rooted plant A (say, a wild rose) and fit in a piece of stem from plant B (say, a yellow rose). Wrap it until it heals. Plant B now grows on plant A's roots. The same is done with mangoes: a strong tree with sour fruit can carry a twig of a sweet variety.

Layering. Bend a flexible twig (of a lemon plant, for example) down and bury its middle in the soil, still attached to the parent. Roots form in 10 to 15 days. Only then cut it free.

Tissue culture. Tiny pieces from shoot tips are grown in a lab into thousands of healthy little plants. In banana farming this gives plants free of virus disease, and high yields. The Krishi Vigyan Kendras (KVKs), under ICAR, train farmers in modern grafting and other methods.