why crops improvement is necessary?
Answers
CROP IMPROVEMENT. CROP IMPROVEMENT. Crop improvement refers to the genetic alteration of plants to satisfy human needs. In prehistory, human forebears in various parts of the world brought into cultivation a few hundred species from the hundreds of thousands available.
The advantage of traditional breeding is that you don't need to know which gene variations influence which traits. The disadvantages are that it can take a lot of time (often many years) and effort, and it may not produce the desired result.
The general approach of traditional breeding is to combine certain traits from two parents into one offspring. For example, you might cross a domesticated plant with a wild relative that is resistant to a certain disease. Some of the offspring may be disease resistant, but they will also lack many of the useful traits of the domesticated parent. Getting the traits back requires "back-crossing," or breeding the offspring with the domesticated plant, for many generations. It may take additional generations to make sure the resulting plants "breed true"—that is, they consistently make offspring like themselves.
Some traits are tricky to manipulate by traditional breeding. For example, drought resistance is influenced by variations in multiple genes, each of which may have a very small effect. Making a plant drought resistant requires generating offspring with certain gene combinations that may form only rarely.