Virus free plants can be formed by

Assertion : In case of vegetatively propagated crops, pure-line selection is not required.

Reason : Hybrid vigour is mostly used in vegetatively propagated plants.

Micropropagation is

Assertion : Use of fertilizers greatly enhances crop productivity.

Reason : Irrigation is very important in increasing crop productivity.

Which one of the following methods is commonly used to maintain the genetic traits of a given plant