Q.Briefly describe various steps involved in plant breeding.

Plant breeding is a systematic, multi-step process aimed at creating new and improved crop varieties. The important steps involved are:

• 1. Collection of variability (germplasm collection): Genetic variability is the basis of any breeding programme. All the different wild species, varieties and cultivated types of a crop plant, along with their wild relatives, are collected and preserved as germplasm — the entire collection of plants/seeds with all the diverse alleles for a given crop. This is essential because a plant breeder can only select desirable traits that exist within this available pool of variability.
• 2. Evaluation and selection of parents: The collected germplasm is evaluated to identify plants with desirable combinations of characters (e.g., disease resistance, high yield, good quality). Pure lines are prepared where necessary, and plants with the desired traits are selected to be used as parents for hybridisation.
• 3. Cross-hybridisation among the selected parents: The selected parents are cross-bred (hybridised) to combine desirable characters present in two different plants/varieties into a single plant. This is a laborious process — pollen from one parent has to be collected and used to pollinate the emasculated (anthers removed) flower of the other parent to ensure only the desired cross takes place, guarding against undesired pollination.
• 4. Selection and testing of superior recombinants: Among the progeny produced from hybridisation, plants with the desired combination of characters (superior recombinants) are selected using appropriate selection procedures. These selected plants are then self-pollinated for several generations until they achieve uniformity/homozygosity, so that the characters are not lost in subsequent generations. …

Present the five steps in strict order (germplasm collection → parent evaluation/selection → hybridisation → selection/testing of recombinants → field testing …

• Jumbling the order of steps, e.g., placing hybridisation before evaluation/selection of parents.
• Skipping the self-pollination-for-uniformity step needed after selecting superior recombinants, or the multi-season/multi-location field-testing step before release. …