Plant Breeding

Since the dawn of civilization, man has tamed the wild to meet his ends; not just animals but plants as well. And practically that was the point of time from where the practice of breeding started. Plant breeding is the purposeful manipulation of qualities in plants to create new varieties with a set of desired characteristics. Breeding has been extensively applied to food crops to develop crops with a better agricultural application. The objective of plant breeding varies from increased yield to enhanced nutritional profile, resistance against plant diseases, insects, and pests that attack plants and decrease productivity.

Plant Breeding Methods

The plant breeding methods have undergone multiple amendments since it started 9000 – 11000 years ago. The modern method of breeding is carried out in the following steps:-

  • Collection of variability – Variability forms the root of all breeding practices. The first step involves the collection of plants or seeds for all possible alleles for all genes in a given crop, which is known as germplasm. This collection even involves wild varieties and relatives of the cultivated species.
  • Evaluation and selection of parents – The germplasm is evaluated for selection of parent plants with desired characteristics. The combination of these characteristics is expected in the hybrid progeny. For example, a plant crop with high protein content can be selected to be crossed with a plant with higher disease resistance.
Plant breeding

Plant breeding: Tissue Culture

  • Cross-hybridization among selected parents – In the third step, the parents are cross-hybridized to develop pure lines of progenies. This is a tedious and time-consuming practice carried out in the conventional fashion of introducing pollen from one plant to the stigma of the other. Despite the labor involved, only one or two progenies in a few hundred show the desired combination of characteristics.
  • Selection and testing of superior recombinants – The developed progenies are then evaluated and those with the desired combination of characteristics are self-pollinated to attain homozygosity.
  • Testing, release, and commercialization of new cultivars – The new lines are grown in research fields where they are tested for their agronomic traits of quality, yield, resistance to diseases, etc. This is followed by cultivation of these crops in farmers’ fields at different locations in the country which represent the different agroclimatic zones. With successful results, the crops are released commercially for public consumption.

Learn more about the objectives of plant breeding, tissue culture and how they are conducted at Byju’s.

Practise This Question

With regards to the assertion and reason, choose the correct option.
Assertion: In case of vegetatively propagated crops, pure line selection is not required.
Reason: Hybrid vigour is a property of vegetatively propagated plants.