Polygenic inheritance in plants is the type of inheritance in which a single trait is controlled by two or more genes, often called polygenes.
Each of these genes has a small additive effect on the overall expression of the trait. This means that no single gene completely determines the trait — instead, the combined effect of several genes influences the final result.
Because many genes are involved, polygenic traits show continuous variation rather than distinct categories. Examples include height, yield, seed weight, or leaf size in plants — traits that can vary gradually from small to large or short to tall.
For example:
- In wheat, kernel color is determined by several genes, and the more dominant alleles a plant has, the darker the kernel color will be.
- In maize, plant height depends on the combined effects of many genes affecting growth.
In summary:
Polygenic inheritance = multiple genes + additive effects = continuous variation in traits.