Final answer:
Hybrid vigor is an alternative term for heterosis, the advantageous trait where hybrids show superior qualities in comparison to their inbred counterparts. This is separate from incomplete dominance, where the hybrid phenotype is intermediate between its parents, such as pink flowers in snapdragons from red and white parents. Plant breeders have used hybrid vigor to create more robust and productive crop varieties.
Step-by-step explanation:
An alternative term for heterosis, which is the observed superiority in performance of hybrids compared to their inbred parents, is hybrid vigor. This concept is often seen in the context of agricultural practices, where hybrid seeds are produced to enhance crop yields. Inbreeding depression, which refers to the reduced biological vigor resulting from inbreeding, is alleviated by hybridization, leading to hybrids that outperform inbred lines.
In the example of the snapdragon, Antirrhinum majus, the cross between homozygous red and white flowered plants results in offspring with pink flowers, demonstrating incomplete dominance. This means that the phenotype of the hybrid is intermediate between the two parents. It's important to note that hybrid vigor is distinct from incomplete dominance; while the former refers to the general enhanced performance of hybrids, the latter describes a specific pattern of inheritance.
Early 20th-century plant breeders capitalized on hybrid vigor to develop robust hybrid crops like corn, which was one of the first species to be commercially exploited for this trait.