When humans began growing wild plants in cultivation, they selected the best plants to reproduce. Many of those selected plants were these natural outcrosses because they were superior in some way.
A hybrid plant has some advantages, just like hybrid cars. The main advantage is “hybrid vigor.” A hybrid plant has a wider variety of genes than those produced from closely related plants. The wide variety of genes produces more vigorous individuals.
The main group of plants that are labeled as hybrids are the F-1 hybrids produced from seed. Selected individuals from two unrelated groups are self-pollinated for three or more generations so they are genetically quite uniform. When these two groups are crossed, they produce very uniform progeny in the first — or F-1 — generation because the parents were very uniform. Yet they are hybrids because the parents were quite different from each other. If you grow seeds from this F-1 generation, they are not very uniform. You get extremes from one parent group to the other and everything in between. The one who owns the parents is the only one who can produce the F-1 hybrid.
The most popular method of producing new varieties of ornamental plants currently is by propagation without seeds. Many different crosses are made between promising variable parent plants. The seeds from these crosses are not uniform, because the parents were not bred for generations to become uniform. However, a single plant from a cross may be outstanding in some way and is selected as a new variety. Plants of this one outstanding plant are produced by cuttings or more rapidly from tissue culture. With tissue culture, tissue from the selected plant is grown on agar in a laboratory. Thousands of tiny new plants are then grown into mature plants in greenhouses. The new plants are extremely uniform, because they all came from the same individual plant. They are also vigorous because the parents were unrelated. They are hybrids even though they are not labeled as hybrids.
