What was the first generation of offspring in Mendel's experiment called?
For one of his early experiments, Mendel established two pure-breeding lines of peas that produced yellow seeds and green seeds.
He crossed these two varieties by transferring pollen from a plant of yellow variety to one of the green variety and from the green to the yellow variety.
In either case, the results were the same--all the seeds produced by these plants, the F1 generation, were the same yellow color.
Mendel described yellow as being dominant, to green, which was termed recessive.
Source: Illustrated World of Science Encyclopedia