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An F1 hybrid (or filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where it may appear as F1 crossbreed. The term is sometimes written with a subscript, as F1 hybrid.
We start with a plant homozygous for blue kernels and cross it with a plant homozygous for yellow kernels. The offspring that result from this cross are called hybrids and are the F1 generation. When two individuals from the F1 generation are crossed the offspring is called the F2 generation.