It tells you what the paragraph is going to be about.
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.
If the two traits are unlinked and the F1-plants are self-fertilized, in the F2 generation plants we expect the 9:3:3:1 ratio of offspring: 9/16 tall plants with spherical seeds. 3/16 tall plants with dented seeds.3/16 short plants with spherical seeds. 1/16 short plants with dented seeds.n a dihybrid cross between plants with tall stems and spherical seeds (both dominant) and plants with short stems and dented seeds, all of the F1-hybrid plants would have both dominant characteristics. The dihybrid cross is SSTT x sstt.