Mendel’s most important discovery was that the F₁ progeny of a cross between plants with different traits did not breed true. In the F₂ generation, produced by allowing the F₁ flowers to undergo self-fertilization, the recessive trait reappeared (Fig. 16.6). Not only did the recessive trait reappear, it reappeared in a definite numerical proportion. Among a large number of F₂ progeny, Mendel found that the dominant:recessive ratio was very close to 3:1. The results he observed among the F₂ progeny for each of the seven pairs of traits are given in Table 16.1. Across experiments for all seven traits, the ratio of dominant:recessive F₂ offspring was 14,949:5010. Although there is variation from one experiment to the next, the overall ratio of 14,949:5010 equals 2.98:1, which is a very close approximation to 3:1.