Kind of trait that seemed to vanish in the offspring produced mendels first expiriment?

In Mendel's first experiment, the trait that seemed to vanish in the offspring was the recessive trait.

Here's why:

* Mendel crossed purebred pea plants with contrasting traits. For example, he crossed a plant with round seeds (dominant trait) with a plant with wrinkled seeds (recessive trait).

* The first generation (F1) all displayed the dominant trait. In the round seed/wrinkled seed example, all F1 plants had round seeds. This led Mendel to believe the recessive trait (wrinkled seeds) had disappeared.

* However, the recessive trait reappeared in the second generation (F2). When Mendel allowed the F1 plants to self-pollinate, approximately 25% of the F2 generation displayed the recessive trait (wrinkled seeds).

This led Mendel to conclude that traits are not blended, but rather are passed on as distinct units, now known as genes. The dominant gene masks the expression of the recessive gene in the F1 generation, but the recessive gene is still present and can reappear in later generations.