In the F_(2) generation of Mendel's crosses, all plants had the dominant trait. half of the plants had the dominant allele. all plants had both the dominant and recessive alleles one in four plants had two alleles for the recessive trait.

In the F2 generation of Mendel's crosses, one in four plants had two alleles for the recessive trait. This is because when Mendel crossed two heterozygous plants (F1 generation), the resulting genotypic ratio in the F2 generation was 1:2:1 (one homozygous dominant, two heterozygous, and one homozygous recessive). Therefore, one out of four plants exhibited the recessive phenotype, having two alleles for the recessive trait.