A genetic cross between two F1 hybrid pea plants for spherical seeds would yield 100% spherical seeded plants in the F2 generation.
This can be determined by using a Punnett square. A Punnett square is a tool used to predict the probability of different genotypes (combinations of alleles) in the offspring of a genetic cross.
In this case, the spherical seed allele (S) is dominant over the dented seed allele (s). So, the F1 hybrid pea plants will have the genotype Ss, meaning that they carry one dominant allele for spherical seeds and one recessive allele for dented seeds.
When these F1 plants are crossed, we can use the Punnett square to predict the possible genotypes of the offspring.
In this Punnett square, the F1 plants are represented by the letters S and s in the top and leftmost rows. The letters in the boxes represent the possible genotypes of the offspring. Each box represents the possible genotype of the offspring that results from the combination of the alleles from the parents in that particular row and column.
As we can see, in the F2 generation, the offspring have a 100% chance of having the genotype Ss, which corresponds to the dominant allele for spherical seeds. Therefore, 100% of the offspring will have spherical seeds.