The cross of a pea plant with round seeds (RR) with another pea plant with wrinkled seeds (rr) is shown as under :
P RR x rr
F1 Rr Rr Rr Rr
It is clear from the cross above, all the 4 probable progenies in filial 1 (F1) generation will be heterozygous with Rr genotype. Not even a single progeny will have homozygous recessive genotype which is responsible for producing wrinkled seeds. Also, even though the genotype of the progenies will be Rr not RR yet phenotypically they all will have round seeds i.e. they will show dominant trait. The reason behind it is that one of the alleles R which is responsible for dominant trait will mask the expression of recessive allele r. So, wrinkled phenotype which is a recessive trait will not be observed in any of the progenies.
