How many different phenotypes and genotypes are obtained in the F2 generation of Mendel’s dihybrid cross?
4 phenotypes and 9 genotypes
Mendel considered two traits- seed colour and type for his dihybrid cross. He crossed two pure-bred varieties round yellow seeded plants (RRYY) with the (rryy) wrinkled green seeded plants, and self-fertilized the F1 hybrids (RrYy). The Punnett square here shows the different combinations of F2 progeny obtained.
The F2 progeny of Mendel’s dihybrid cross exhibit four different phenotypes: round yellow, round green, wrinkled yellow and wrinkled green.
And 9 different genotypes:
Thus 4+2+2+1 = 9 genotypes
Of the four phenotypes, two are parental types and two are recombinants. Out of the 16 genotypes, there are 9 different types.