Final answer:
In a dihybrid cross of corn, the F1 generation consists of heterozygous RrYy plants. Crossing two F1 generation plants yields an F2 generation with a phenotypic ratio of 9:3:3:1 observed by Mendel, which is calculated using a Punnett square.
Step-by-step explanation:
Dihybrid Cross in Corn
The student's question pertains to a dihybrid cross, which is a method used in genetics to study the inheritance of two different traits or genes simultaneously. In the F1 generation of a dihybrid cross involving corn, the parents are typically heterozygous for both traits, with genotypes RrYy. This denotes heterozygosity for both seed color (Rr) and seed texture (Yy), where 'R' represents dominant purple, 'r' for recessive yellow, 'Su' for dominant smooth, and 'su' for recessive wrinkled. The F2 generation results from crossing two F1 individuals, and Mendel's observations revealed that the ratio of phenotypes obtained is 9:3:3:1. This means in the F2 generation, 9/16 will exhibit purple smooth seeds, 3/16 yellow smooth seeds, 3/16 purple wrinkled seeds, and 1/16 yellow wrinkled seeds.
Punnett squares can be used to predict the genotypic and phenotypic outcomes of genetic crosses. For the F1 generation cross RrYy x RrYy, the Punnett square would depict all the potential combinations of alleles from the parental gametes. This results in the phenotypic ratio of 9:3:3:1, which represents different combinations of dominant and recessive traits.