A variety of pea plant called Blue Persian produces a tall plant with blue seeds. A second variety of pea plant called Spanish Dwarf produces a short plant with white seed. The two varieties are crossed, and the resulting seeds are collected. All of the seeds are white; and when planted, they produce all tall plants. These tall F₁ plants are allowed to self-fertilize. The results for seed color and plant stature in the F₂ generation are as follows:
     F₂ Plant Phenotype        Number
     Blue seed, tall plant.          97
     White seed, tall plant        270
     Blue seed, short plant        33
     White seed, short plant     100
    TOTAL                                500

What is the expected distribution of phenotypes in the F₂ generation?

Key Concepts

Mendelian Genetics

Mendelian genetics is the study of how traits are inherited through generations, based on the principles established by Gregor Mendel. It includes concepts such as dominant and recessive alleles, which determine the phenotype of an organism. In this case, the tall plant trait and the white seed trait can be analyzed using Mendel's laws of segregation and independent assortment to predict the expected phenotypic ratios in the F₂ generation.

Phenotypic Ratios

Phenotypic ratios refer to the relative frequencies of different phenotypes in a given generation. In the F₂ generation of a dihybrid cross, the expected phenotypic ratio can often be derived from the genotypic ratios. For example, in this scenario, the observed numbers of tall and short plants, as well as blue and white seeds, can be used to calculate the expected ratios based on Mendelian inheritance patterns.

Genotype and Phenotype

The genotype is the genetic makeup of an organism, while the phenotype is the observable physical or biochemical characteristics. In this question, the genotype of the F₁ plants is heterozygous for both traits, leading to a specific phenotypic expression in the F₂ generation. Understanding the relationship between genotype and phenotype is crucial for predicting the outcomes of genetic crosses.