Three strains of green-seeded lentil plants appear to have the same phenotype. The strains are designated G₁, G₂, and G₃. Each green-seeded strain is crossed to a pure-breeding yellow-seeded strain designated Y. The F₁ of each cross are yellow; however, self-fertilization of F₁ plants produces F₂ with different proportions of yellow- and green-seeded plants as shown below.

What proportion of the F₂ will have yellow seeds? Show your work. 

Verified step by step guidance

1. Step 1: Analyze the table provided. The table shows the F1 and F2 phenotypes for three green-seeded lentil strains (G₁, G₂, G₃) crossed with a pure-breeding yellow-seeded strain (Y). The F1 generation is entirely yellow for all crosses, indicating yellow is dominant over green.
2. Step 2: For the F2 generation, examine the proportions of green and yellow seeds for each strain. The proportions are given as fractions: G₁ has 1/4 green and 3/4 yellow, G₂ has 7/16 green and 9/16 yellow, and G₃ has 37/64 green and 27/64 yellow.
3. Step 3: To calculate the proportion of yellow seeds in the F2 generation for each strain, use the fractions provided in the table. For example, for G₁, the proportion of yellow seeds is 3/4.
4. Step 4: If needed, convert the fractions to percentages or decimals for easier comparison. For instance, 3/4 equals 75%, 9/16 equals approximately 56.25%, and 27/64 equals approximately 42.19%.
5. Step 5: Summarize the proportions of yellow seeds for each strain (G₁, G₂, G₃) based on the table data. This will help in understanding the inheritance patterns and dominance relationships between the green and yellow seed traits.

Key Concepts

Mendelian Inheritance

Mendelian inheritance refers to the principles of heredity established by Gregor Mendel, which include the concepts of dominant and recessive traits. In this context, yellow seeds are dominant over green seeds. When a pure-breeding yellow strain is crossed with a green-seeded strain, all F₁ offspring exhibit the dominant yellow phenotype, demonstrating the basic principles of dominance in genetics.

Phenotypic Ratios

Phenotypic ratios describe the relative frequencies of different phenotypes in the offspring of a genetic cross. In the F₂ generation, the ratios of yellow to green seeds can be calculated based on the inheritance patterns observed in the F₁ generation. Understanding these ratios is crucial for predicting the outcomes of genetic crosses and interpreting the results shown in the provided table.

Self-Fertilization

Self-fertilization occurs when an organism fertilizes itself, leading to the production of offspring that may exhibit a variety of phenotypes based on the genetic makeup of the parent. In this scenario, the F₁ plants, which are all yellow, are self-fertilized to produce the F₂ generation, resulting in a mix of yellow and green seeds. This process is essential for understanding the inheritance patterns and calculating the proportions of different phenotypes in the offspring.