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.

If green-seeded strains G₁ and G₃ are crossed, what are the phenotype and the genotype of F₁ progeny? 

Verified step by step guidance

1. Step 1: Analyze the table provided. The F1 phenotype for all crosses between green-seeded strains (G₁, G₂, G₃) and the yellow-seeded strain (Y) is yellow, indicating that the yellow seed trait is dominant over the green seed trait.
2. Step 2: Examine the F2 phenotypes for each strain. For G₁, the F2 ratio is 1/4 green and 3/4 yellow, which suggests a single gene with complete dominance. For G₂, the F2 ratio is 7/16 green and 9/16 yellow, which suggests two genes with epistasis. For G₃, the F2 ratio is 37/64 green and 27/64 yellow, which suggests a more complex genetic interaction involving multiple genes.
3. Step 3: Determine the genetic basis of the green-seeded strains G₁ and G₃. G₁ appears to be controlled by a single gene, while G₃ involves multiple genes. This difference in genetic control will influence the phenotypes and genotypes of the F₁ progeny when G₁ and G₃ are crossed.
4. Step 4: Predict the genotype of the F₁ progeny from the G₁ × G₃ cross. Since G₁ and G₃ have different genetic mechanisms, the F₁ progeny will inherit alleles from both strains. The genotype will likely be heterozygous for the single gene from G₁ and heterozygous for the multiple genes from G₃.
5. Step 5: Predict the phenotype of the F₁ progeny from the G₁ × G₃ cross. Given that yellow is dominant in both strains, the F₁ progeny are expected to be yellow-seeded. However, the exact genetic ratios in the F2 generation will depend on the interaction between the single gene from G₁ and the multiple genes from G₃.

Key Concepts

Phenotype and Genotype

Phenotype refers to the observable traits of an organism, such as seed color in lentils, while genotype refers to the genetic makeup that determines these traits. In this case, the green-seeded strains exhibit a green phenotype, but their underlying genotypes may vary, influencing the offspring's traits when crossed with other strains.

Mendelian Inheritance

Mendelian inheritance describes how traits are passed from parents to offspring through dominant and recessive alleles. In the context of the lentil strains, the yellow seed trait appears dominant over the green seed trait, as all F₁ progeny from the crosses exhibit a yellow phenotype, indicating that yellow is the dominant allele.

F₁ and F₂ Generations

The F₁ generation is the first filial generation resulting from a cross between two parental strains, while the F₂ generation is produced by self-fertilization of the F₁ plants. The different proportions of green and yellow seeds in the F₂ generation provide insights into the inheritance patterns and the potential genotypes of the parental strains involved in the crosses.