In sweet pea plants (*Lathyrus odoratus*), purple flower color () is dominant over red flower color (), and long pollen grain () is dominant over round pollen grain (). If a heterozygous dihybrid plant with the genotype is self-pollinated and yields a total of F2 seeds, how many of these seeds are expected to produce plants with the double recessive phenotype of red flowers and round pollen grains?
Answer: 10 seeds
Answer
The expected number of seeds producing plants with red flowers and round pollen grains is 10.
In a dihybrid cross involving two heterozygous parents (), independent assortment results in a 9:3:3:1 phenotypic ratio in the F2 generation. The double recessive phenotype (red flowers and round pollen grains, genotype ) accounts for 1 out of 16 total offspring. Multiplying this fraction (1/16) by the total yield of 160 seeds produces an expected value of 10 seeds.
Step-by-Step Solution
Key Concept
Mendel's Law of Independent Assortment and Dihybrid Phenotypic Ratios