In radishes,two incompletely dominant genes control color and shape.Red (R)is dominant over white (r),and heterozygotes are purple.Long (L)is dominant over round (l),and heterozygotes are oval.If a true-breeding long,red radish is crossed with a purple oval radish,give the F1 phenotypes and their percentages.
A) All long red
B) 25% long red, 25% long purple, 25% oval red, 25% oval purple
C) 25% long red, 50% round purple, 25% round white
D) 25% long red, 50% long purple, 25% oval white
E) 25% oval red, 25% oval purple, 50% round purple

Question

Quizplus · Accepted Answer

The true-breeding long, red radish must have the genotype RRLl (since it is crossed with a purple, oval radish which is heterozygous for both traits, indicating the true-breeding radish must contribute the recessive l allele for shape). The purple, oval radish has the genotype RrLl. The F1 generation will show a 1:1:1:1 phenotypic ratio due to the independent assortment and incomplete dominance of both traits, resulting in 25% long red, 25% long purple, 25% oval red, and 25% oval purple.

In Radishes,two Incompletely Dominant Genes Control Color and Shape