You are breeding a type of tulip. You begin with a pure-breeding line of yellow

Question

You are breeding a type of tulip. You begin with a pure-breeding line of yellow tulip and a pure-breeding line of blue tulip When the yellow tulip is crossed to the blue tulip, all of the progeny are yellow When these yellow progeny are crossed to each other, you count 116 yellow tulips and 44 blue tulips. You decide to do a self-cross with some of the tulips in that final batch. Which of these terms best describes the genotype of the following flowers? CFrom the last batch of tulips, you take one of the yellow tulips. In a self-cross, the A ascus resulting progeny have both yellow and blue tulips B heterozygous C homozygous recessive D bivalent E. homozygous dominant F propositus cross, the resulting progeny yield only blue tulips. From that last batch of tulips, you take a different one of the yellow tulips. In a self cross, the resulting progeny are only yellow tulips

Explanation / Answer

The first blue and yellow tulips were pure-breeding and hence homozygous. Their cross yielded more yellow tulips than blue ones so we can safely assume that yellow is dominant over blue. This is because you need two copies of the recessive allele to show the recessive trait.
Now Yellow will be represented as TT, Tt, tT.
while Blue will be represented as tt only.
This batch of tulips formed as Yellows and Blues, wherein the Yellows might be homozygous (that is TT) or heterozygous (that is Tt). All blues here will be homozygous recessive (that is tt)
From the last batch of tulips, you take one of the yellow tulips. In a self-cross, the resulting progeny have both yellow and blue tulips: B. heterozygous (one trait self-cross showing more than one trait is only possible if parent is heterozygous)
From the last batch of tulips, you take a different one of the blue tulips. In a self-cross, the resulting progeny yields only blue tulips: C. Homozygous recessive (since all blue recessive tulips are produced, hence pure-breeding)
From the last batch of tulips, you take a different one of the yellow tulips. In a self-cross, the resulting progeny are only yellow tips: E. Homozygous dominant (since all yellow dominant tulips are produced, hence pure-breeding)

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