Question

assume you are investigating the inheritance of stem length in pea plants. you cross - pollinate a short - stemmed plant with a long - stemmed plant. all of the offspring have long stems. then, you let the offspring self - pollinate. describe the stem lengths you would expect to find in the second generation of offspring.
a the f2 would have 50% long - stemmed plants and 50% short - stemmed plants.
b the f2 would have 25% long - stemmed plants and 75% short - stemmed plants.
c the f2 would have 75% long - stemmed plants and 25% short - stemmed plants.
d none of the above

Explanation:

Step1: Determine dominant and recessive traits

When a short - stemmed plant is crossed with a long - stemmed plant and all \(F_1\) offspring have long stems, long stem (\(L\)) is dominant and short stem (\(l\)) is recessive. The \(F_1\) generation has a genotype of \(Ll\) (heterozygous).

Step2: Analyze \(F_1\) self - pollination

When \(Ll\times Ll\), using the Punnett square:

Gametes of Parent 1	Gametes of Parent 2
\(L\)	\(LL\) (long - stemmed)	\(Ll\) (long - stemmed)
\(l\)	\(Ll\) (long - stemmed)	\(ll\) (short - stemmed)

The genotypes of \(F_2\) are \(LL:Ll:ll = 1:2:1\). The phenotypic ratio (based on dominant - recessive relationship) is long - stemmed (\(LL + Ll\)) : short - stemmed (\(ll\)) \(=3:1\) or \(75\%\) long - stemmed and \(25\%\) short - stemmed.

Answer:

C. The F2 would have 75% long - stemmed plants and 25% short - stemmed plants.