Question

In Garden peas, tall vine is dominant and short vine is recessive. If a homozygous tall plant is crossed with a homozygous short plant, what genotypes are possible in the F1 generation?

Answer 1

Tall vine being dominant and short plant being recessive, let's suppose the homozygous tall vine is represented by TT and the homozygous short plant is represented by tt. When these two are crossed with each other, following genotypes are obtained in the F1 generation:
TT x tt
Tt, Tt, Tt, Tt
A heterozygous combination is achieved for all the offspring with tall vine as the phenotype, and the recessive gene for the short plant present in the genotype.

Answer 2

All F1 plants will be heterozygous (Tt) and will be tall.

Step-by-step explanation:

As you may already know, homozygosis are beings that have the same allele. Recessive homozygotes have two recessive alleles (aa) and dominant homozygotes have two dominant alleles (AA). If two homozygous plants are crossed the result of F1 will be entirely from heterozygous plants (Aa). Heterozygotic plants assume the characteristic of the dominant alleles.

Thus, we can conclude that AA x aa will result in 100% of tall heterozygous plants (Aa).