Final answer:
The crossing of a homozygous dominant tall plant with a homozygous recessive short plant produces all tall offspring in the F1 generation. When these offspring self-pollinate, the F2 generation follows a phenotypic ratio of 3 tall plants to 1 short plant, reflecting the genotypic ratio of 1 homozygous dominant:2 heterozygous:1 homozygous recessive.
Step-by-step explanation:
When a tall plant is crossed with a short plant, the genotypes of the parents are typically one homozygous dominant (TT) for tallness and one homozygous recessive (tt) for shortness. The offspring, in this case, would all be heterozygous (Tt) and thus phenotypically tall, as tallness is the dominant trait.
If we allow these tall offspring (F1 generation) to self-pollinate, the resulting F2 generation would include both tall and short plants.
The genotype of the F1 generation will all be Tt (heterozygous) and when these are crossed, the offspring (F2 generation) will have the genotypes TT, Tt, and tt. The phenotypic ratio observed in the F2 generation will be approximately 3 tall plants : 1 short plant, or in percentages, 75% tall and 25% short as per Mendelian inheritance patterns.
Using the Punnett square, we can predict that the genotypic ratio for a cross between two heterozygous tall pea plants (Tt x Tt) will be 1 TT : 2 Tt : 1 tt.
For a cross between a homozygous recessive dwarf pea plant (tt) and a heterozygous tall pea plant (Tt), the phenotypic ratio of the offspring will be 1 tall : 1 short, displaying Mendel's principles of segregation and dominance.
In conclusion, the presence of short offspring in the F2 generation indicates the recessive allele's skipped generation and reemergence according to Mendelian inheritance, where alleles are segregated and the dominant phenotype is expressed unless both recessive alleles are present.