If T represents the gene for tallness while t represents dwarfness. When a tall (TT) crop is crossed with a dwarf (tt) crop, the resultant crop will be

When a tall (TT) crop is crossed with a dwarf (tt) crop, the resultant crop will be 100% tall, but all of the plants will be heterozygous, meaning they will carry one dominant T allele and one recessive t allele (Tt). This is because the T allele for tallness is dominant over the t allele for dwarfness, so even though the dwarf plant only carries the recessive t allele, the tall plant carries two copies of the dominant T allele. The offspring of this cross, called the F1 generation, will inherit one allele from each parent, resulting in a Tt genotype for all plants. While they will all exhibit the tall phenotype, they will carry the recessive allele for dwarfness and can pass it on to their offspring. If two of these F1 plants are crossed with each other, their offspring (the F2 generation) will show a 3:1 ratio of tall to dwarf plants, with both genotypes (TT, Tt, and tt) present in the offspring.