Consider a monohybrid cross between a homozygous dominant tall pea plant (TT) and a homozygous recessive dwarf pea plant (tt). What will be the genotype and phenotype of the F1 generation?

The homozygous dominant tall pea plant has genotype TT, and the homozygous recessive dwarf pea plant has genotype tt. The gametes produced by the tall plant will all carry the 'T' allele, and the gametes produced by the dwarf plant will all carry the 't' allele. 

When these are crossed, all offspring in the F1 generation will have the genotype Tt. Since 'T' (tallness) is dominant over 't' (dwarfness), the phenotype of all F1 offspring will be tall.