According to Mendel's experiments described in the textbook, when F1 hybrid tall plants (genotype Tt) are self-pollinated (), the resulting F2 generation shows a phenotypic ratio of 3 Tall : 1 Dwarf . This segregation of alleles occurs because both parents are heterozygous (Tt), producing gametes carrying 'T' and 't' in equal proportions . A cross of would produce only tall plants, and would produce a 1:1 ratio .