Which one of the following symbols and its representation, used in human pedigree analysis is correct –

ABO blood groups in humans are controlled by the gene I. It has three alleles – I^A, I^B and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur –

The genotype of a plant showing the dominant phenotype can be determined by –

Select the correct statement from the ones given below with respect to dihybrid cross –