Which of the following statements are incorrect?

(i) Genes which code for a pair of contrasting traits are known as alleles, i.e., they are slightly different forms of the same gene.

(ii) T is used for the tall trait and t for the ‘dwarf, and T and t are alleles of each other.

(iii) Allele may be homozygous, TT and tt, or heterozygous Tt.

(iv) To determine the genotype of a tall plant at F 2 , Mendel crossed the tall plant from F 2 with a dwarf plant. This is called as test cross.

(v) In a typical test cross an organism showing a dominant phenotype is crossed with the any parent instead of self-crossing.

(vi) Based on his observations on monohybrid crosses Mendel proposed three general rules.