In a diploid plant species, an F₁ with the genotype Gg Ll Tt is test-crossed to a pure-breeding recessive plant with the genotype gg ll tt. The offspring genotypes are as follows: Genotype Number Gg Ll Tt   621 Gg Ll tt        3 Gg ll Tt     64 Gg ll tt   109 gg Ll Tt   103 gg Ll tt     67 gg ll Tt       7 gg ll tt   626 1600 Explain the meaning of this I value.