If two alleles of a gene (t1 & t2) are incompletely dominant, then selfing individuals that are heterozygous for these two alleles will produce what phenotypic ratios among the progeny?

1:2:1

Explanation:

If two alleles of a gene are incompletely dominant then selfing between two individuals which are heterozygous for these alleles will produce phenotypic ratio as 1:2:1. In such cases phenotypic and genotypic, both the ratios are same.

For example, if two alleles T1 (dominant) and T2 (recessive) represent a flower color in which homozygous dominant alleles produce red colored flower, heterzogygous alleles produce pink flower and homozygous recessive alleles produce white colored flower then selfing between heterzogygous plants will produce three type of flower colors which are red (T1T1), pink (T1T2) and white (T2T2) in the ratio 1:2:1.

The cross is depicted as under:

Parental                       T1T2  x   T1T2

                                    /       |          |      \

Progeny                T1T1   T1T2   T1T2  T2T2

Here, genotypic ratio is also 1:2:1

Such inheritance is known as incomplete inheritance or blended inheritance.