What observations did mendel make as a result of his experiments with dihybrid crosses?

The allele for one trait independently assorted or segregated of another trait.

Explanation:

When Mendel performed the experiments on the pea plants taking two traits at one time called dihybrid cross he knew that the trait will pass on to the offsprings as monohybrid cross due to law of segregation which stated that gametes segregate independently.

When he performed the dihybrid cross with two traits (two variants of each trait), he found that four combination o traits were formed in the F2 generation in the ratio 9:3:3:1.

When the ratio of each trait was taken into account, he found that traits were passed on in the same fashion as of monohybrid cross that is 3:1. This showed that although both traits were taken simultaneously, both traits were passed on independent of each other or alleles for both the traits assorted independently known as the law of independent assortment.