phenotypes, that are phenotypically different from the original P generation, each independent gene acts exactly as it would in a monohybrid cross. The new F2 phenotypic ratio for both characters combined is simply the product of two separate monohybrid crosses. The new phenotypes (i.e. phenotypes different than any in the P generation) that should occur in any cross of two or more characters, called a multihybrid cross, is determined based on the principle that the chance of independent events occurring together equals the product of the chances of each event occurring separately. In the above example, the number of offspring in the F2 generation with both green and constricted pods is determined by multiplying the expected percentage of green pods in the F2 generation of a monohybrid cross (3/4) by the expected percentage of constricted pods in the F2 generation of a monohybrid cross (1/4). Multiplying 3/4 by 1/4 equals 3/16, and, therefore, there would be 3 green/constricted pod F2 individuals out of 16 total possibilities in a dihybrid cross between green/inflated pod individuals and yellow/constricted pod individuals.
All multihybrid crosses follow this principle no matter how many characters are considered as long as all the characters have independent genes. If a third character, one for stem length in which long-stemmed pea plants show the dominant expression and short-stemmed plants show the recessive expression, is added to the original P generation cross in the example above, the number of F2 generation offspring with green/constricted pods and short stems, for instance, equals 3/4 x 1/4 x 1/4, the
