How to develop from three parents a new variety of a self-fertilizing crop?

Summary

The aim is to combine the genes for attractive levels of expression for three different characters. These genes occur in three different lines of an autogamous crop. The 12 breeding procedures evaluated comprise each combination of three different crossing programs with selection among the obtained F2 plants (or not) and with random mating among the (selected) plants (or not). For independent segregating loci random mating has no effect or only an unrewarding small effect, depending on the crossing program.

In case of selection the crossing programs differing from the conventional scheme for a three-way cross deserve attention. With selection in F2 the frequency of plants with the desired genotype is increased by 20% with different crossing programs.