Drs. Russell and Pedersen are working with a different situation in the corn phosphorous or sorghum feeding value traits they target. Both of these traits show continuous variation among the individuals they have tested. Furthermore, crossing a high parent with a low parent can give an intermediate F1 which when selfed produces mostly intermediate offspring. Along with the average types there will be rare extremes. How rare depends on the number of genes controlling the trait and the relative role environment plays in this trait. This is a typical observation with a quantitative trait, where variation at many genes and variation in environment will influence a trait. A plant breeder is less confident in their ability to predict what they will find among offspring with a quantitative trait. Furthermore, when an extreme type is rare, plant breeders will need to plan to work with large numbers of offspring.