Heterosis in Maize as Measured by K Uptake Properties of Seedling Roots: Pedigree Analyses of Inbreds with High or Low Augmentation Potential 1

The ability of the primary root of maize ( Zea mays L.) seedlings to increase its rate of K + ( 86 Rb) uptake when submerged and aerated, its augmentation potential, is heritable and selectable in early backcross generations. A pedigree analysis was performed using 10 inbreds with either a high or low augmentation potential. The basal K + uptake rate was strongly conserved in S 1 progeny of crosses between inbreds with high or low augmentation potential, whereas the augmentation potentials of the S 1 progeny tended to be non‐conserved or open. The augmentation potential of backcross progeny tended in the direction of the parental inbred augmentation potential, whether high or low. There was some indication that augmentation potential was open in hybrids agronomically selected for yield heterosis.