Variability and inheritance of sulfate uptake efficiency and ATP-sulfurylase activity in maize

Sulfate uptake efficiency of roots and ATP-sulfurylase activity in leaves and in roots were evaluated in maize (Zea mays L.) inbreds W75, 65B, 103B, and in the diallel set of F1 hybrids, in order to assay the variability and the inheritance of the two characters. The correlation at the level of genetic regulation between the uptake and the first step of sulfate metabolism was also determined. Wide genetic differences were seen in the uptake efficiency and in enzyme activity. These traits demonstrated a close correlation and a high level of heterosis. The kinetics of sulfate uptake was also affected by crossing; Vmax followed the same pattern as uptake efficiency, while Km, with the exception of the 103B ✕ 65B cross, showed a low level of heterosis.