Comparison of soil and genotypic effects on calcium concentration of snap bean pods

Soils were fertilized with gypsum (CaSO4 . 2H(2)O) at rates up to 4 t . ha(-1), and Ca2+ concentrations in pods of 12 snap bean (Phaseolus vulgaris L.) cultivars were determined, with the intention of improving snap beans as a source of Ca2+ for human nutrition. The addition of gypsum to the soil did not affect the Ca2+ concentration of pods, even though Ca2+ in the soil solution increased from 4 to 15 mmol . L(-1). Calcium concentrations of pods of the various snap bean cultivars ranged from 4.1 to 5.7 mg . g(-1) dry mass. 'Top Crop', 'Astrel', 'Tenderlake', and 'True Blue' had the highest Ca2+ concentration in the pods and 'Labrador' and 'Roma II' had the lowest. The results suggest that factors other than Ca2+ supply influenced the Ca2+ concentration of the snap bean pod. Therefore, increased Ca2+ concentration of pods may be better achieved through breeding and selection rather than Ca2+ fertilization when Ca2+ levels in soil are sufficient.