Spinach (Spinacia oleracea L.) accumulates large amounts of oxalate, which reacts with calcium, inhibiting its absorption and forming urinary stones in humans. In this study, low-oxalate spinach mutant was induced through chemical mutation. Seeds of the gynomonoecious line of ‘Shin-Nippon’ were treated with 50 mM ethyl methane sulphonate (EMS) for 6 h. Self-fertilized M2 seeds were harvested from M1 plants individually. Total oxalate (water soluble and insoluble) concentrations of M2 plants were measured, and four low-oxalate plants were selected. Self-fertilized M3 seeds were harvested from these M2 plants individually. In the progenies of three M2 plants, oxalate concentration ranged from 9 to 19 mg·g−1FW; there were no low-oxalate plants; however, in the progeny of one M2 plant, five of eight plants had low oxalate; their concentration were lower than 2 mg·g−1FW. Self-fertilized M4 seeds were harvested from low-oxalate M3 plants individually. The progenies of low-oxalate M3 plants, named low-oxalate lines, were grown and compared with the original ‘Shin-Nippon’ and gynomonoecius line (wild types). Leaves of low-oxalate lines were slightly smaller and thinner than wild types, whereas the leaf number and color were similar. Oxalate concentrations of leaves in low-oxalate lines strongly decreased; one third to one sixth of those in wild types. Nitrate concentrations did not decrease in low-oxalate lines.
2009 by Japanese Society for Horticultural Science