Evaluation of Oxalate Concentration in the U.S. Spinach Germplasm Collection

The entire USDA spinach ( Spinacia oleracea ) germplasm collection (338 accessions) and 11 commercial cultivars were screened for oxalate concentration. There were significant differences in oxalate concentration among the genotypes evaluated, ranging from 5.3% to 11.6% on a dry weight basis. The low-oxalate genotypes identified in our experiments are all S. oleracea . None of the two S. tetrandra and four S. turkestanica accessions screened had low levels of oxalate. Two accessions from Syria, PI 445782 (cultivar name Shami) and PI 445784 (cultivar name Baladi), consistently had low oxalate concentration. When expressed on a fresh weight basis, oxalate concentration may be affected by the moisture content of the plant. Oxalate concentration had little correlation with leaf types (flat or savoy) and leaf weight per plant. With the genetic variation and sources of low oxalate concentration found, breeding of spinach for a low level of oxalate seems feasible.