Evaluation of Iranian spinach populations by the synchronic study of morphological ‎traits, photosynthetic indices and oxalate accumulation

Spinach, due to high nutrition and economic value, highly regarded by the breeders. In this research, 40 populations belonging to three species of Spinacia oleracea, S. turkestanica, and S. tetrandra from most parts of Iran, along with a wild population from Afghanistan and two commercial cultivars Viroflay and Baby spinach, formed the studied germplasm. Thirty-three traits were classified under three groups of morphological, physiological, and biochemical. The results showed that the germplasm had a rich genetic structural diversity for the studied traits. The average coefficient variance of the studied traits was 29.8%. Oxalate accumulation showed a significant difference in the studied populations. The minimum oxalate accumulation was observed in the Karaj population of S. oleracea with 682 mg per 100 g FW. The maximum accumulation was found in the Bazangan population, the wild species of S. turkestanica, with 2902 mg per 100 g FW. The cluster analysis results put the two wild species populations in the same group and separated from the other ones. The coefficients of correlation were ranged from -0.83 to 0.99. In total, 43.1% out of all trait's interactions had a significant correlation (α = 0.01 or 0.05). The correlation results showed that the plant with a higher performance index had more freshness after harvesting. Also, the blistering was the only trait of among of all that had a significant negative correlation with oxalate accumulation.