The spinach (Spinacia oleracea L.) is an important crop in most regions of the world which is native to Iran. For evaluation of its biological diversity, sixteen landraces collected from different geographical regions of Iran and some quantitative traits remeasured as leaf length (LL), leaf width (LW), petiole length (PL), petiole diameter (PD), leaf area (LA), leaf numbers in flowering (LN), days to flowering (DF), female plants percent (FP), fresh yield (FY) and dry yield (DY). The landraces showed high variability in the morphological characteristics according to analysis of variance. Accession Arak had the high amounts of dry yield, fresh yield, leaf area and leaf numbers and regarding the importance of yield and low properties of petiole length and diameter, accession Arak followed by accessions Karaj and Birjand were identified Dendrogram analysis of a cluster constructed from genotypic distance matrices showed that sixteen landraces could be grouped into three clusters. The number of clusters was confirmed by multivariate analysis using the Wilks lambda statistic test of variance. Accessions Arak, Karaj, Rahnan, Birjand and Sirjan were grouped in cluster-I, accessions Ardestan, Zabol, Bojnord, Esfahan and Shiraz were grouped in cluster-II, accessions Brojerd, Drood, Langrood, Maragheh, Salmas and Tabriz were grouped in clusterIII. The accessions the cluster-I were useful for yield performance while the accessions the cluster-III were useful for improving the quality of spinach.
