Insight into morphological and molecular variations across Iranian spinach landraces.

Spinach is salt-tolerant leafy vegetable stemmed from central Asia. It has been well adapted to different climates of Iran. We aimed to study genetic diversity between several landraces as a prerequisite for crop improvement programs using molecular markers including microsatellites (SSRs) and morphological traits. Genetic diversity was studied among 22 spinach landraces using morphological and molecular tools. We developed 17 genic and genomic SSR markers based on the information acquired from NCBI resources. Morphological evaluation indicated high variability for economic traits including leaf color, leaf thickness, leaf wrinkle and seed type, across Iranian landraces. The molecular results exhibited that 12 out of 17 primer pairs successfully amplified genomic DNA with explicit bands. The results verified that genic markers were superior to genomic markers to detect polymorphism and genetic diversity. In this regard, PIC for genomic and genic SSRs was in the range of 0.4616-0.6621 and 0.5188-0.7394, respectively. Polymorphic genic SSRs were identified to be directly and indirectly involved in biotic/abiotic stresses. High degree of polymorphism, which was detected across the landraces by genic SSRs, could assist us to select 11 landraces for the second experiment. The second experiment was designed to evaluate the response of selected landraces to salinity stress. The results confirmed genetic variability among the landraces in terms of salinity tolerance. A highly diverse germplasm of Iranian spinach based on molecular and morphological characteristics along with the tolerance to oxidative stress provides an ample opportunity for plant breeders to select superior genotypes.