Effect of cold stress on biochemical and physiological characteristics in the number of olive cultivars

This study was conducted to investigate the frost status in the 11 commercial cultivars, three newly introduced cultivars and two genotypes of olives. After the occurrence of frost at the Tarom region of Zanjan province in February 2019, three trees from each cultivar were selected. Frost symptoms were recorded based on observational indices. Gas exchange traits (stomatal conductance, transpiration and photosynthesis rate), proline content, pigments and leaf nutrients were measured. Evaluation of frost severity based on observational indices revealed that there was a large difference between cultivars to frost tolerance. Principal component analysis differentiated susceptible cultivars and genotypes to frost. Zard, Grossane, Abou-Satl, Konservolia, Picual and Cornicabra cultivars were grouped as frost tolerant cultivars. Direh, Meshkat, Amin and Koroneiki cultivars were introduced as completely cold sensitive. Among the many evaluated traits for screening olive cultivars and genotypes, proline content and pigment (SPAD index) were identified in discrimination as the most important distinguishing traits of olive cultivars in terms of cold tolerance.