Investigating of correlation coefficient and path analysis between phytochemical and pigments traits with dry matter of different ecotypes of mint under salinity stress

Obtaining a high dry matter yield is one of the most important goals of plant physiologists. In this regard, it is necessary to know the effective traits in the production of plant dry matter. Salinity stress is also one of the most important non-biological stresses that limits plant growth and affects the morphological, physiological and biochemical properties of plants. Therefore, in order to understand the relationship between dry matter yield and antioxidant properties, photosynthetic and non-photosynthetic pigments of mint under salinity stress, an experiment was conducted as a factorial split-plot (18 mint ecotypes, including longifolia, pulegium, spicata, rotundifolia, mozafariani and piperita, salinity stress at control, 2.5, 5 and 7.5 dS/m levels and harvest stage at   2 stages), based on a randomized complete block design with four replications. The results showed that salinity stress affected the correlation between dry matter and other studied traits. Also, path analysis at different levels of salinity stress showed that total chlorophyll traits had a very high direct effect on dry matter yield. On the other hand, at a 7.5 dS/m salinity level, the dry matter yield of the plant depended on a greater number of traits compared to lower-salinity stress levels. Also, the correlation between traits in the first and second harvest stages was different. The anthocyanin pigment trait had a positive and significant correlation with dry matter yield at 7.5 dS/m. The indirect role of carotenoid pigment was also evident in severe stress. Based on path analysis, all the studied traits, including non-enzymatic antioxidants and anthocyanin and carotenoid pigments, were strongly dependent on the total chlorophyll trait to affect the dry matter yield.