Multivariate Analysis as a Tool for Studying the Effects of Salinity in Different Melon Landraces at Germination Stage

Abstract

Although salt stress affects all growth stages of a plant, seed germination and seedling growth stages are known to be more sensitive for most plant species. The current research was carried out to find the most effective indicators when screening melons for salt tolerance. For this purpose, a factorial experiment as a completely randomized design was performed in order to investigate the effects of salinity (0, 20, 40, 60 and 80 mM NaCl) on seed germination parameters, hydrogen peroxide content, lipid peroxidation and some antioxidant enzymes (guaiacol peroxidase, ascorbate peroxidase and superoxide dismutase) in five Iranian melon landraces and one melon cultivar 'Galia' F1 at early seedling growth stage. The 'Galia' F1 was included for comparison as a salt-tolerant cultivar. The data collected from all salinity treatments across six landraces were used for analysis of variance and principal component analysis (PCA) using SPSS software as well as for obtaining Pearson's correlation coefficients (r) among all physiological parameters. Obtained results indicated that averaged all landraces across all treatments, increased NaCl significantly affected all the parameters measured. In all landraces, salt tolerance index (STI) decreased as the salt concentrations increased. The principal component analysis revealed variations among the traits and determined four main factors that explained 97.53% of the total variance. Simple correlation coefficient analyses showed the existence of significant positive and negative correlations among characteristics. Our study suggests that the salt tolerance index and principal component analysis can be used as accurate and easy indicators when screening melons for salt tolerance.

Selection of sunflower genotypes for salt stress and mechanisms of salt tolerance in contrasting genotypes

“…The combinations of the HCA and PCA have been used to distinguish salt-tolerant cultivars from saltsensitive ones (Sarabi et al, 2016). These analyses were also used to evaluate the drought tolerance level of 49 switchgrass genotypes (Liu et al, 2015).…”

“…In wheat, studies verified that the reduction of Na + transport from root to shoot, Na + sequestration in leaf sheath, lesser Na + accumulation and higher K + /Na + ratio in plant tissues under saline conditions are associated with the genotypic characteristic of salttolerance (Rahnama et al, 2011). These parameters have been used for screening salt-tolerant plants, mainly through multivariate analysis, as principal components analysis (PCA) and hierarchical cluster analysis (HCA), and the identified genotypes may be considered for inclusion in the breeding program and future genetic studies for salttolerance (Sarabi et al, 2016).…”

The response of the sugar beet (Beta vulgaris L.ssp. vulgaris var. altissima Döll) genotypes to heat stress in initial growth stage

“…The potential of multivariate analysis technique such as PCA for the identification of tolerant genotypes to environmental stress has been shown in different crops such as rice (Cha-um et al, 2009), sugarcane (Cha-um et al, 2012, tomato (Juan et al, 2005), peanut (Liu et al, 2012) and soybean (Shelke et al, 2017). PCA identifies the probable grouping and establishment of relationships among variables (Martínez-Calvo et al, 2008;Sarabi et al, 2016). Regards lack of significant relationship between stomatal indices and gas exchange parameters maybe due to small number of samples (McElwain et al, 2016), we did not use stomatal characteristics in PCA.…”

Melon growth-promoting rhizobacteria under saline stress

“…Effects on decreased dry matter, vigor, and height of melon seedlings submitted to saline stress were observed by Sarabi et al (2016). These effects are associated to disturbances in homeostasis and nutrient distribution, which deactivate the transport of electrons from the photosynthetic and respiratory apparatus (Munns & Gilliam, 2015).…”