Principal component analysis approach for comprehensive screening of salt stress-tolerant tomato germplasm at the seedling stage

Abstract

Salt stress is a major abiotic factor that affects the growth and yield of crops. The present study was carried out to assess the salt tolerance among the Arka Samrat, Arka Rakshak, YVU-1, S-22, YVU-2, and PKM-OP tomato germplasms using principal component analysis (PCA). Different salt (NaCl) concentrations like control, 0.04 M, 0.12 M, and 0.20 M were selected in order to classify them into sensitive and tolerant tomato germplasms based on 13 parameters. A significant variation was observed among the selected tomato germplasms towards salinity tolerance at the seedling stage. Shoot length, root length, fresh weight, and dry weight parameters of the seedlings were decreased linearly with an increase in the external NaCl concentration. Salinization of plants has shown to reduce K⁺ content and increase in the Na⁺ accumulation, Ca²⁺, and Catalase activity. Salt stress also increased electrolyte leakage and reduced relative water content of all germplasms. The maximum parameters were less affected in Arka Rakshak and Arka Samrat compared to the remaining germplasms at higher salt stress. The PCA analysis of 13 morphological and physiological variables indicated that Arka Rakshak and Arka Samrat germplasms were salt-tolerant and PKM-OP was susceptible. Thus PCA analysis results are useful for the identification of resistance and sensitive germplasms at the seedling stage.