Screening of quinoa (Chenopodium quinoa Willd.) germplasms under high-SAR saline water on the basis of growth, yield, and multivariate analysis.

Increasing soil and underground water salinization with decreasing availability of fresh water has become a potential threat to sustainable crop production in arid and semi-arid areas globally. Introduction and evaluation of salt-tolerant halophytic crops is one of the sustainable ways to preserve productivity in saline ecosystems. This study was aimed to screen quinoa germplasms under high-sodium adsorption ratio (SAR) saline stress. Thirteen quinoa germplasms were evaluated under four levels [best available water (BAW), 8, 16, and 24 dSm^-1] of high-SAR saline water irrigation. The evaluation was carried out based on growth, yield, and ionic content parameters along with statistical tools such as multivariate analysis, salt tolerance indices, and correlation. The results showed that the salinity levels of 16 and 24 dSm^-1 resulted in increase of chlorophyll content relative to BAWand 8 dSm^-1. The germplasm CSQ2 recorded the highest proline content (163.7 mg g^-1 FW) at 24 dSm^-1. Increasing levels of salinity reduced relative water content in plant leaves, and the germplasm CSQ2 showed minimal reduction of 4% at 24 dSm^-1. Na⁺ and K⁺ contents in the plants increased with increasing salinity levels, while the K⁺/Na⁺ ratio decreased. The grain yield of quinoa germplasms ranged between 3.5 and 14.1 g plant^-1. The germplasm EC507740 recorded the highest grain yield (7.0 g plant^-1) followed by CSQ1 and CSQ2 at a maximum stress of 24 dSm^-1. Principal component analysis (PCA) and correlation elucidated that Na⁺ content in plants was negatively correlated with all the studied traits except SPAD, proline content, and K⁺ content. The different salt tolerance indices indicated that the germplasms EC507740, CSQ1, CSQ2, EC507738, and IC411825 were more stable at high-SAR salinity, while PCA showed the germplasms EC507740 and CSQ2 as the most salt-tolerant germplasms.