Comprehensive evaluation of quinoa seed responses to drought and salt stress during germination

With the development of quinoa industry, the responses of quinoa seeds to drought and salt stress at the germination stage have been gaining attention. In this paper, the drought resistance and salt tolerance of five quinoa cultivars (lines) (including 'South Africa No. 2' 'Longli No. 1' 'Longli No. 4', HTH-y605 and HTH-01) during germination were studied using indoor PEG-6000 simulated drought stress and NaCl simulated salt stress treatments. Germination rate and potential, seedlings length and fresh weight were determined. Principal component analysis was used to evaluate the drought resistance and salt resistance of quinoa, and the main evaluation indices for drought resistance and salt tolerance were identified. Results showed that different stresses had little effect on germination rate, germination potential, and germination index, but that they significantly inhibited seedling vigor index. The eight measured indices were classified into two component factors by principal component analysis, and the largest components related to seedling relative length and relative germination rate load, which could be used as main identification indices for quinoa drought resistance during the germination stage. The order of drought resistance of the tested cultivars (lines) was as follows: 'South Africa No. 2' > HTH-01 > 'Longli No. 4' > 'Longli No. 1' > HTH-y605. In terms of salt resistance, principal component analysis separated the eight indicators into three composition factors relating to the seedling relative length, relative germination rate, and relative germination index, respectively. The largest component factors can be used to identify quinoa cultivars (lines) with high salt resistance during germination. The order of salt resistance of the tested cultivars (lines) was as follows: HTH-01 > HTH-y605 > 'Longli No. 4' > 'Longli No. 1' > 'South Africa No. 2'. The drought resistance and salt tolerances of quinoa cultivars (lines) were sorted by the score function of the comprehensive factor of principal component analysis, and the results showed that 'Longli No. 4' had the strongest drought resistance, but the worst salt resistance. HTH-y605 had the strongest drought resistance as well as the strongest salt resistance. Correlation analysis showed that there was no significant correlation between drought resistance and salt tolerances of different quinoa cultivars (lines) at the germination stage. It was found that different quinoa cultivars (lines) were genetically diverse in terms of drought resistance and salt tolerance. The conclusion of this study provides a reference for research on the stress mechanisms of quinoa and for selective breeding of varieties, and provides theoretical and data to support the development of current low and medium yield fields.