Comprehensive evaluation and screening of saline–alkali tolerant Japonica rice accessions during the whole growth stage

Saline–alkali stress is one of the major environmental stresses limiting rice growth, development, and productivity. Evaluation and screening of saline–alkali-tolerant rice accessions is important for enhancing food productivity and sustainable production. Natural saline soils are often not entirely saline or alkaline and exhibit both conditions. In this study, we aimed to analyze the saline–alkali tolerance characteristics and different responses of rice accessions during the whole growth stage under fresh water (FW) or saline water (SW) treatments to saline–alkali paddy soils. Overall, 55 Japonica accessions were comprehensively evaluated and screened by measuring 8 indexes related to saline–alkali tolerance. All 8 indexes were significantly lower (P < 0.05) under SW than under FW. All indexes were positively correlated with each other in different degrees, and the correlation differed between FW and SW. The results of principal component analysis and linear regression analysis revealed 4 key indexes of saline–alkali tolerance, namely, plant height, seed-setting rate, grain yield per spike, and grain yield per plant. A saline–alkali-tolerant accession, Bertone, was screened using comprehensive evaluation. Our study provided a theoretical basis for screening and utilization of saline–alkali tolerant rice during the whole growth stage.