Comparison Analysis of Salinity Tolerance and Screening of Salinity Tolerance Indicators in 13 Brassica rapa L. ssp. chinensis Varieties at Seedling Stage

PurposeTo analyze the salinity tolerance of different Brassica rapa L. ssp. chinensis varieties, and screen salinity tolerance indicators.

MethodsThirteen B. rapa L. ssp. chinensis varieties were treated under 0 (control) and 100 mmol/L NaCl treatments in this study, and the 16 morphological and physiological and biochemical indicators of different varieties were determined. A comprehensive evaluation method including principal component, membership functions, cluster and stepwise regression analysis was employed to analyze the salt-tolerant coefficient of each single indicator.

ResultsSix independent comprehensive components by principal component analysis were transformed from 16 single indicators, and the cumulative contribution reached 88.25%. The membership function method was performed to calculate comprehensive salinity tolerance evaluation value (D), which carried out cluster analysis, and one highly salt tolerant, seven salt tolerant, three moderately salt tolerant and two salt sensitive B. rapa L. ssp. chinensis varieties were screened. Then, a mathematical equation for the evaluation of B. rapa L. ssp. chinensis salt tolerance was established through stepwise regression analysis: D′=−0.206+0.632PH+0.275RDW, whose average forecast accuracy was 85.06%. Based on the equation, plant height (PH) and root dry weight (RDW) indexes were screened closely related to the salt tolerance.

ConclusionTezhongshanghaiqing was the high salt tolerant cultivar. Nairesijitianbaicai and Lyulinghuobaicai were the salt sensitive varieties. Root dry weight and plant height could be used to identify the salt resistance of B. rapa L. ssp. chinensis varieties.