西瓜种质资源苗期耐盐性鉴定与综合评价OA

To clarify the differences in salt tolerance among watermelon germplasm resources at the seed-ling stage under combined salt stress,and to screen out elite germplasm with strong salt tolerance.A hy-droponic culture method was adopted in the process during which seedlings of 126 watermelon germplasm resources were treated with a 100 mmol/L mixed salt solution(NaCl∶Na2SO4=1∶1).Thirteen growth-related traits,including plant height,stem diameter,SPAD value,shoot fresh mass,and root fresh mass were measured to calculate the salt tolerance coefficient.A comprehensive evaluation of salt tolerance was performed by combining correlation analysis,principal component analysis,and membership function anal-ysis.The results showed that under combined salt stress,the salt tolerance coefficients of all indicators ex-hibited variations to different degrees,with the coefficient of variation ranging from 10.11%to 77.10%.Principal component analysis was performed on the indicators,converting 13 individual indicators into 3 mutually independent comprehensive indicators with a cumulative contribution rate of 73.72%.The in-dicators with the highest factor loadings were total root surface area,average root diameter,and plant height,with correlation coefficients of 0.937,0.715,and 0.799 respectively,which could serve as the main evaluation indicators for salt tolerance of watermelon at the seedling stage.Based on the comprehensive D value,126 watermelon germplasm resources were classified into 5 categories,including 7 highly salt-tolerant germplasms,32 salt-tolerant germplasms,50 moderately salt-tolerant germplasms,34 salt-sensitive germ-plasms,and 3 highly salt-sensitive germplasms.Seven germplasms with strong salt tolerance were screened out,namely TS74,TS38,ZS19,KS26,ZS30,KS8 and ZS32.Under the same experimental condi-tions,total root surface area,average root diameter and plant height can be used as reference indicators for the identification of salt tolerance in watermelon at the seedling stage.