Genetic variation and selection of fine families of Ulmus pumila L. in seedling stage under salinealkali stress

Eight ploted family seedlings of Ulmus pumila L. were treated by mixture of Na2CO3 and NaHCO3 for 6 times, and the stress was ranging from concentrations (salinealkali content in soil) of 0.15% to 0.95% gradually. Injury characteristics of 8 families under salinealkali stress were investigated. Growth traits were measured before the salinealkali treatment and after the end of experiment. Results showed that serious injury ratio, death ratio and total injury ratio increased gradually as the stress strengthened, but light injury ratio changed slightly. Analysis of variance showed that leaf injury characteristic indices but light injury rate had significant difference between different salinealkali concentrations and families, but the contribution of induce variation of concentration was greater than that of families. Based on injury characteristics and growth traits, the results were similar. The families of 2 and 7 were assessed to be salinealkali tolerance germplasm; families 4, 1, 6, 5 were salinealkali sensitivity germplasm, and the families of 3, 8 were moderatetolerance germplasm.