Studies related to genetic salt tolerance in the cucumber, Cucumis sativus L

Abstract

A yield trial performed on 6 diverse populations of cucumbers was correlated to a previously developed seedling screening technique. Moderate salinity levels (EC = 4.0 dS/m) reduced fruit yields and shoot dry weight as compared to the control treatment (EC = 1.6 dS/m) but did not affect fruit quality. This screening technique was modified slightly and used to screen populations of cucumbers from the world collection of plant introductions of an EC of 9.5 dS/m. P.I. 177361 was selected as a salt tolerant parent, and P.I. 19240 was selected as a salt susceptible parent from the screenings. The results of a genetic study of the family derived from these two parents indicate that salt tolerance in cucumbers at an EC of 9.5 dS/m is controlled by a single major genetic locus with many minor loci contributing to overall phenotypic response. Leaf necrosis occurs in salt-stressed individuals that are homozygous for the recessive allele (sa sa) at the major locus. Narrow sense heritabilities of salt tolerance were estimated for several parameters and found to range from 40.9% to 85.8%. Components of variance and heritabilities indicate that salt tolerance can be improved through selection and recombination within this family. Values for leaf area, stem length, and shoot fresh and dry weights of the F(,1) population were greater than those of the salt tolerant parent.