Heritability and Relationship to Yield of Excised‐Leaf Water Retention in Durum Wheat1

Abstract

Previous research indicated that excised‐leaf water retention capability was related to drought resistance in Triticum spp., but no information is available on the heritability of the trait or its relationship to yield under drought conditions. The heritability and relationship to yield of excised‐leaf water retention capability was studied in eight durum wheat(T. turgidum L. var. durum)crosses involving the high retention parent ‘Pelissier’. Fifty random lines from each cross were studied under field conditions in the F4,F8 and F8 generations. Standard‐unit heritabilities of initial and initial minus wilted leaf water concentration were calculated by regressing F4 on F6, and F6 on F8 values. Heritability of initial leaf water concentration ranged from 0.08 to 0.61 in the F4/F6, and from 0.15 to 0.41 in the F6/F8 comparisons. Heritability of initial minus wilted water concentration ranged from 0.11 to 0.49 in the F4/F6 comparisons, and from 0.10 to 0.38 in the F6/F8. Simple correlations between yield and initial minus wilted leaf water concentration tended to be low and nonsignificant. Comparisons of the yields of the 10 fastest and 10 slowest water losers within crosses and years, however, showed significant differences in all but three of 20 cases. In two of the crosses, water retention was yield‐negative in low drought stress environments, but yield‐positive in a high‐stress environment. Retention capability tended to be yield‐positive or yield‐neutral in the other crosses regardless of environment. Further studies, using a broader range of genetics sources of high water retention, are required in order to develop suitable selection strategies for the retention trait.