INHERITANCE OF GLAUCOUSNESS AND EPICUTICULAR WAX IN DURUM-WHEAT

Glaucousness, the waxy bloom on the surface of leaves and other plant parts, is associated with amount of grain yield in wheat (Triticum spp .), and quantity of epicuticular waxes is associated with water loss t hrough the cuticle, wettability by pesticide sprays, and disease susce ptibility. The inheritance of glaucousness and epicuticular wax quanti ty is not well understood in durum wheat (T. turgidum L. var. durum). Crosses were made among diverse glaucous (gl) and nonglaucous (ng) gen otypes, and in some cases, the F1 was backcrossed to each parent. Segr egation for visible glaucousness was observed in the field in the pare ntal, F1, F2, and BC1F1 generations. Epicuticular wax quantity was det ermined gravimetrically in the parental, F1, F2 and BC1F1 generations of the cross 'Hugenot G/Hugenot W' and the parental and F1 generations of six other crosses. With the exception of crosses involving the ng parent Hugenot G, gl by ng crosses indicated that nonglaucousness is c ontrolled by a single, completely dominant gene, as has previously bee n reported. Crosses with Hugenot G showed codominance of glaucousness and nonglaucousness, and the heterozygote was of intermediate glaucous ness. Epicuticular wax quantity of the cross Hugenot G/Hugenot W seeme d to be controlled by the same codominant alleles, and the mean wax qu antities of the parents, F1, F2, and BC1F1 agreed with expectation. Si milarly, wax quantity of the other gl by ng crosses indicated that wax quantity was controlled by either the same gene as visible glaucousne ss or a tightly linked gene.