Inheritance of yellow pigment concentration in seven durum wheat crosses

Yellow pigment concentration of the endosperm due to the presence of xanthophyll and other related compounds is an important processing quality characteristic in durum wheat (Triticum turgidum L. var. durum). There is also interest in plant pigments for health reasons because lutein, a major component of durum grain pigment, may. play a role in prevention of age-related macular degeneration. Selection for pigment concentration of durum wheat is thus an important breeding objective. Clarification of environmental effects and the mode of inheritance would aid planning of crosses and selection strategies to improve pigment concentration. This study evaluated seven durum wheat crosses of high by low pigment concentration parents in five field trials grown at two or more locations for 2 or more years in western Canada. Pigment concentration varied with environment. A portion of the variability could be ascribed to environmental effects on kernel weight, which tended to be negatively correlated with pigment concentration in some crosses and years (r = 0.08 to -0.49), but was not consistent. Inheritance of pigment concentration was multigenic as evidenced by bi-directional transgressive segregation and estimates of the number of effective factors controlling the trait. The number of effective factors varied with cross and environment, ranging from 3 to 27. Heritability of pigment concentration was high when measured in replicated, multi-location, multi-year trials, and ranged from 0.88 to 0.95, but lower (0.34) in an unreplicated segregating cross. The complex inheritance of pigment concentration means that other genetic tools, such as DNA markers, will be required to improve choice of parents for crossing and selection strategies in breeding programs.