Inheritance of stem solidness in eight durum wheat crosses

Yield loss from sawfly (Cephus cinctus Norton) can be prevented by growing solid-stemmed wheat. No solid-stemmed durum cultivars (Triticum turgidumL. var. durum) are registered in Canada, even though solid-stemmed lines are available. Understanding the inheritance of stem solidness in such lines would be useful to breeders. Eight crosses were made between solid-stemmed and hollow-stemmed durums: Trinakria/DT369, Trinakria/DT367, Hugenot G/DT369, Hugenot W/DT369, 8678-1048A/Hugenot W, 8678-1048A/Hugen ot G, Kamilaroi/Hugenot G, and W9262-260D3/Kofa. Trinakria, Hugenot G, Hugenot W and W9262-260D3 are solid-stemmed and the other parents are hollow stemmed. Stem solidness was measured in field trials. The F 1 were solid-stemmed, and the F 2 of five of the seven crosses were not significantly different (P > 0.05) from a three solid-stemmed to one hollow-stemmed segregation ratio. The backcross of the solid-stemmed parents with the F 1 was 100% solid-stemmed, and the backcross of the hollow-stemmed parents with the F 1 was not significantly different (P > 0.05) from an expected one solid-stemmed to one hollow-stemmed segregation ratio. The F 1 derived doubled haploids did not differ significantly (P > 0.05) from an expected one solid-stemmed to one hollow-stemmed segregation ratio. The expression of stem solidness fit the expected segregation ratios for a single dominant gene model in most of the crosses, which suggests that stem solidness in the four durums evaluated is controlled by a single dominant gene. Key words: Inheritance, sawfly, solid-stemmed, Triticum turgidum L. var. durum