See 'Gene_Class : Spelt' for comments regarding the Q, C, and S1 genotypes of hexaploid wheats and the durum and carthlicum groups.
Sphaerococcum-like tetraploid wheats have been reported (93, 324, 908, 910), but comparisons between them, or with s2, have not been made. Whereas Schmidt & Johnson (907) reported a single recessive factor controlling the sphaerococcum character in tetraploid wheat, Joppa (442), using the same stock, found that two recessive genes were necessary to produce this phenotype.
Wheat Gene Catalog Reference
Schmidt JW and Johnson VA (1966) Inheritance of the Sphaerococcum effect in tetraploid wheat. Wheat Information Service 22:5-6.
Bozzini A (1965) Sphaerococcoid, a radiation-induced mutation in Triticum durum Desf. Use of Induced Mutations in Plant Breeding. Proceedings of FAO/IEAE Meeting, Rome, Italy 375-383.
Schmidt JW and Johnson VA (1963) A sphaerococcum-like tetraploid wheat. Crop Science 3:98-99.
Schmidt JW et al. (1963) Inheritance of an incompletely dominant character in common wheat simulating Triticum sphaerococcum. Crop Science 3:261-264.