Inheritance and Association of Subcrown‐Internode Length with Coleoptile and Culm Length in a Winter Wheat Cross1

The inheritance of crown depth was determined by measurement of subcrown‐internode length in a winter wheat ( Triticum aestivum L.) cross between the semidwarf selection C.I. 13253 (‘Norin lO’/Brevor 14) and the standard height cultivar ‘Brevor.’ Cultivars and selections that form deep crowns have been reported to show less winter injury. Broad sense heritability estimates for subcrown‐internode length ranged from 38.4 to 49.7%, and F 4 lines of the cross followed a discontinuous segregation pattern. Subcrown‐internode length and coleoptile length were correlated closely (r = 0.79), which suggested that the two traits are governed by closely linked genes or are related pleiotropically. Similarly, subcrowninternode length closely correlated with culm length (r = 0.77). The growth mechanisms for short subcrown‐internode length, short coleoptile length, and short culm length of C.I. 13253 are related closely. The genetic associations between coleoptile and subcrown‐internode length with culm length were somewhat divergent. Results implied that one‐gene semidwarf types could be selected with long or short subcrown internodes. Unrestricted selection among semidwarf types for short subcrown‐internode or long coleoptile length may produce poor emerging types or shallow crown types, respectively.