Chromosomal Location of Genes for Gibberellic Acid Insensitivity in 'Chinese Spring' Wheat by Tetrasomic Analysis

The tetrasomics of the homoeologous groups 2, 5 and 7 of‘Chinese Spring’wheat were, together with the euploid standard, screened at the seedling stage for sensitivity to exogenously applied gibberellic acid (GA³). Whilst the seedling length of lines tetrasomic for group 2 chromosomes were taller and those for chromosomes 5A, 5D and 7D shorter in both treatments (with and without GA³) compared to the euploid control, the remaining tetrasomics — 5B, 7A and 7B — were significantly shorter than the euploids in the GA variant only. These results suggest the presence of additional genetic factors for GA insensitivity on chromosomes of the groups 5 and 7 of hexaploid wheat. This corresponds with the localization of GA insensitive dwarfing genes on the homoeologous chromosomes 5R and 7R in diploid rye.