Gibberellic acid insensitive semi-dwarfing genes, RhtB1b and RhtD1b, have been used extensively in the development of semi-dwarf wheat varieties in the Great Plains winter wheat region. These genes improve harvest index under higher yielding environments but results have been mixed under less than optimal conditions partially due to their reduced coleoptile length. Interest in gibberellic acid sensitive Rht8, an alternate semi-dwarfing gene, has increased due to the discovery of, Xgwm261, a closely linked (0.6 cM) microsatellite marker. Our objectives were to i) determine the allelic variation at the Xgwm261 marker locus for a set of historical and current Great Plains cultivars, ii) identify alleles at the Rht-B1, Rht-D1 locus and iii) evaluate the pleiotropic effect of these semi-dwarfing genes on height, gibberellic acid sensitivity, and coleoptile length. Four allelic classes were identified among the Great Plains cultivars with fragment sizes of 165 bp, 174 bp, 192 bp, and 210 bp. Rht-B1b, Rht-D1b and tall genotypes were identified although the percentages of the three genotypes differed within each Xgwm261 allelic class. Variation among Xgwm261 allelic classes for height, gibberellic acid sensitivity and coleoptile length was identified at P<0.05. RhtB1b and RhtD1b were associated with decreased height and suppression of gibberellic acid response within the four allelic classes of Xgwm261. However, no relationship was found between RhtB1b or RhtD1b and coleoptile length. We were unable to verify the diagnostic capabilities of microsatellite marker, Xgwm261 to identify Great Plains varieties with reduced height, gibberellic acid sensitivity and long coleoptiles.