INHERITANCE OF SAWFLY REACTION AND STEM SOLIDNESS IN SPRING WHEAT CROSSES: SAWFLY REACTION

Inheritance of reaction to the wheat stem sawfly, Cephus cinctus Nort., was studied in populations of F 3 and B 2 lines from the cross Red Bobs × C.T. 715 (Triticum aestivum L.), and the respective backcrosses. The data supported the hypothesis that the varieties differed by three genes for sawfly reaction. A major influence was attributable to one gene. Its allele for susceptibility when homozygous was epistatic to the other two genes. Its allele for resistance was twice as effective as either of the other genes in conditioning resistance. The other two genes lacked dominance and were equal in their influence on sawfly reaction.Correlation coefficients showed that sawfly reaction was not associated with reaction to race T-2 of Tilletia caries (DC.) Tul., heading date, or awnedness. Sawfly susceptibility was weakly correlated with height.