Seedling response to stem rust for the second International Durum Yield Nursery 1970-71

Abstract

This report is intended to supply the International Durum Yield Nursery (IDYN) cooperators with seedling plant responses of the Second IDYN entries to stem rust. We hope that this information will be of value to cooperators in their breeding programs. Seedling reactions to 8 strains of P. graminis tritici are presented in Table 1 for the 24 Second IDYN entries. The strains selected for combinations of genes for pathogenicity, were studied under artificial conditions in the glasshouse, to identify resistance to this rust. The strains used are designated 151-l,2,3,6; 12-1,2,3,4,5,6; Race 13; 12-1,3,6; 113- 2,3,4,6; 15-2,4,7; 13-1,3,4,6 and 151-4, 6 where l=Sr6, 2=Srll, 3=Sr 9b, 4 =Sr Tt, 5 =Sr 1 7, 6 =Sr 8 and 7 =Yuma resistance. Numbers 151, 12, 13, 113 and 15 correspond to the standard international race system of classification. Seedling reactions were recorded using the standard international notation system. Previous studies with durums have shown that seedling reactions correlate closely with adult plant responses. Several entries apparently possess seedling resistance to all of the races tested. We therefore suggest that Wells, Leeds, Anhinga "S", Crane "S" (B), T. die. Vernum (TME-Tc2 / Z-BxW), ( B. Bal x BY2E-Tc) ( D. Buck x TME-Tc/LAK) and RAE - Tc 4 x STw 63 /AA "S" may serve as good sources of resistance. Several entries were observed to be segregating for resistance genes. Cooperators should take note of this if planning to make selections or crosses with these materials.