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Résumé :
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The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a serious pest in wheat (Triticum aestivum L,), Four Russian triticale (X Triticosecale Wittmack) lines, PI 386148, PI 386149, PI 386150, and PI 386156, have been the most resistant triticales to the RWA in several screening tests. Resistance is controlled by a single dominant gene at a common locus in the three triticale lines PI 386148, PI 386149, and PI 386156. However, expression of these resistance genes in a wheat background and the inheritance of resistance in PI 386150 have not been determined. The objectives of this study were (i) to assess the transmission and the expression of RWA resistance in triticale x wheat hybrids, (ii) to determine the inheritance of resistance in PI 386150, and (iii) to identify the rye chromosome(s) from Secale montanum Guss. associated with RWA resistance. Advanced generations from crosses between PI 386148 triticale x 'Lamar' wheat and PI 386150 triticale x Lamar were produced and the progenies screened to determine their reaction to the RWA. All F-1 plants derived from both crosses were resistant indicating that resistance is dominant in both triticale lines. C-banding and in situ hybridization with the p Sc119.1 probe, a rye-specific DNA probe, showed that chromosome 4 R(mon) was associated with resistance in PI 386150. The results of this study should facilitate the transfer of the resistance gene(s) from these triticale lines into wheat.
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