Inheritance of Resistance in Two Triticum aestivum Lines to Russian Wheat Aphid (Hornoptera: Aphididae)

Studies were done to determine the inheritance of resistance in two wheat (Triticum aestivum L.) lines, PI 137739 and PI 262660, that were previously identified as resistant to Russian wheat aphid, Diuraphis noxia (Mordvilko), and to establish whether resistance was governed by the same or different genes. The resistant lines were crossed with the cultivars ‘Tugela’ and ‘Betta.’ Resistance reactions of backcross, F2 and F3 seedlings in greenhouse tests indicated that resistance in each line is controlled by a single dominant gene and that these genes are independently inherited. The gene symbols Dn1 and Dn2 are recommended for the resistance genes in PI 137739 and PI 262660, respectively.