Molecular Characterization of Resistance to Russian Wheat Aphid (Diuraphis noxia Kurdjumov) in New Resistant Genotype IG 100695

The Russian Wheat Aphid (RWA), Diuraphis noxia (Kurdjumov), is an important pest of small-grain cereals, particularly wheat in Turkey and worldwide. The most efficient struggle with the RWA is to identify of resistance sources and introduce resistance genes into susceptible wheat genotypes by means of different plant breeding methods and marker-assisted selection (MAS). In this study, one accession from ICARDA was identified highly resistant to the most virulent RWA population (Biotype 2) in Turkey in RWA screening. Aims of this study therefore were to determine the mode of inheritance of this resistance gene, to identify wheat microsatellite markers closely linked to the gene, and to map the chromosomal location of the gene. SSR (simple sequence repeat) markers were scored in a mapping population of 190 F₂ individuals, while phenotypic screening for resistance was performed in F_2:3 families derived from a cross of Basribey (susceptible) and IG 100695 (resistant). Phenotypic analysis showed that resistance to RWA was controlled by a single dominant gene in this accession. Also, the resistance gene was mapped on the short arm of chromosome 7D with four linked SSR markers which could be beneficial in RWA resistance breeding in wheat.