Genetic Variation for Resistance to Russian Wheat Aphid in F2-Derived Families of Wheat (Triticum aestivum L.)

The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a significant insect pest of wheat worldwide. The objective of this study was to assess the genetic variation within and between F2-derived families for reaction to RWA using F3 and F4 families originating from individual F2 plants of a cross between the susceptible line (synthetic hexaploid-11) and the resistance cultivar (‘Halt’). The RWA damage of individual plants within each family was measured using different procedures. Their reaction types were combined into a single data for each individual family (derived from an individual F2 plants) and subjected to statistical analysis. Results indicated that the genetic variation between F2-derived families is greater than within F2-derived families for RWA resis-tance. Broad-sense heritability of RWA resistance, calculated by partitioning phenotypic variation into genetic and environmental components, was 73.2%. A narrow-sense herita-bility estimate of 30% was obtained for the RWA resistance in the ‘Halt’ synthetic hexaploid-11 cross using parent-offspring (F3: F4) regression procedure.