Rapid phenotypic assessment of bird cherry‐oat aphid resistance in winter wheat

Abstract

Abstract Rhopalosiphum padi L. causes significant damage to winter wheat (Triticum aestivum L.), even without obvious aboveground symptoms of injury. Our objectives were to develop a juvenile‐plant bioassay for bird cherry‐oat aphid (BCOA) resistance that allows rapid phenotypic differentiation. Central features of the bioassay include root and shoot weight measurements of 3‐week‐old seedlings produced in seed germination pouches, a 14‐day aphid exposure period, and a non‐infested control treatment to establish a baseline for expected biomass per genotype. Cultivars used in bioassay development were ‘Illinois Rustproof’ and ‘Skala’, which showed smaller BCOA‐induced reductions in biomass than the more susceptible genotypes, ‘Patrick’ and ‘Scout 66’. Mean reductions in root biomass were 48% for ‘Patrick’ and ‘Scout 66’, compared with 29% for ‘Illinois Rustproof’ and ‘Skala’. This rapid and repeatable bioassay is extendable to large wheat collections and inbred line populations.