P-220 - Assessing yellow dwarf disease susceptibility in Nebraska’s wheat and barley varieties

Abstract Text: Barley yellow dwarf virus (BYDV) and cereal yellow dwarf virus (CYDV) cause yellow dwarf disease in cereal crops and exist as five major strains (BYDV-RMV, -PAV, -SGV, and -MAV, and CYDV-RPV) in the US cereal growing regions. Although BYDV-SGV was recently identified as a dominant strain in Nebraska, little is known about the response of popular wheat and barley varieties to BYDV strains. To address this, a multilocation varietal trial was performed with five winter wheat (Ruth, Freeman, Mace, Uncharted, SY Monument) and five winter barley (NB15420, NB21427, NB17401, NB19420, Fortress) varieties in a randomized complete block design. Disease incidence, aphid species composition, and aphid densities were assessed. Each treatment plot (7.525 m²) was replicated five times at three locations. Leaf samples were collected at the panicle initiation stage and analysed using multiplex single-step RT-PCR. Aphid populations were assessed using Berlese funnel traps. Our results showed significant differences in B/CYDV strain composition among wheat and barley varieties. ‘SY Monument’ was the most susceptible wheat variety, with BYDV-PAV as the most dominant strain (_˜34%). Similarly, ‘Fortress’ barley exhibited highest infection, with BYDV-MAV as the most dominant strain (_˜35%). Bird cherry oat aphid was found to be the most abundant aphid species. Furthermore, higher disease incidence was correlated with increased aphid abundance in respective wheat and barley varieties.