Breeding Approach to Diminish Barley Yellow Dwarf Epidemics in Kansas Wheat.

Barley yellow dwarf virus (BYDV) is a prevenient viral disease affecting winter wheat yields in Kansas and throughout the central great plains. Yield losses on commercial fields can exceed 35 percent if early infection occurs. The virus is spread through several aphid species such as the cherry-oat aphid, green bug and English grain aphids. Current attempts to control the virus are typically through management strategies and limited genetic resistance. Late planting and using chemical control such as seed treatment and insecticides are effective at suppressing the disease but do not eliminate the potential for the virus. Currently no commercial wheat varieties display resistance to barley yellow dwarf. However, some varieties are more tolerant than others. The objective of this project is to evaluate, identify and characterize new sources of resistance/tolerance to BYD by screening current varieties and Kansas State experimental advanced breeding lines. Experiments were conducted at the Kansas State University research farms at Rocky Ford (2016 and 2017) and Ashland Bottoms (2015). Replicated yield-plot nurseries containing six blocks of the annual yield nursery (AYN) material, one susceptible check (Art) and one tolerant check (Everest) were planted two to three weeks earlier than the recommended wheat planting dates. The six blocks were treated in to two groups. The treated group consisted of three blocks that were treated with seed treatment prior to planting and treated with foliar insecticide every 14-21 days post emergence depending on air temperatures. Growing season phenotyping data was done weekly using proximal sensing with unmanned aerial vehicle system (UAS). Yield data by block was obtained through the use of a small plot combine. Preliminary results show that on average, the susceptible check “Art”, had a 62% BYD infection rate and a 39% grain yield loss. Whereas, the “tolerant” check Everest, exhibited a 42% BYD infection rate and a 23% grain loss over two years. Furthermore, 10 experimental lines have demonstrated Everest like tolerance.