Evaluation of Spinach Cultivars for Downy Mildew Resistance in Yuma, AZ, 2024

Annual sentinel field trials expose spinach cultivars to naturally occurring endemic inoculum, providing insight into the performance of new and existing commercial varieties under field conditions. The evaluated hybrid cultivars incorporate a broad combination of resistance genes from both the male and female parent. A field evaluation for resistance to the downy mildew pathogen of spinach ( Peronospora effusa) was conducted in Yuma, AZ, in 2024. Disease development was due to naturally occurring inoculum. The disease incidence was recorded 41 days after the wet date for 70 cultivars. The disease incidence varied considerably among the cultivars tested, and the range was 0.0 to 96.7% infected leaves.