Development and utilization of phenotyping pipelines to assess resilience to transient abiotic stress in vegetable crop populations

Climate change and associated weather fluctuations are producing both long- and short-term variability in crop growing conditions, leading to a range of chronic and transient abiotic stresses. Reproducible methods to reliably assess crop germplasm resources for resilience to these abiotic stress types are required to identify elite accessions bearing traits that can be used in breeding programmes. Abiotic stresses rarely occur in isolation, and responses to combined stresses can often not be predicted from those to individual stresses, requiring assays employing multiple simultaneous abiotic stress types. In order to identify potential breeding material of interest we have utilized populations of vegetables from the Defra funded UK VeGIN project, which include diversity fixed foundation sets (DFFSs), recombinant inbred line (RIL) mapping and half-sib populations, in order to identify resilience to transient abiotic stresses in a range of vegetable crops. Using these populations, we have developed a number of phenotyping pipelines to assess resilience to single and combined transient seedling or transplant-stage abiotic stresses, in vegetable crops, namely drought, heat, waterlogging and salinity, in vegetable brassicas (Brassica oleracea L.), lettuce (Lactuca spp.), carrot (Daucus spp.) and onion (Allium spp.) germplasm. Significant (P≤0.05) variation in stress resilience was found across the studied populations. Overall, within crop species, responses to different individual stresses were not well correlated, however some lines exhibited resilience to multiple individual or simultaneous combined stresses. In B. oleracea, for example, abiotic stress resilience was identified across multiple crop types (e.g., cauliflower, broccoli) with some lines belonging to different crop types exhibiting resilience to multiple stresses. This work demonstrates the importance and utilization of different crop germplasm resource types that are promising for the development of more environmentally resilient vegetable crops.