Variation in Water Stress of 12 Brassica Genotypes Across Different Environments Based on Delta 13c Signature.

Hydrotreated renewable jet fuel (HRJ) has been commercially demonstrated, but large-scale production has been hindered by feedstock costs. Certain Brassica oilseed crops can serve as feedstock, but the best agronomic and economic choice may differ by environment. A multi-location study evaluated productivity and response to environment of 12 genotypes representing six species (Brassica napus, B. rapa, B. juncea, B. carinata, Sinapis alba, and Camelina sativa) grown under rain-fed conditions. The study was conducted at eight locations spanning the western Corn Belt, across the North and Central Plains to the Pacific Northwest USA. Delta ¹³C signature of seed was used as an indicator of water stress and was compared across genotypes and locations. Averaged across all genotypes, delta ¹³C values by location tended to correspond with growing season precipitation, with the highest values (lowest negative signature) represented by the driest environments. Averaged across the four driest sites, delta ¹³C of camelina was consistently the lowest indicating the least amount of stress, followed by S. alba, while certain cultivars of B. carinata and B. napus had the highest values signifying more water stress. Comparison of seed yields for the 12 genotypes differed among locations. Other factors such as stand establishment, pests, diseases, and weed pressure must be considered, and will be further evaluated to identify best HRJ feedstock choices for a given cropping region or area.