Water Use and Water Use Efficiency of Three Brassicaceae Oilseeds under High‐ and Low‐yielding Environments

Brassicaceae oilseed crops have proven potential as vegetable oil feedstock for biofuels and food uses. However, meeting a growing demand for vegetable oils for food and industrial uses will require identifying oilseed species that are best suited for various growing environments within a particular region. The objective of this study was to compare growth dynamics, seasonal water use (WU), seed yields, and water use efficiency (WUE) of canola (Brassica napus L.), camelina (Camelina sativa L.), and white mustard (Sinapis alba L.) to determine their suitability under three different environments within the northern Great Plains. Comparisons were made among these species over three growing seasons between 2013 and 2016 at Morris, MN; Mandan, ND; and Sidney, MT, situated along a strong precipitation gradient from east to west. Generally, growing season precipitation was similar at Morris and Mandan, but both were considerably greater than at Sidney. Seasonal WU was similar among these oilseed species at Morris and Mandan but was greatest for camelina at the drier Sidney environment. Canola seed yield was the greatest at Morris and had higher WUE than camelina and white mustard. At Mandan and Sidney, canola and camelina had similar seed yields and WUE, which were generally greater than white mustard. Under abundant moisture and low stress (e.g., Morris), seed yield per millimeter of water used could be maximized by growing canola, while in a drier more stressful environment like Sidney, seed yield per millimeter of water used could be maximized by growing camelina.