Predicting Root Development in the Oilseed Lesquerella Under Two Irrigation Levels.

Lesquerella (Physaria fendleri) is a new oilseed crop identified to have good potential when planted as a winter annual in the U.S. Southwest. Its seed oil was tested to be a viable alternative to castor oil and possesses  similar properties ideal for industrial applications. We wanted to test if root observations at the seedling stage can be indicative of what the mature plants will later exhibit in the field as a means for selection. Two accessions of lesquerella, WCL-LO4-Gail and PI 596434, found to have highly contrasting root sizes at the seedling stage in the laboratory were planted at the Maricopa Agricultural Center and observed for root development and phenotypic response under two levels of irrigation (1,031mm and 1,429mm). Five sampling activities were made during the growing season (25DAE, 84DAE, 114DAE, 137DAE, 180DAE) at the crop’s vegetative, flowering, and pod maturity stages.  Results showed that the irrigation treatments have significant effects on lesquerella root diameter, total length, and amount of fine roots. PI 596434 consistently exhibited greater total root length and root volume than WCL-LO4-Gail suggesting that observations on these traits during the seedling stage can be successfully extrapolated to mature plants.