Survey of Root Variation in Lesquerella (Physaria fendleri) and Analysis of Response to Temperature Treatments.

Manipulating plant root systems is believed very important to optimize plant growth and productivity. In addition to above ground morphological characters, roots directly influence the capacity of plants in utilizing available water and soil nutrients. Elucidating root system architecture and its corresponding trait inheritance have been the focus of numerous research studies in commodity crops. In this study, we investigated the root system architecture of the new oilseed crop Physaria fendleri (syn. Lesquerella fendleri) to gather information on the available variability in the taxon. A limited set of eighteen P. fendleri accessions were grown in seed germination pouches for 21 days under two temperature regimens (21/13^oC and at 30/21^oC) that were previously found optimal for maximum plant productivity in the field. The seedlings were screened for nine parameters pertaining to the main and lateral roots, as well as the designated growth regions. The results showed that a substantial variation exists in total root size in the taxon and that the trait has significant positive correlation to five other root parameters. No significant difference was observed among the root parameters between the temperature treatments, except for root apical length and total root size which were both found to have larger values when the plants were grown at 30/21^oC. This is the first report of root variation screening in Physaria and it provides information for future experiments aiming to understand the physiology and genetics of these traits in the crop.