|Cruz, von Mark|
Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2013
Publication Date: 3/1/2013
Citation: Cruz, V.V., Walters, C.T., Dierig, D.A. 2013. Dormancy and after-ripening response of seeds from natural populations and conserved Physaria (syn. Lesquerella) germplasm and their association with environmental and plant parameters. Industrial Crops and Products. 45:191-199.
Interpretive Summary: The response of seeds from wild populations in cold storage (ex situ) is important to know for long-term preservation of the germplasm. The germination response of seeds to different seed storage durations and temperatures was tested on wild populations of the new crop species lesquerella. Lesquerella is a new oilseed crop being developed in the United States as domestic source of novel industrial oils. Numerous accessions of lesquerella are conserved in the U.S. National Plant Germplasm System (NPGS). Significant differences in germination of lesquerella seeds among the different storage durations and temperatures were observed. Likewise, associations of the germination responses to climatic data and soil parameters recorded from the natural populations were determined. This information about seed afterripening and dormancy will be valuable to plant curators to help them devise optimum strategies for germplasm management and to new crop breeders who routinely maintain breeding materials during the crop’s cultivar development process.
Technical Abstract: Seed dormancy studies in Physaria are still limited to date. To further understand this trait as well as the after-ripening response in this new crop taxa, we sampled from different seed lots of genebank conserved accessions and from natural populations of P. fendleri (syn. Lesquerella fendleri) and P. gordonii (syn. L. gordonii) in the U.S. Southwest. We subjected the seeds from the natural populations to different after-ripening regimens, storing them over two saturated salt solutions (LiCl and MgCl2) to equilibrate seed moisture levels, at three storage temperatures (5, 25, and 35oC) for various lengths of time (4, 8, 12 weeks) and then germinated the seeds at different temperatures (constant 24oC and alternating 15/25oC). Seeds from the conserved accessions were subjected to 4 and 12 weeks storage at MgCl2 and at 15/25oC only, due to limited amount of seeds. Results obtained from the seeds of natural populations indicate significant differences in total germination among storage durations, and between temperatures of germination. In contrast, no significant difference in the total germination was found in seeds of the conserved accessions between the storage durations, even with gibberellic acid supplementation. We further explored possible associations of the observed germination responses to climatic data and other environmental and soil parameters of the sites where the natural populations were found.