Identifying New Oilseed Crops
Indigenous species are being screened for seed oil content to identify alternative oilseed crops for sustainable agriculture.
‘Shea butter’, the oil extracted from the seed Vitellaria paradoxa, is used throughout Africa to protect and moisturise the skin.
Seed energy reserves in the form of oil, carbohydrates and proteins are essential for germination and early seedling development, and are attractive sources of nutrition and raw materials for people across the world. Oilseeds can provide both food and biofuel, and the by-products from processing may have value, for example as use for animal feed or production of cosmetics. Indigenous species are often grown on a small scale in a sustainable way which has benefit to the local community and avoids the destruction of wild vegetation and natural habitats associated with large-scale production. Many wild oilseed species are also highly adapted to the environment they grow in and possess high genetic diversity, offering a source of desirable traits for breeding programmes. Indigenous species therefore offer a solution to the increasing global demand for food and energy.
Preservation of indigenous germplasm in genebanks is essential, but oil content has implications on water relations and therefore longevity during storage and so accurate determination of oil content is vital. Furthermore, oil composition can dictate the optimal temperature of seed storage which may require the development of alternative storage techniques for some species.
To screen species which are considered to have potential as oilseed crops, a universal method for quantifying seed oil content using supercritical fluid extraction was developed (Seal et al. 2008). Screening is taking place on seeds of plants with socio-economic importance such as the Cactaceae and halophytes which we have found to be high in oil content (Seal et al., 2008; Seal et al., 2010) and adapted to survive in extreme environments. Other species selected for research are based on key genera in current usage such as Jatropha (Euphorbiaceae) and Allanblackia (Guttiferae) of which seed biology understanding is limited. Comprehensive screening within a family is an important focus as this may identify many species not currently used by humans; for example, J. curcas is a well-known oilseed species but the genus Jatropha consists of another 174 species that relatively little is known about. Access to the unique material in the MSB Partnership is enabling such comparative studies. To increase the rate of screening and enable the oil content of rare and small seed collections to be quantified, work is currently underway to develop a non-destructive analytical method.
This project is part of the research theme ‘Seed Futures’ and the outputs are the generation of oil content data (to date over 60 species) included in databases such as the ‘Seed Information Database’ and the ‘Cactus Seed Biology Database’, publication of data and methods in peer-review journals, presentation of data at several international conferences and training of national and international visitors in analytical techniques (to date, five visiting scientists have been trained). For those species which are identified as potential oilseed crops, the thermal properties of the seed are investigated to assess suitability for storage at genebank temperatures (see project: Seed Thermal Fingerprint and Oilseed Storage Risk). This combination of biochemical and biophysical approaches is essential to preserve the future availability of wild oilseed germplasm.
Project partners and collaborators
Instituto de Investigaciones Agropecuarias
Kunming Institute of Botany
Jardin Botanico Nacional ¨Dr Rafael Maria Moscoso¨, Santo Domingo
Universidad Nacional Autónoma de México
University of Sussex
Key papers published since 2006:
Chen, H., Pritchard, H.W., Seal, C.E., Nadarajan, J., Li, W., Yang, S. & Kranner, I. (2011). Post desiccation germination of mature seeds of tea (Camellia sinensis L.) can be enhanced by pro-oxidant treatment, but partial desiccation tolerance does not ensure survival at -20 °C. Plant Science, accepted (IF 2.481).
Xia, K., Seal, C.E., Chen, W.-Y., Zhou, Z.-K. & Pritchard, H.W. (2010). Fruit oil contents of the genus Quercus (Fagaceae): A comparative study on acorns of subgenus Quercus and the Asian subgenus Cyclobalanopsis. Seed Science & Technology 38, 136-145 (IF 0.631).
Seal, C.E., Zammit, R., Scott, P., Nyamongo, D.O., Daws, M.I. & Kranner, I. (2010). Glutathione half-cell reduction potential as a seed viability marker of the potential oilseed crop Vernonia galamensis. Industrial Crops and Products 32: 687–691 (IF 2.507).
Seal, C.E., Flores, J., Ceroni Stuva, A., Dávila Aranda, P., León-Lobos, P., Ortega-Baes, P., Galíndez, G., Aparicio-González, M.A., Castro Cepero, V., Daws, M.I., Eason, M., Flores Ortiz, C.M., del Fueyo, P.A., Olwell, P., Ordoñez, C., Peñalosa Castro, I., Quintanar Zúñiga, R., Ramírez Bullón, N., Rojas-Aréchiga, M., Rosas, M., Sandoval, A., Stuppy, W., Ulian, T., Vázquez Medrano, J., Walter, H., Way, M. & Pritchard, H.W. (2009). The Cactus Seed Biology Database (release 1). Royal Botanic Gardens, Kew.
Seal, C.E., Kranner, I. & Pritchard, H.W. (2008). Quantification of seed oil from species with varying oil content using supercritical fluid extraction. Phytochemical Analysis 19: 493-498 (IF 1.848; times cited = 4).
Conferences and workshops:
Pritchard, H.W. (2011). Seeds as natural capital. Invited lecture. International Society for Seed Science, 10th Conference, Brazil.
Seal, C.E., Zammit, R., Scott, P., Flowers, T. J. & Kranner, I. (2010). Seed storage and biochemical traits of the halophyte Suaeda maritima. COST Action FA0901 first scientific meeting, Naples, Italy.
Xia, K., Pritchard, H.W., Stuppy, W., Zhou, Z.K. & Daws, M.I. (2008). Comparative seed biology of Chinese evergreen oak seeds (Quercus subgen. Cyclobalanopsis, Fagaceae). 9th Conference on Seed Biology, Olsztyn, Poland.
Seal, C.E., Kranner, I., & Pritchard, H.W. (2007). Using green chemistry to extract the oil from seeds of the Cactaceae and other underutilised crops. 5th International Symposium on New Crops and Uses: their role in a rapidly changing world. University of Southampton, UK.
Links to other projects:
Cactus Seed Biology Database
Climate change, species vulnerability and germination thresholds
Seed Thermal Fingerprint and Seed Storage Risk
Taxonomy of Vitamin E Distribution Across the Plant Kingdom
Sustained Plant Conservation in the Insular Caribbean
Ex situ Conservation of Plant Germplasm from Arid and Semi-Arid Zones of Mexico