Exploiting the USDA Castor Bean and Peanut Germplasm Collection as a Potential Energy Crop for Biodiesel Production.

Biodiesel (fatty esters) produced from seed oils or animal fats by transesterification, is one of the most promising alternative renewable fuels in the future. In contrast to petroleum diesel, the utilization of biodiesel has several main advantages which are environmentally friendly, agriculturally economical, continually renewable, and long-term fuel-supply dependable. Currently, over 90% of the consumed biodiesel in the U.S. is from soybean oil. To diversify the feedstock for biodiesel production, two oilseed crops (castor bean and peanut) were selected and exploited from the USDA germplasm collection. Our strategy includes four major continuous steps: (1) quickly identifying accessions with high oil content by highly efficient screening methods, (2) selecting the highest yielding accessions from identified accessions by field plot tests, (3) mining genetic diversity of accessions with high oil yield (gallons/ha) by high throughput genotyping, and (4) determining the fatty acid composition of oil by gas chromatography. Forty-eight accessions from each species have been screened, and the oil content ranged from 42.6% to 53.8% in peanut seeds, 21.3% to 37.2% in castor bean seeds, respectively. The real castor bean seed oil content should be higher than we obtained due to the limitation of our pressing method. The yield test for accessions with high oil content is in progress. More accessions will be screened for high oil content. The accessions producing high oil yield with appropriate fatty acid composition and diverged genetic diversity will be recommended as parents for developing high oil yield cultivars.