Rapid development of a castor cultivar with increased oil content

Authors: Chen, Grace; Johnson, Kumiko; MORALES, EVA - Non ARS Employee; Mackey, Bruce; Lin, Jiann

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2016
Publication Date: 9/20/2016
Citation: Chen, G.Q., Johnson, K., Morales, E., Mackey, B.E., Lin, J.T. 2016. Rapid development of a castor cultivar with increased oil content. Industrial Crops and Products. 94:586-588. doi:10.1016.j.indcrop.2016.09.020.[Corrigendum: Industrial Crops and Products: 2017, p.101:103.]

Interpretive Summary: Castor (Ricinus communis) is an important oilseed crop of the Euphorbiaceae family. Castor oil contains an uncommon hydroxylated fatty acid, ricinoleic acid (or 12-hydroxyoleic) at 90% high concentration. The hydroxy group imparts unique chemical and physical properties that make castor oil a vital raw material for manufacturing numerous industrial products, such as high lubricity lubricants and greases, a variety of polymers traditionally made by petroleum-based products for various coatings, elastomers and plastics, and an array of castor oil derivatives utilized in cosmetic industry. Improvement of castor cultivars by increasing the oil content would be of great benefit as it contributes to oil yield and makes the production more cost competitive. We describe for the first time oil content improvement in castor through recurrent selection based on screening individual seeds using nuclear magnetic resonance spectroscopy (NMR).

Technical Abstract: Castor seed oil contains 90% ricinoleic acid which has a wide range of industrial applications. Improvement in oil content would be of great benefit to castor growers and oil processers. Two cycles of phenotypic recurrent selection were conducted through screening for high oil content castor seeds using magnetic resonance spectroscopy (NMR). Selection increased mean oil content of a base population (Cycle 0) of cultivar Impala from 50.33% to 53.87% in Cycle 1 and 54.47% in Cycle 2. Gains from Cycle 1 and Cycle 2 are 3.54% and 0.6%, respectively. The drop of gain in the second cycle indicates a genetic ceiling of oil content or/and low initial genetic variability of the base population. Nevertheless, the 54.47% mean oil content of Cycle 2 would rank the new Impala cultivar at the top 1% of the entire 1103 castor accessions maintained at the United States of Department of Agriculture (Wang et al., 2010). To our knowledge, this is the first report of utilizing NMR and recurrent selection for improving oil content in castor.