A high-oil castor cultivar developed through recurrent selection

Authors: Chen, Grace; Johnson, Kumiko; MORALES, EVA - US Department Of Agriculture (USDA); IBANEZ, ANA - University Of California, Davis; Lin, Jiann

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2017
Publication Date: 10/7/2017
Citation: Chen, G.Q., Johnson, K., Morales, E., Ibanez, A.M., Lin, J.T. 2017. A high-oil castor cultivar developed through recurrent selection. Industrial Crops and Products. 111:8-10. https://doi.org/10.1016/j.indcrop.2017.09.064.
DOI: https://doi.org/10.1016/j.indcrop.2017.09.064

Interpretive Summary: Castor (Ricinus communis) seed oil is the only commercial source of hydroxy fatty acid (HFA) which is used in industrial products such as lubricants, coatings, plastics and cosmetics. We previously screened and selected high-oil seeds from a base population of castor cultivar Impala. Through two cycles of recurrent selection of seeds, the average oil content of the Impala cv. increased from 50.33% dry weight (Cycle 0) to 54.47% dry weight (Cycle 2). This study evaluates the oil content and weight of field-grown seeds produced from the new population of Impala.

Technical Abstract: The purpose of this paper is to present and interpret the data obtained from field-grown castor seeds. Under greenhouse conditions, a previous recurrent selection for high-oil castor seeds from a base population resulted in a new population with an increased mean oil content from 50.33 to 54.47% dry weight, average single seed weight from 0.44 to 0.54 g, and correlation between oil content and weight from moderate (r = 0.43, p < 0.0001) to strong (r = 0.77, p < 0.0001). Here, we describe field trials to evaluate the oil content and seed weight of the new (Test), and base (Control) populations. Duplicated Tests and Controls were planted and the trials were repeated for two consecutive years. From planting to seed harvesting, no difference in growth pattern was observed in either of the populations. Test seeds had a mean oil contents of 54.01% dry weight, an average single seed weight of 0.54 g, and strong correlations between oil content and weight (r = 0.71 to 0.72, p < 0.0001), similar to the new population obtained from the greenhouse study. Correspondingly, Control seeds had a mean oil content of 50.5% dry weight, an average single seed weight of 0.44 g, and moderate correlation between oil content and weight (r = 0.43 to 0.44, p < 0.0001), comparable to previous data on the base population. The frequency distribution of oil content and seed weight in field- and greenhouse-grown castor seeds were similar. Our results confirm that recurrent selection for high-oil content seeds is an effective approach to increase the mean oil content of a castor population.