Degree Type


Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Kenneth J. Frey


An increase in the groat (caryopsis) oil content of oats (Avena sativa L.) could result in development of oilseed oat cultivars. Oat oil is a high quality vegetable oil suitable for human consumption. Additionally, oat oil may prove a valuable source of antioxidant compounds. In this study, three cycles of phenotypic recurrent selection for high groat-oil content were conducted in an introgressed oat gene pool constructed to contain high-oil alleles from both A. sativa and the wild hexaploid oat A. sterilis L. in an adapted agronomic background. Selection for groat-oil content was applied to individual F[subscript]1 plants, recombining the highest 10% to form the improved populations. One year was required to complete each cycle of selection. Response to selection for groat-oil content was evaluated for groat-oil content per se, oil yield per unit land area, and for several unselected agronomic traits;Gains in groat-oil content were realized both in cycle means and individual line performance. Groat-oil content increased linearly 9.26 g kg[superscript]-1 per cycle of selection, subsequently increasing oil yield 21 kg ha[superscript]-1 per cycle. Cycle three mean groat-oil content represented an increase of 135% over the mean of currently used commercial oat cultivars. Highest groat-oil content of any indiviual line was 144.8 g kg[superscript]-1. Broad-sense heritability and genetic variance remained high and significant, suggesting continuing progress;Phenotypic recurrent selection for high groat-oil content resulted in no significant correlated change in mean expression of any unselected agronomic trait measured. Declines in genetic variance, however, were noted for several traits and may have resulted either from selection for high groat-oil content or culling of populations for good agronomic type. Phenotypic and genetic correlation coefficients revealed negative, though mostly nonsignificant, relationships between groat-oil content and several traits which may reflect a purported bioenergetic limitation to increasing groat-oil content in oats;Results of this study suggest that phenotypic recurrent selection and the introgression of wild oat germplasm into the cultivated oat gene pool can be effective in the modification of chemical composition of the oat grain.



Digital Repository @ Iowa State University,

Copyright Owner

Christopher Vaughan Branson



Proquest ID


File Format


File Size

91 pages