|Frey, Kenneth - IOWA STATE UNIVERSITY|
|Hammond, Earl - IOWA STATE UNIVERSITY|
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 2000
Publication Date: October 15, 2001
Interpretive Summary: Higher oil oats could be useful as a higher energy animal feed or even as an oil seed crop for human food oil. In a previous study, we reported that nine cycles of selection for higher oil content in oat resulted in dramatic increases in oil content. Lines with oil content of up to 18% were developed; these are by far the highest levels of oil content ever reported in oat. For high oil oat cultivars to be accepted by growers, however, their agronomic characteristics must meet minimum standards. In addition, it is important to know what the quality, as well as the quantity, of oil is in these higher oil oat lines. We evaluated oat lines from each of the nine cycles of selection and from the original unselected population for fatty acid contents and agronomic performance in field trials. Important grain quality traits such as test weight and seed weight and agronomic traits such as biomass and straw yield decreased following selection. The increased with each cycle of selection. Selection for increased groat-oil content increased the ratio of unsaturated to saturated fatty acids but reduced the mean grain quality and agronomic performance of the population. Thus, the selection program resulted in improving both the quantity and the quality of oat oil, but high oil oat cultivars can not be developed directly from these experimental lines. By measuring the genetic correlations between agronomic traits and oil content, however, we found that it should be possible to select for oats that have a favorable combination of high oil and good agronomic performance. Direct simultaneous selection for all important traits will be required to achieve this goal.
Technical Abstract: Increases in the groat oil content of oat (Avena sativa L.) increase the energy value of the grain and improve the feasibility of extracting oat oil for use as a vegetable oil. Nine cycles of recurrent selection for greater groat-oil content conducted in a genetically broad-based oat population resulted in dramatic increases in groat-oil content. Our objectives were to determine if selection for greater groat-oil content affected fatty acid composition, grain quality traits (test weight and seed weight), or agronomic traits (straw yield, biomass, harvest index, heading date, and height). We evaluated 100 random lines from the base (C0) population and each of the nine selection cycle populations in three environments in order to estimate means, genetic variances, heritabilities, and genotypic correlations of grain quality and agronomic traits. We also evaluated 20 random lines from each population to estimate changes in fatty acid contents. Oleate and stearate contents increased over cycles of selection, as did the ratio of unsaturated to saturated fatty acids. Palmitate, linoleate, and linolenate contents and all grain quality and agronomic traits except harvest index decreased over cycles of selection. There was no evidence for reduced genetic variance or heritability in C9 for any trait, but the genotypic correlations between agronomic traits and oil content fluctuated over cycles. Selection for increased groat-oil content improved oil quality but reduced grain quality and agronomic performance of the population.