Jointed goatgrass (Aegilops cylindrica Host) infestations in winter wheat
(Triticum aestivum L.) production regions of the central and western USA result in severe
economic losses in the wheat market. Field and greenhouse studies were conducted to
determine the vernalization requirements of winter wheat, spring wheat, jointed
goatgrass, and wheat by jointed goatgrass reciprocal hybrid plants. In field studies,
jointed goatgrass plants required more vernalization to produce spikelets and germinable
seed than 'Madsen' winter wheat plants. In greenhouse studies, plants of jointed
goatgrass populations collected from Oregon and Washington wheat fields required fewer
vernalization days to reach the joint stage than Madsen plants. Detailed observations in
the greenhouse revealed a longer period between jointing and anthesis for most jointed
goatgrass populations that was overlooked in field studies. Vernalization for 6-wk
represents the minimum treatment for synchronous reproductive development among
jointed goatgrass populations, Madsen winter wheat, and Madsen by jointed goatgrass
hybrids, yet the risk of gene transfer might be greater after 7-wk vernalization. In the
jointed goatgrass populations tested, there was not selection for a vernalization
insensitive growth habit. Because jointed goatgrass spikelets often contain two seed,
germination was recorded for primary and secondary positioned seed. Germination of
freshly harvested jointed goatgrass seed was promoted by 25/15 C day/night
temperatures. However, light and 30/20 C incubation was necessary for maximum
germination of non-dormant, primary positioned seed. Both primary and secondary
positioned seed within jointed goatgrass spikelets were non-dormant after 16-wk after-ripening
at 22 ± 2 C. Under optimum growing conditions, no planting depth selectively
allowed wheat germination and emergence while preventing jointed goatgrass
germination and emergence. Glume removal did not alleviate dormancy completely in
jointed goatgrass seed. Research confirmed jointed goatgrass population polymorphism
for vernalization requirements and seed dormancy. Jointed goatgrass reproductive
variability might be part of a general purpose genotype strategy to germinate and
colonize a wide range of environments. Wheat by jointed goatgrass hybrid plants should
be removed from winter and spring wheat fields. Despite a short dormancy period, three
or more years of rotation outside of winter annual crops may be necessary to reduce
populations of jointed goatgrass. / Graduation date: 2006
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28806 |
| Date | 12 October 2005 |
| Creators | Fandrich, Lynn |
| Contributors | Mallory-Smith, Carol A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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