awn

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awn

any of the bristles growing from the spikelets of certain grasses, including cereals
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

awn

[ȯn]
(botany)
Any of the bristles at the ends of glumes or bracts on the spikelets of oats, barley, and some wheat and grasses. Also known as beard.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The awnless pollinator and awned female parents, including the semidwarf wheat, were isolated 30 cm from each other.
The parental lines used were an awnless hulled cultivar, Marion referred to as `Marion QC' by Dubuc and Comeau (1989); two awnless nonfatuoid naked oat cultivars, `Terra' (McKenzie et al., 1981) and `Tibor' (Burrows, 1986); and two fatuoid naked oat lines, NO753-2 and NO753-2A.
Panicles without any geniculate lemma awns were classified as awnless. Panicles with geniculate lemma awns typically exhibited some within-panicle variation for the number of awns per spikelet, but were classified as having up to one, two, three, or four awns per spikelet according to the highest number of geniculate awns observed on any spikelet within the panicle.
In each of the five crosses, up to 12 individual [F.sub.2] plants, including five or six with high proportions of naked grain (i.e., the cleanest threshing [F.sub.2] plants) and five or six with low proportions of naked grain (i.e., the poorest threshing [F.sub.2] plants), were chosen from each of four categories of plants on the basis of awn number per spikelet (i.e., awnless, one awn per spikelet, two awns per spikelet, three awns per spikelet) to be advanced to the [F.sub.3] generation.
In each of the [F.sub.2] populations of each of the five crosses, observed phenotypic ratios for awn number were compared to a 1:2:1 ratio (1 awnless plant:2 plants with one awn per spikelet:1 plant with two or more awns per spikelet) and to a 3:1 ratio (3 plants with no awns or one awn per spikelet: 1 plant with two or more awns per spikelet) by [chi square] tests for goodness-of-fit.
Within [F.sub.2:3] families derived from awnless [F.sub.2] plants and from [F.sub.2] plants with one awn per spikelet, observed phenotypic ratios for awn number were compared with1:2:1 and 3:1 ratios, by [chi square] tests for goodness-of-fit.
For the number of geniculate awns per spikelet (i.e., the fatuoid character), all of the [F.sub.2] populations from the crosses involving Marion deviated significantly from the 1:2:1 ratio (i.e., 1 awnless plant:2 plants with one awn per spikelet:1 plant with two or more awns per spikelet), with more than the expected number of awnless plants and less than the expected number of plants with one awn per spikelet (Table 1).
Single-locus models in which the expression of the dominant gene is variable (i.e., some plants with all naked grain and some mosaic plants, or some awnless plants and some plants with one awn per spikelet) seem more appropriate, but there were some cases of significant deviation from the 3:1 ratios expected for these models.
The lemma is midwide, short, glabrous, pointed and awnless, and may overlap slightly on the palea.
Whitmar is an awnless cultivar developed from a population collected near Colton, Whitman County, WA, and Goldar is an awned cultivar developed from a population collected near Anatone, Asotin County, WA.
Sixteen of the P-7's 25 component populations are predominately awned and 9 are predominately awnless (Larson et al., 2000).