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Number 91: 15-19 (2000)
Research article
Morphological characterisation and evaluation of
the subdivision of Aegilops tauschii Coss.
P. Knaggs, M. J. Ambrose, S. M. Reader and T. E. Miller
John Innes Centre, Norwich Research Park, Colney, Norwich NR4
7UH, UK
Summary
In a study of plant morphology involving 54 accessions of
Aegilops tauschii Coss. held at the John Innes Centre,
Norwich, UK the subspecies strangulata and the ssp.
tauschii varieties typica, meyeri and
anathera were identified. Linear discriminant analysis, based
on sixteen morphological characters, found that ssp. strangulata
was morphologically distinct, being taller with a greater seed
weight, prominent stem curvature and a rounded seed shape. The
variety anathera was clearly separated on awn type and was, on
average, shorter than the other accessions but var. typica and
var. meyeri proved difficult to identify and were not easily
distinguished by multivariate analysis. Consequently, the subdivision
of Ae. tauschii on the basis of plant morphology appears to be
reasonably valid. Seven of the accessions showed promising resistance
to stripe rust infection, one was found to have a tough rachis and
there was significant variation overall for yield related characters
such as spikelet number, seed weight, leaf length and plant
height.
Key words: Aegilops tauschii, intraspecific
classification, genetic resources.
Introduction
Aegilops tauschii Coss. (syn. Ae. squarrosa L.) is
a species of goat grass with a centre of distribution in the south
Caspian area, spreading westwards to Turkey and eastwards to
Afghanistan and China. Considerable morphological variation exists
within the species and this allowed Eig (1929) to describe different
subspecies and varieties of Ae. squarrosa. He divided the
species into two subspecies, eusquarrosa and
strangulata, and described three varieties within
eusquarrosa -- typica, meyeri and anathera.
Hammer (1980), using the correct name Ae. tauschii, renamed
ssp. eusquarrosa as ssp. tauschii. He also divided ssp.
tauschii into varieties, with Eig's var. typica
becoming var. tauschii and retaining var. meyeri
and var. anathera. He also added var. paleidenticulata.
However, these divisions were not formally recognized by van Slageren
(1994) in his monograph of Aegilops. This was partly because
of the existence of intermediate and hybrid forms (Kihara et al.
1965) but was also influenced by various molecular studies in which
morphological variation failed to match or predict the genetic
variation (Kim et al. 1992; Tsunewaki et al. 1991; Lubbers et al.
1991).
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