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Discussion-conclusions
The discovery of an Ae. ventricosa population in
Makedonia, northern Greece, distant from the distribution area of the
polypIoid species and in the gap between its parent species
(analysers) distributions, gives room for assumptions regarding the
occurrence of this population and the evolution of the species.
According to Eig (1929), the genus has been developed in the Upper
Tertiary, when Balcan peninsula, Asia Minor, Crete and Cyprus were
united in one continent called "Aegeide", and South Europe and Africa
were united by land bridges. Aegilops ventricosa was probably
developed somewhere along the axis from North Greece to Middle East
and migrated through the existing land bridges to Africa. The parent
species gradually moved widely apart to areas bestly suited for their
growth because of changes in the climate of the region.
However, Kihara (1954) proposed an alternative theory, according to
which polyploid species were distributed rather recently from the
center of their origin to the Mediterranean coasts and islands
through migration of man.
On the basis of the above theories, the possible explanations for the
incidence of the discovered Ae. ventricosa population in North
Greece are:
1. Recent migration: The collection site is in the transport
axis from Italy to North Greece to Asia minor. Passive accidental
transport from South Italy is possible. Passive transport by
migrating birds from south Italy or northern Africa is a questionable
alternative.
2. Early migration: Mediterranean had seen big population
migrations and trade transactions at least some thousand years BC.
and Greece was among the most active places in this respect. North
Greece was the bridge between western Europe and Asia minor from
early times. The collection site lies on the transport axis from Rome
to Constantinoupolis (Istanbul) constructed by the Romans for trade
or military purposes, the famous "Egnatia Way". An early accidental
transfer of Ae. ventricosa by man in that area is an
alternative hypothesis.
3. Ancient remnant: A very slim possibility for the population
to be a relic from the Upper Tertiary distribution of the then
created polyploid has also to be considered.
In conclusion, further comparative morphological, cytological and
biochemical studies are needed to elucidate things. Seeds of the
species are available on request for such studies. However, it must
be emphasized that Greece has not been adequately explored in the
past. Recent short multicrop explorations by Gene Bank scientists
discovered many cereal species never before reported to exist in
Greece i. e., Hordeum agriocrithon, and Aegilops speltoides
var. aucheri.
Therefore species oriented systematic explorations might prove
both theoretically and practically rewarding and are scheduled for
the near future.
References
Chapman CGD (1985) The Genetic Resources of Wheat. A survey and
strategies for collecting. Rome IBPGR 42pp.
Eig A (1929) Monographisch-Kritische Ubersicht der Gattung Aegilops.
Report spec. nov. reg. veg. Beih 55:1-228.
Harlan JR and Zohary D (1976) Distribution of wild wheats and barley.
Science 153: 1074-1080.
Kihara H (1954) Consideration on the evolution and distribution of
Aegilops species based on the analyser method. Cytologia 19:
336-357.
Kimber G and Sears ER (1983) Assignment of genome symbols in the
Triticinae. Proc 6th Int Wheat Gen Symp, Kyoto Japan: 1195-96.
Tanaka M and Tsujimoto H (1991) Natural habitat of Aegilops
squarrosa in Xinjiong Uygur, China. Wheat Inf Serv 73: 33-35.
Zhukovsky PM (1928) A critical-systernatical survey of the species of
the genus Aegilops L. Bull App Bot Gen PI Breed 18:
417-609.
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