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Avena agadiriana is
the newly described tetraploid species, which is very similar to
A. canariensis. This species were distributed from Casabranca
to Tiznit along the Atlantic coast of Morocco. Moreover, its
distribution area is divided into two parts by Haut-Atlas mountains
(alt. 4165 m). The northern part of the mountains is very heavy clay
soil whilst the southern part is very dry and sandy soil. The genetic
variability of 6 populations was as follows; an average of 46.3%
variable loci, 1.50 alleles per locus and an expected heterozygosity
of 0.154 were recorded by utilizing the isozyme frequency.
Dendrogram. resulting from a UPGMA cluster analysis showed a major
dichotomy between the southern and northern part population.
Chromosome variations, satellite-deficiency and translocation, were
observed by hybridization between those two groups. The northern part
group (3 population) is always having two pairs of satellite
chromosomes and is later maturing type whilst the southern one (3
populatios) is always having three pairs of satellite chromosomes and
is earlier maturing type. Intraspecific: variations of isozyme and
chromosome in A. agadiriana were very similar to A.
canariensis. The chromosome types of A. canariensis were
mainly in accord with the elevation of havitats but those of A.
agadiriana were associated with specific soil characteristics and
edafic factors.
Avena maroccana is a typical weedy species forming
massive stands mixed with A. sterilis in cereal fields on
heavy alluvial soil to which its large spikelet is well adapted. It
has been discovered and repeatedly found only in the triangle between
Tiflet-Rommani-Tedders in Morocco. It has been stated that A.
maroccana, which is closely related to the hexaploids on the
basis of morphology and meiotic affinities, appears to have a
combination of the complements of A. canariensis and one of
the C genome diploids. This species is distributed in the small area
so that there is no sign of ecotypic differentiation whithin the
species. However, the genetic variability of 11 populations was
relatively larger than the former two species. An average of 44.3%
variable loci, 1.82 alleles per locus and an expected heterozygosity
of 0.182 were recorded. Dendrogram resulting from a UPGMA cluster
analysis showed two clusters, which are roughly correlated with the
geographic distance, and two independent populations (M7 and M9).
Each population of A. maroccana appears to be adapted to a
distinct microhabitat. Chromosome analysis on this species is now in
progress.
Avena longiglumis is sporadically distributed in the Iberian
peninsula, North Africa and Israel. It has very long slightly
subequal glumes and very large anthers; the florets is the dispersal
unit. It consists of two ecotypes, one a coastal type of robust, tall
plant with large drop panicles; the other a desert type of shorter,
slender plants with small panicles. Both ecotypes are specialized for
sandy soils. The genetic variability of 6 populations was recorded as
follows; an average of 38.3% variable loci,1.78 alleles per locus and
an expected heterozygosity of 0.160. Out of the 6 populations, one
was the desert type (M61) and five were the coastal types. However,
isozyme differentiation between two ecotypes was not detected.
Chromosome analysis on A. longiglumis is also under
investigation.
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