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3. Amphiploids with 2n =
56
Octoploid triticale
The first octoploid triticale in Bulgaria was obtained by D. Kolev
(1968). After that many octoploid forms have been realized and
employed in the triticale breeding programme due to their short
stems, spike productivity and increased winter hardness (Baeva 1981,
Tsvetkov 1989).
T. sphaerococcum x Secale cereale
Popov and Stankov (1979) described this amphiploid, obtained by using
two fines of T. sphaerococcum and a rye form C-2. Spike
fertility is low (10-12 seeds per spike) and aneuploid variation in
the progeny reaches 40%. The amphiploid shows high levels of powdery
mildew resistance and high protein content.
T. aestivum x Ae. speltoides
This newly obtained amphiploid utilizes wheat cultivars 'Chinese
Spring' and 'Trayana' (winter type form, IWS-General Toshevo
selection). The amphiploid having 'Trayana', includes
speltoides cytoplasm, because the reciprocal F1
hybrid did not survive after colchicine treatment. The fertility is
very low (1-10 seeds per spike) and is genetically unstable. Powdery
mildew attacks plants to varying degrees.
4. Amphiploids with 2n = 64
The amphiploid comprises species of Aegilops (Ae.
squarrosa var. strangulata, as mother line), Haynaldia
(H. villosa), Triticum (T. dicoccum var.
Khapli-III and T. palaeocolchicum), and Elymus (E.
giganteus). This shows resistance to fungi, high protein content,
good crossability to common wheat, but the fertility is very low
(0.5-1.0%).
Intraplant variability is observed for many morphological traits. The
amphiploid is preferentially maintained through vegetative
propagation.
5. Amphiploids with 2n = 70
T. aestivum x Ae. variabilis
This is genetically unstable, with fragile black spikes and low
fertility. Some of the plants in progeny are sterile (Spetsov 1988b).
Powdery mildew attacks plants to a lower degree compared to the
common wheat cultivars 'Charodeika' and 'Roussalka'. A pair of Ae.
variabilis chromosomes has been added to the genome of later
variety, inducing high resistance to powdery mildew fungus (Spetsov
and Iliev 1991).
T. aestivum x Ae. kotschyi
This is also unstable, but the fertility is better than the above
mentioned fine with Ae. variabilis. In the progeny plants vary
mainly due to the glume pubescence, irrespective of their high level
of powdery mildew resistance, high tillering and winter hardness.
This amphiploid is now including in hybridization to wheat for
incorporation the powdery mildew resistance in common wheat breeding
(Spetsov 1990).
T. aestivum x Ae. ovata
A ditelocentric line of 'Chinese Spring' is used in crosses to Ae.
ovata. The amphiploid is genetically unstable, with low
fertility, but possessing fungal resistance and high protein
content.
T. aestivum x Ae. columnaris
The variety 'Chinese Spring' is included in this amphiploid, showing
the same genetic properties as the above mentioned one (Bochev
1988).
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