We hybridized 2 octoploid species (2n=8x=40)
T. aureliis and
T. cuneiformis and one hexaploid species (2n=6x=30),
T. orientalis. One octoploid (2n=8x=40) and 2 heptaploid (2n=7x=35) hybrids were obtained. The hybrids were studied cytologically to determine their genomic relationships. Meiotic behavior in the
T aureliis×
T. cuneiformis hybrid was very irregular, with numerous laggard chromosomes and bridges in AI and AII. Mean pairing relationships were 10.10 I, 13.80 II, 0.53 III and 0.13 IV. All cells of
T. aureliis×
T. orientalis had 5 I+15 II, while
T. cuneiformis×
T. orientalis presented irregular meiosis, with mean pairing relationships of 4.86 I, 14.86 II and 0.13 III. The genome constitution of
T. aurelii is A
aA
aA
oA
oBBB
oB
o and of
T. orientalis is A
oA
oBBB
oB
o. On the basis of the chromosome associations in the hybrids, we propose the genomic formula A
cuA
cuA
oA
oBBB
oB
o for
T. cuneiformis. The 3 genomes of
T. orientalis are similar to 3 of the 4 genomes of
T. aureliis and
T. cuneiformis. The 2 latter species show also 3 common genomes and the fourth one is homoeologous.
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