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Wheat Information
Service
Number 72: 84 (1991)
The
difference of genes responsible for homoeologous pairing induction
between Aegilops speltoides and Ae. sharonensis
and its evolutionary significance
Junichi Sano
Laboratory of Technology, Faculty of Education, Miyazaki
University, Gakuen-kibanadai-Nishi, Miyazaki, 889-21, Japan
The aims of the present investigaion were to analyze the genetic
difference between two closely related diploid species Aegilops
speltoides and Ae. sharonensis concerning homoeologous
chromosome pairing induction in hybrids with tetraploid wheat and to
determine whether the Ae. speltoides genome was homologous
with the B genome of tetraploid wheat. For these purposes these two
Aegilops species were crossed to each other. The F1
hybrids showed nearly normal meiotic pairing and were further crossed
with tetraploid wheat. The resulting triploid progeny was analyzed
cytologically and morphologically. The amount of chromosome pairing
segregated in a 3 : 1 ratio of a high pairing class versus a low
pairing class. These two classes were corresponded to the classes
caused by the parental Aegilops species. Intermediate classes
or classes outside the range of the parents were not found. Because
the present Ae. sharonensis strain caused little or no
homoeologous pairing and its genome is not homologous with the B
genome of tetraploid wheat, it was concluded that homeologous pairing
induction was controlled by two duplicate and equally potent genes of
Ae. speltoides segregation independently and that the Ae.
speltoides genome was also not homologous with the B genome of
tetraploid wheat. It was shown by morphological analysis that one of
these genes was linked to a gene which controlled spike
disarticulation.
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