Indian Society of Genetics & Plant Breeding

CHROMOSOME PAIRING IN TWO SESQUIPLOID HYBRIDS AND ITS BEARING ON GENOME RELATIONSHIP IN THE GENUS SESAMUM

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THE incorporation of desirable genes from wild relatives into cultivated species is often
hindered by the sterility incidental to such wide crosses. While this obstacle can be
overcome by the induction of amphiploidy, the amphiploids themselves are not directly
useful, in as much as they possess a complex of undesirable characters contributed by
the wild parent.
It becomes necessary, therefore, to backcross the amphiploid,
with proper selection, to the cultivated parent. The successful transference of the
desired character, carrying as few of the undesirable genes of the wild relatives as
possible, depends on the extent of intergenomic pairing that occurs in the sesquiploid
and later generations. The study of the cytology of the sesquiploids, as also of the later
generations is, therefore, of great importance in evaluating the potentialities of wide
crosses. In addition, such
s~squiploids can become a source of new numerical and
genic constitutions that can, by subsequent autoploidy, result in variation leading
to further differentiation (Goodspeed, 1954).
  

Info

Year: 1959
Volume: 59
Issue: 2
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906

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