The present understanding of the genetic control of flowering in
wheat
is reviewed. Although this information will
continue to be of value in breeding and in recognizing the role such genes
have
had in adapting the wheat crop
to global agriculture, its use in defining the processes responsible for
flowering will be limited. Progress here will
depend on developments in model plant systems such as Arabidopsis,
where methods for isolating genes are much
more advanced than in wheat. These developments, which have already started,
will probably be used to establish
homologies between the genes for flowering within the cereals, as well
as
more widely. An understanding of the
flowering process in wheat is likely to emerge from this approach. In the
meantime, there are some unknowns in
the genetics of flowering in wheat which need to be resolved. These include
the identification of a gene(s) on the
group 4 chromosomes of wheat which is homoeoallelic with the gene Sh
in barley. Also, the proposed gene(s)
delaying flowering and located on the group 6 chromosomes needs to be
recognized and mapped. Similar needs
occur for the group 1 chromosomes as well as the resolution of whether
or not
Vrn5 is correctly positioned on chromosome 7BS.