Rome, Italy
June 26, 2007
Pollen and pollinators could play
a much more important role in the conservation of crop
diversity, Dr Jan Engels, a senior scientist at
Bioversity
International, today told the
9th
International Pollination Symposium in Ames, Iowa, USA.
"People are used to the idea of long-term storage of seeds in
genebanks," Engels said, "but we could also store pollen, and
that would be very useful."
At present pollen is sometimes stored for relatively short
periods so that researchers can make use of it in breeding
programmes. It is also a good form in which safely to transport
genetic diversity around the world, because few diseases are
transmitted through pollen. Engels and co-author Dr Ehsan
Dulloo, suggest that it would be ideal to store pollen as well
as seeds.
Dulloo, an expert on genebank storage, explains that not all
plants have seeds that can be dried and cooled for storage "Some
are recalcitrant," he said, "meaning we have to find other ways
to store them. Some pollen is recalcitrant too and cannot be
stored. But there is no correlation between recalcitrant seeds
and recalcitrant pollen, so long-term storage of pollen offers a
complementary approach to the conservation of plants with
recalcitrant seeds."
Of course there are disadvantages; pollen carries only the male
part of the genome, and it can be difficult to collect. But the
benefits for rational conservation of crop diversity are great.
"The other area where we really need pollen is in-situ
conservation and the conservation of crop wild relatives," adds
Engels. “But really, it is the pollinators we need.”
In-situ conservation takes place in farmers' fields and
surrounding areas and complements ex-situ storage in genebanks.
It allows plants to continue to interact with their environment
and thus allows their genes to continue evolving and adapting to
changed circumstances.
"Without the right pollinators, crops and wild relatives are not
going to make nearly as many seeds, threatening their survival,"
Engels said. “We have to maintain a diversity of other plants in
the vicinity to provide pollinators with alternative food
sources and other requirements.” Because it supports
pollinators, high local diversity has also been shown to improve
the productivity of agricultural crops, such as coffee in Costa
Rica and papaya in Kenya.
Pollinators are also vitally important for ex-situ collections.
When genebank managers need to regenerate samples in store they
rely on pollinators to maintain the genetic diversity of
cross-pollinated species.
Engels is hopeful that researchers will respond to the
interdisciplinary challenge of investigating and making more use
of pollen and pollinators to improve long-term conservation of
useful plant diversity. |
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