Hormones that "wake up" dormant tubers
IITA, iNew
 Only
patience could make yams ready for planting, until IITA researchers found that
the same chemical solution used to make poinsettia plants shrink can make yams
grow. They have identified a hormone that can “wake up” dormant tubers and
accelerate propagation cycles of this vital food source.
Yam is the dominant food crop in West Africa, but unlike other staple crops
such as cassava, most yam varieties can only be harvested once annually, even
though they mature in as few as 8 to 10 months even teve. New plants are usually
grown using seed yams from the previous year's crop but this takes time. After
being harvested, the tubers lie dormant for three months before sprouting; and
until the yams sprout, they won't grow into new plants. This awkward growing
cycle means farmers all produce at the same time, glutting the market for a few
months until the supply runs out and prices skyrocket.
While improved yam propagation methods exist, changing the growing cycle
remains a challenge. Previous research showed that a growth regulating plant
hormone called gibberellin could increase yam dormancy time for food storage
purposes. So an IITA scientist, whose work is funded by the Japanese Ministry of
Foreign Affairs, tried the reverse. He treated tubers with a solution containing
gibberellin inhibitors, which was already manufactured for creating dwarf-sized
versions of plants such as poinsettias and strawberries. The results were
groundbreaking. Using select water yam varieties, he found that soaking the
tubers for 24 hours reduced dormancy time from three months to just a single
month.
“The power to induce sprouting in dormant yam opens up many possibilities,”
says IITA yam physiologist Dr Hironobu Shiwachi. “This means we can change the
growing period to meet market demand and can more easily disseminate improved
varieties.”
With sufficient water supply, yam can now be grown twice a year.
Additionally, field tests in Nigeria have shown that there is potential in
certain areas for crop rotation with rice. Off season yam cultivation will help
reduce market fluctuations, ensuring better prices for farmers and more yams for
all West Africans.
More information:
Article courtesy of i.New, International institute of tropical agriculture (IITA).
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