Uganda: early screening for pest resistance in bananas
IITA, iNew
 In
the small tissue culture lab at IITA's Sendusu research station in Uganda,
carrots are on stage – the first stage in a process that should hasten the day
when one of the nastiest pests in bananas will be banished. Thin discs of sliced
carrot are used as a medium to rear thousands of microscopic worms called
nematodes.
In Uganda, where bananas are a food staple, the damage caused by these almost
invisible creatures is incalculable. Banana yields have declined by 50 percent
over the past decades and nematodes are responsible for much of that loss.
Carine Dochez, sponsored by the Flemish Association for Development Cooperation
and Technical Assistance (VVOB), is actually rearing these pests as part of her
work to perfect a rapid technique to evaluate different kinds of banana and
plantain for natural resistance to nematodes.
Finding sources of resistance in the world banana collection is one strategy
for IITA to help banana and plantain farmers in West, Central, and East Africa.
The faster researchers can test the existing world collections of banana
germplasm, the sooner they can develop a solution.
To find resistance, researchers launch a controlled nematode attack or
challenge and wait to see what happens. The attack will do little damage to a
banana with resistance. Current practice is to challenge the complete root
system of a banana sucker with a thousand nematodes and to get good results, you
need to do this with at least eight suckers for each banana type.
In the new technique, just 50 nematodes make the challenge when applied
carefully to each of four of the thin roots that come out of the sucker. Even
though the number of nematodes is low, damage can be assessed after just 8
weeks. Susceptible roots start to rot, and when they are crushed and washed, any
nematodes inside can be easily extracted for counting under a microscope. This
way, many potential candidate bananas can be tested quickly.
The late Dr Paul Speijer, one of three IITA researchers killed in a tragic
airplane crash in January 2000, first proposed the rapid, early screening
technique. Carine Dochez is making sure his work for the farmers of Africa lives
on.
More information:
Article courtesy of i.New, International institute of tropical agriculture (IITA).
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