Nepal
December 22, 2004
On
December 1, CIMMYT handed
over a greenhouse to the Plant Pathology Division of the Nepal
Agricultural Research Council (NARC). Built with the support of
CIMMYT's project on foliar pathogens and funded by Belgian
Development Cooperation (DGCD), this greenhouse will help
sustain research on wheat diseases, despite Nepal's current
social conflict.
At a ceremony in Khumaltar, CIMMYT regional pathologist Etienne
Duveiller delivered the greenhouse keys to T.K. Lama, Chief of
the Plant Pathology Division. The new facility will help NARC
scientists screen for resistance in wheat against yellow rust, a
potentially devastating disease in the hill areas of Nepal.
Grain losses can soar to 30% when early outbreaks occur, as
demonstrated by last year's severe epidemic in parts of the
Kathmandu Valley.
Replacing Outmoded Resistance
Due to the breakdown of resistance in popular varieties like
Sonalika, which date back to the Green Revolution, yellow rust
epidemics have occurred in Nepal since the mid-1980s. In 1997, a
new strain of the rust pathogen became prevalent in the Nepal
hills—a strain that is virulent against Yr9, a gene from rye
that has conferred resistance to yellow rust in many improved
wheats.
To develop disease resistant plants, breeders artificially
inoculate fields of experimental varieties and select the
individuals or families that survive and produce grain. With
help from CIMMYT, advanced lines from Nepal are tested annually
in Pakistan to ensure that promising genotypes are exposed to
new pathotypes of yellow rust from western Asia. But research of
this type in Nepal has suffered in recent years, mainly from a
lack of inoculum to apply to experimental plants. First,
insecurity in Nepal has caused severe financial constraints and
reduced operations for national agricultural research
scientists. Second, there is a lack of proper facilities to
produce rust inoculum for the timely inoculation of breeders'
fields. An alternate approach used—collecting natural inoculum
that survives in off-season wheat crops—became nearly impossible
after a series of dry years eliminated this source of the
pathogen and security restrictions made travel impossible in
remote hilly regions. Finally, less than optimal moisture in the
screening fields of Khumaltar, where the Plant Pathology
Division is located, has necessitated repeated applications of
fresh inoculum.
The timely production of inoculum in the new greenhouse will
improve this situation. This greenhouse has a robust and simple
cooling system to control temperature, as well as a misting
system that guarantees proper humidity. It will allow both
screening against yellow rust under optimal conditions and the
multiplication of inoculum. Since the wheat season is just
starting, researchers working on other diseases and crops will
benefit from having inoculum ready for breeders' plots in
January.
Preserving Spores and Global Partnerships
In
an important recent accomplishment, according to Duveiller (left
on photo), Senior Wheat Pathologist Sarala Sharma was able to
produce fresh inoculum directly from leaf samples collected last
season, using local methods and dried leaves. "This is the first
time that she was able to preserve inoculum from last March,"
says Duveiller. "Yellow rust must be kept alive for
multiplication in the greenhouse and cannot be grown on
artificial media. The main problem is that it is very sensitive
to high temperatures. In Nepal, power failures, poor
refrigeration, and no possibilities of vacuum preservation make
it hard to keep spores."
During the greenhouse opening ceremony, Sharma underlined the
importance of the long-standing collaboration between NARC and
CIMMYT. She acknowledged CIMMYT's continuous support, initiated
by former CIMMYT wheat pathologists Jesse Dubin and the late
Eugene Saari, who encouraged scientists to collect inoculum from
rust-prone areas as a way to record the disease's incidence and
spread. These surveys had continued with support from Duveiller
until recently, when traveling by road became difficult. Also
recognized at the ceremony were the benefits of training on
yellow rust pathotyping that Nepali scientists had received at
IPO-Wageningen, the Netherlands, and Shimla, India.
Similar work may become possible now in Nepal, according to
Duveiller. "This greenhouse, built with Indian technology and
including inexpensive but sturdy polyethylene sheets for siding,
is another example of the importance CIMMYT ascribes to rust
diseases on wheat in Nepal and south Asia," says Duveiller. The
center recently funded the installation of a sprinkler system
for use in disease resistance experiments at Bhairhawa farm in
the Tarai Plains, where the Nepal Wheat Research Program is
based.
The greenhouse handover ceremony was combined with the farewell
party for two NARC pathologists who retired recently, K.
Shrestha and C.B. Karki. A recognized rust pathologist and
longtime CIMMYT friend, Karki received his Ph.D. from Montana
State University and attended the second Regional Yellow Rust
Conference in Islamabad, Pakistan, in March 2004. Dr. K.
Shrestha attended CIMMYT's conference on helminthosporium blight
in Mexico. |