Untitled - International Rice Research Institute

Seed health management for crop production
In tropical Asia, the productivity of newly released
modern rice cultivars declines rapidly because of
seed health problems associated with the continuous
use of the seed without adequate seed health management.
At IRRI, we have conducted research on
seed health management since the early 1990s. The
research effort has focused on understanding farmers’
seed health problems in relation to crop management
and production. By improving farmers’ seed
health management, rice yield could be increased by
5–20%. Increasing farmers’ yields generates more
income and profit. The marginal cost-benefit ratio
was estimated at 5, and even 10, depending on the
quality of the farmers’ original seed stock for planting
(T.W., unpubl. data).
Seed health management is an important way of
reducing pest damage and weed infestation in the
field. By employing sound seed health management,
farmers not only minimize the use of harmful agrochemicals,
they also maximize the genetic yield potential
of these modern rice cultivars. We found that
the productivity of foundation seed is reduced by 1 t
ha –1 in three crop seasons using current farmers’
seed health management practices (L. Diaz, M.
Hossain, V. Merca, and T.W. Mew, unpubl. data).
Yield changes according to the level of “high-quality
seed” in seed stock used by farmers. When the level
of high-quality seed reached 90% of the seed stock
for planting, the yield increase was not significant.
In rice seed health testing, little information exists
on pathogen detection frequency on seed and on
which part of the seed an organism is likely to be
located. This handbbok contains information on rice
seed health testing that we have been carrying out for
the past 20 years. We hope to offer seed health testing
technicians, college or graduate students, and
teachers in plant pathology or seed technology a useful
guide. Information on seed health testing can also
be an important means of improving crop production
practices of farmers. The information contained in
this handbook is based on IRRI’s rice seed health
testing activities on both incoming and outgoing
seeds. Thus, the material provides a reference for
many seed health testing laboratories. In view of the
increasing interest in international trade in rice, the
handbook also serves as a basis for establishing plant
quarantine guidelines for individual countries.
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