Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
An Overview on Seed-borne Diseases and Effective Protection against
Them
Karuna Vishunavat
Department of Plant Pathology, G.B.P.U.A&T., Pantnagar- 263 145 (UK)
There are two ways for improving the output of food production:
1. Increase productivity
2. Avoid crop failures
This duality hold true, in particularly in relation to the fundamental demand for better seed.
For food sufficiency India underwent introduction of new crops or high yielding varieties of
indigenous planting material, particularly the seed. Of course, it helped India to sustain its food
security via green revolution but at the same time there had been challenges of introduction of
many seed-borne plant pathogens which later established or posed problems time to time for
successful crop production.
Pathogens thus, introduced remained confined to some regions initially, but later spread all
over the country. The diseases which used to be of minor importance became the major diseases
in the regions where pathogen established and disseminated.
There have been the evidences that the infected or contaminated seeds at an early stage
can lead to proliferation of microorganisms through out crop production leading to substantial crop
losses an at times to epidemic proportion. Thus, the seed which is the key input for all crop
cultivation has the potential for trans-boundary spread of plant diseases and serves as primary
source of inoculum for disease epidemics.
Seeds are both the vectors and victims of diseases. Over the years, there has been a long
list of seed-borne pathogens which have been intercepted during cross boundary trade by NBPGR
in India through seed or planting material. With the movement of seed, which is often produced in
one country, processed and packaged in a second and sold and planted in another, comes an
increasing danger of the spread of seed-borne diseases.
It is estimated that 30% diseases are of seed borne nature and can be managed through
disease-free seeds. The losses due to seed-borne diseases in developing countries are estimated
to be 60-80% higher than in industrialized countries. Conservatively estimated, seed-borne
diseases cause losses in the order of 50 million ton of food annually.
Impact of poor seed health/ seed borne pathogens
• Leads to poor seed germination to various degrees,
• give rise to pre- and post emergence seedling mortality and progressive disease
development in the field and thereby reduces the yield and quality of the crop
• contaminate previously disease-free areas,
• spread of the diseases across national or international boundaries,
• reduce shelf life of the seed, and
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