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English Version:
Arabic Version:
Short communication of practical oriented research/information in agriculture or seed technology are presented in this section
Seed Health Certification in Pakistan
Introduction
In Pakistan, total estimated losses due to plant diseases are about Rs. 3,600
million each year. Loose smut infection in wheat seed lots reduced from 6.9%
in 1984/85 to 0.2-0.5% through seed health certification system in 1992. Losses
due to wheat bunt and loose smut is reported to be Rs.14.4 and 26 million,
respectively in 1971 whereas yield losses due to chickpea blight was US$90
million in 1978 and 1979.
It is reported that 5% tuber infections by potato leaf roll virus reduces potato yield by 13%. Proper seed production by the private sector coupled with free crop inspection and tuber testing services reduced infection of potato seed from 22.2% to 4.5% over ten year period from 1990/91 to 1998/99. In Pakistan, seed health testing was initiated in the 1980s as part of seed certification program and made significant progress.
Production of Healthy
Seed
The list of important seed-borne diseases is given in Table 6. To produce
high quality seed, the following steps are important in the management of
seed-borne diseases.
Location of seed production: The southern parts of the country have comparatively low level of seed-borne diseases. Therefore, R.Y. Khan and Sukkur are the best area to produce healthy seed of cotton and wheat. Seed infected with karnal bunt (Tilletia indica) should not be transported to other areas of the country.
Cropping pattern: Crop sequencing of cotton, sunflower and maize may increase the infection of Macrophomina phaseolina, a common fungal disease of these crops. Including wheat and rice in crop rotation will break the disease disease cycle.
Table 6. List of major seed-borne diseases in Pakistan
| Crop & common name | Casual agent |
| Wheat Loose smut Karnal bunt |
Ustilago tritici Tilletia indica |
| Rice Brown spot Bakanae disease |
Bipolaris oryzace Fusarium monliiforme |
|
Maize
|
F. moniliforme F.graminearum Macrophominaphaseolina Bipolaris maydis |
| Chickpea Ascochyta blight |
Ascochyta rabiei |
| Sunflower Charcoal rot Alternaria leaf spot |
Macrophominaphasealina Alternaria alternata |
| Cotton Bacterial blight |
Xanthomonas campestric pv. malvacearum |
Selection of cultivars: New varieties are screened against a number of important seed-borne diseases. Seed producers are advised to use resistant cultivars to reduce the level of seed-borne diseases.
Field inspection of seed crops: Seed crops must be inspected to determine the level of disease infection. Isolation distance of 10m is suggested, but for loose smut of wheat an isolation distance of 150m is recommended. Annually, 350 to 450,000 acres are inspected including for seed health.
Seed health testing: All 17 seed testing laboratories of the FSCRD carry out visual inspection, purity and germination tests. The Central Seed Health Laboratory is equipped to conduct blotter test, embryo count test and ELISA. All pre-basic and basic seed and 5-10% of certified seed of all crops are tested for seed-borne pathogens.
Seed treatment: Infected seed lots are treated with suitable fungicides before sowing. Regular chemical treatment of pre-basic and basic seed has minimized seed-borne pathogens to its lowest level. Seed health standards for important seed-borne diseases have been notified and lots having high incidence than prescribed limits, are removed from seed production.
Testing imported seed:
Imported seed lots are tested for detection of seed-borne diseases. The FSCRD
has established two seed testing laboratories at Karachi and Lahore port of
entries. These laboratories are being equipped for regular testing of imported
seed consignment against exotic pests. A. Bhutta and A. Hussain, FSCRD,
G-9/4, Islamabad-44000; E-mail: fscd@seed.isb.sdnpk