NARCISSUS CERTIFICATION IN SCOTLAND

Narcissus production in Scotland is centred in the north-east coastal area of the country mainly in the Grampian Region.
The area has important natural advantages for narcissus bulb production – suitable soil types and a favourable climate.
Narcissus are grown on large arable farms which allow a long rotation between crops.
In the cool climate virus spread in stocks is extremely slow.
The incidence of the important narcissus pests and diseases eg stem and bulb eelworm Ditylenchus dipsaci and basal rot – Fusarium oxysporum f. sp. narcissi is very low.

In response to a request from growers in the area a certification scheme for commercial stocks, based on visual inspection and rogueing, was introduced in 1969. Tolerance levels were set for obvious virus, pests and diseases.
This scheme has been successful for several cultivars, and stocks of sufficiently high health standard for export are regularly produced.
However, several viruses infect narcissus without causing obvious symptoms or produce symptoms only very late in the season.
Furthermore because of substantial virus infection certain cultivars were unable to achieve certification.
Consequently in 1972 a project was started to obtain and propagate virus free plants of commercially important cultivars, and to introduce these to the industry together with a certification scheme for Virus Tested stocks.

In 1976 the first virus free stocks were introduced to the industry and the Foundation Stock Scheme was initiated.
Commercial propagation is performed in two stages under strictly controlled conditions prescribed by the Department of Agriculture and Fisheries for Scotland.
In the first stage which lasts for 3 years twin scalling is used for rapid multiplication and the stocks are grown in vector proof structures in sterilized soil.
In the second stage – field propagation the following requirements are laid down in respect of isolation and site suitability.

Proposed sites must:

1. have no previous history of narcissus cropping

2. be at least 500 metres from commercial narcissus crops

3. be sampled and tested to ensure relative freedom from virus vector nematodes

4. be free from detectable soil borne virus

5. be fumigated with dichloropropene.

Growing crops are inspected twice during the growing season to ensure freedom from virus infection, pests and diseases.

At present 18 Foundation Stocks comprising 5 cultivars are growing at 6 different field sites.

IV International Symposium on Flower Bulbs

P.A. Rankin

https://doi.org/10.17660/ActaHortic.1986.177.94