16 June 1995

Weed genetics vacuum

UNRAVELLING genetic variability in weeds is a big challenge for researchers aiming to help growers achieve good field control, according to Rothamsteds George Cussans.

Changes in the speed at which blackgrass develops resistance to different chemicals according to site shows there is still much to learn, he told ARIA members in a paper just before his retirement.

The extent to which various perennials like onion couch reproduce from seed also needs much more investigation. "It only needs one successful seeding every few years to keep a population going and to maintain genetic diversity.

"And is the chickweed that germinates at Christmas the same stock that germinates in the spring? We just dont know. Theres an awful lot to do."