Clean seed key to prevention
In a rapid response to anthracnose, Western Australian researchers have rated the resistance of different lupin species to the disease.
Anthracnose, a serious disease of lupins, caused by the fungus Colletotrichum gloeosporiodes, was detected in lupin crops in Western Australia and South Australia in September 1996. It has since been found on ornamental lupins i n NSW, Victoria and Tasmania.
Within days of the outbreak, GRDC representatives had met researchers from Agriculture WA and the Centre for Legumes in Mediterranean Agriculture (CLIMA) to look at re-focusing the National Lupin Breeding Program in light of this new and serious threat to the industry.
"The result of this meeting was that we immediately established a disease screening nursery in New Zealand where anthracnose is already widespread. By December, 3,500 different varieties, breeding lines and wild types were sown and inoculated with the anthracnose fungus," said Agriculture WA plant pathologist Mark Sweetingham.
"The first resistance ratings were made in the last week of January. The European White Lupin (L. albus), including the variety Kiev Mutant, has shown up extremely susceptible. Yellow lupins (L. luteus) and narrow-leafed lupins (L. angustifolius) are progressively less susceptible."
Sowing infected seed poses the greatest risk of loss due to anthracnose. European reports indicate that as little as one infected seed in 10,000 can result in severe epidemics under conducive conditions.
"It is early days yet but indications are that useful levels o f resistance exist in certain wild types and some breeding lines of the narrow-leafed lupin. Glasshouse tests in Perth are backing up the preliminary observations," said Dr Sweetingham.
As a result, breeders have some good material to begin the process of producing high-yielding and anthracnose-resistant varieties.
Anthracnose is considered the most important disease of lupins in Europe, North America and South America. The most distinctive symptom is the bending over of stems with a lesion in the crook of the bend. Stem and pod lesions are usually dark brown and elongated with a pale pinkish (sometimes orange) spore mass in the centre. The stem is often completely girdled by these lesions or weakened so that the stem breaks.
Subprogram 2.4.3 Contact: Dr Mark Sweetingham 09 368 3298 or Dr Wallace Cowling 09 368 3258