New Peas Unfazed by Viral Bully
By Jan Suszkiw
December 3, 2009
Four advanced dry pea breeding lines
that tolerate the pea enation mosaic virus (PEMV)a scourge of
Pacific West pea cropshave been identified by
Agricultural Research Service (ARS)
Use of the breeding lines PS08-39, -41, -68 and -76 to develop new
commercial cultivars could give growers added insurance against PEMV.
Currently, there are no PEMV-resistant dry pea cultivars. The few fresh pea
cultivars that are resistant all contain the same single dominant genethe
En genefor resistance, raising concern the virus could quickly
evolve virulent new forms to overcome it, note
Porter, plant pathologists with the
Vegetable and Forage Crops Research Laboratory in Prosser, Wash.
The PS08 lines, however, somehow tolerate the virus presence, even at
high concentrations, without sustaining significant damage, loss of growth or
seed yield. Because of this plant- pathogen truce, PEMV may be less
apt to turn more virulent than it would with resistant varieties. Plus, the
resistance-conferring En gene may cause yield drag, whereby
the plants lose some of their yield at the expense of viral protection.
PEMV is transmitted to peas, as well as to chickpeas and other legumes, by
aphid feeding. But spraying insecticide to prevent such feeding isnt
always effective. In affected plants, PEMV disease symptoms include stunted
growth, translucent veins, blisterlike lesions, deformed pods and reduced
However, in field tests at Corvallis, Ore., and in greenhouse tests at
Prosser, the PS08 lines sustained their growth and yield despite infection by
the virus, reports Larsen. He and Porter presented a poster paper on their
findings at the American Phytopathological
Societys annual meeting in August in Portland, Ore.
In related work, Larsen and ARS colleague
Coyne at Pullman, Wash., teamed with researchers in New Zealand to show
that PEMV is not seed-transmitted in pea, correcting an earlier published
report that has resulted in costly testing of pea exports to the island
country, a key winter seed increase nursery for U.S. seed companies.
ARS is the U.S. Department of
Agricultures principal intramural scientific research agency. The
research supports the USDA priority of promoting international food security.