New Romaine Lettuces Resist Dieback
Disease By Marcia
April 10, 2003
It's the crisp, crunchy romaine lettuce that makes a Caesar
salad so appealing. Romaine lettuce is also perfect for adding to other mixed
greens. And what better natural, edible utensil for scooping up a creamy dip
than the small, firm inner leaves of this lettuce?
But today's commercially grown romaine is vulnerable to what's
known as lettuce dieback disease. The disorder, which can easily devastate
entire fields of this popular lettuce, is caused by one or more soil-dwelling
Tombusviridae viruses. These include lettuce necrotic stunt virus, and
tomato bushy stunt virus. Lettuce dieback disease doesn't afflict
crisphead--also known as iceberg--lettuce or certain leaf lettuces.
Two Agricultural Research
Service plant geneticists have now bred what are apparently the first
parent romaine lettuces that are resistant to these pernicious plant viruses.
Edward J. Ryder and colleague Rebecca C. Grube developed the three novel
lettuces, known as 01-778M, 01-781M and 01-789M, at the agency's U.S.
Agricultural Research Station in Salinas, Calif.
These lettuces result from about three years of research and
testing in both infested and disease-free fields at Salinas and two other
coastal California sites. The scientists noted that the lettuces have not yet
been tested in other regions of California or Arizona where romaine lettuce is
Small supplies of the seeds of the new lettuces are available to
plant researchers and breeders.
Ryder and Grube will discuss their research today with visitors
at the research station's daylong Open House. Other Salinas scientists from
ARS, the University of California at
Davis, and the Artichoke Research Association also will describe their
experiments for the guests.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.