Carregon
ActiveLactuca sativa L. · Lettuce
Enza Zaden Seed Operations B.V.
NL
5 records
Diseases
Downy mildew of lettuce
Lactuca sativa L.
A fungal disease of lettuce caused by the obligate oomycete Bremia lactucae, characterized by high pathogen variability and the appearance of chlorotic angular spots with sporulation on the underside of leaves.
In the reference 2 007 varieties crop Lettuce, where this is mentioned in the description.
The disease is caused by the oomycete Bremia lactucae Regel, which exhibits high genetic variability. Pathogen populations include numerous physiological races, designated by the code Bl followed by a sequence number, the composition of which is constantly changing, making it difficult to maintain cultivar resistance.
Symptoms appear as chlorotic angular spots on the upper side of the leaf, restricted by veins. On the underside, a characteristic loose whitish, gray, or violet sporulation layer forms. Affected tissues become necrotic, leading to leaf desiccation and stunted seedling growth.
Breeding for resistance is based on the use of Dm-genes (Downy mildew) and quantitative trait loci (QTL). Cultivar resistance is determined by the ability to withstand specific races of the pathogen; however, the effectiveness of protection is limited due to the ability of local Bremia lactucae populations to overcome genetic resistance.
General information about the subject — on the page Downy mildew.
Varieties of Lettuce mentioned in the description
Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.
Temira
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
6 records
Risonas
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Chalmers
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Salverde
Protection expiredLactuca sativa L. · Lettuce
Harris Moran Seed Company
ES
3 records
Tannin
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer
NL
6 records
Cassini
ActiveLactuca sativa L. · Lettuce
MORAVOSEED
CZ
3 records
Tombelo
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Bolognia
ActiveLactuca sativa L. · Lettuce
Vilmorin-Mikado SAS (FR)
FR
4 records
Gentile
ActiveLactuca sativa L. · Lettuce
Blumen Group, I
IT
3 records
Belicina
ActiveLactuca sativa L. · Lettuce
Syngenta Seeds B.V.
NL
7 records
Kitonia
TerminatedLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
FR
4 records
Laurinas
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
5 records
Tregoney
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
6 records
Olana
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
6 records
Kamikaze
ActiveLactuca sativa L. · Lettuce
Vilmorin-Mikado S.A.S.
FR
4 records
Waterton
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Greco
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
6 records
Comedion
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
FR
4 records
Frecciarossa
ActiveLactuca sativa L. · Lettuce
MARALDI SEMENTI S.r.l.
IT
4 records
Joice
ActiveLactuca sativa L. · Lettuce
BEJO ZADEN
NL
9 records
Optima
Application submittedLactuca sativa L. · Lettuce
Vilmorin, S.A.
FR
4 records
Kirinia
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
FR
4 records
Golia
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
5 records