Rosalo
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
7 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.
Xamena
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
7 records
Claragio
ActiveLactuca sativa L. · Lettuce
Syngenta Seeds B.V.
NL
8 records
Arletti
ActiveLactuca sativa L. · Lettuce
Vilmorin, F
FR
5 records
Melosa
ActiveLactuca sativa L. · Lettuce
Nunhems, NL
NL
9 records
Cencibel
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Orakio
ActiveLactuca sativa L. · Lettuce
Syngenta Crop Protection AG
NL
5 records
Ice Callas
Application submittedLactuca sativa L. · Lettuce
Syngenta UK Ltd
NL
7 records
Crispol
ActiveLactuca sativa L. · Lettuce
Nunhems B.V., Nunhems B.V.
NL
7 records
Bobal
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Top Gun
Application submittedLactuca sativa L. · Lettuce
Seminis Vegetable Seeds
NL
4 records
Betanto
TerminatedLactuca sativa L. · Lettuce
NUNZA B.V.
NL
5 records
Bonarda
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
8 records
Manolis
ActiveLactuca sativa L. · Lettuce
Bejo Zaden B.V.
NL
7 records
Romai
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan, NL
NL
8 records
Favola
TerminatedLactuca sativa L. · Lettuce
SYNGENTA SEEDS B.V.
ES
NL
8 records
Vilar
Application submittedLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Business
ActiveLactuca sativa L. · Lettuce
BEJO ZADEN
NL
5 records
Telex
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Dragone
ActiveLactuca sativa L. · Lettuce
Vilmorin-Mikado S.A.S.
FR
6 records
Feddenas
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan, NL
NL
7 records
Jara
ActiveLactuca sativa L. · Lettuce
Victor Segura Juan
NL
7 records
Xanadu
ActiveLactuca sativa L. · Lettuce
ENZA ZADEN
NL
4 records
Kiambi
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records