Thespian
ActiveLactuca sativa L. · Lettuce
NUNHEMS
NL
10 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.
Sunny
ActiveLactuca sativa L. · Lettuce
Nickerson Zwaan, NL
CZ
HU
NL
SK
9 records
Sementel
ActiveLactuca sativa L. · Lettuce
Bejo Zaden, NL
NL
8 records
Pia
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan (NL)
CZ
HR
HU
NL
SI
SK
7 records
Maritima
ActiveLactuca sativa L. · Lettuce
Enza Zaden, NL
HR
NL
10 records
Lirice
ActiveLactuca sativa L. · Lettuce
Vilmorin, F
FR
HR
8 records
Iglo
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
CZ
NL
SK
10 records
Grewger
ActiveLactuca sativa L. · Lettuce
Syngenta Crop Protection AG
NL
12 records
Grandolia
ActiveLactuca sativa L. · Lettuce
Nunhems, B.V.
NL
9 records
Gaugin
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V. (NL)
HR
NL
12 records
Expertise
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
10 records
Experience
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
10 records
Excite
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
10 records
Crunchita
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V, Rijk Zwaan Lettuce Breeding department
NL
9 records
Coolguard
ActiveLactuca sativa L. · Lettuce
Seminis Vegetable Seeds
ES
IT
SI
9 records
Cook
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
9 records
Challenge
ActiveLactuca sativa L. · Lettuce
Zaadunie B.V.
CZ
ES
NL
11 records
Campionas
ActiveLactuca sativa L. · Lettuce
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL B.V.
CZ
NL
8 records
Auvona
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
10 records
Zeralda
ActiveLactuca sativa L. · Lettuce
Vilmorin, F
FR
HR
8 records
Xerafin
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
8 records
Wintex
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
9 records
Tudela
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
ES
NL
7 records
Triathlon
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
FR
HR
8 records