Hamlin
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel 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.
Kiloma
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
6 records
Rumours
ActiveLactuca sativa L. · Lettuce
BEJO ZADEN
NL
5 records
Ralph
TerminatedLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V, Rijk Zwaan Lettuce Breeding department
NL
6 records
Anthem
ActiveLactuca sativa L. · Lettuce
SHAMROCK SEED COMPANY
NL
4 records
Sungari
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Grazion
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Jadigon
TerminatedLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Vizir
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
7 records
Pantlika
ActiveLactuca sativa L. · Lettuce
Syngenta Seeds, NL
NL
6 records
Mehari
TerminatedLactuca sativa L. · Lettuce
Seminis Vegetable Seeds
ES
FR
NL
5 records
Kiari
ActiveLactuca sativa L. · Lettuce
Nunhems B.V.
NL
6 records
Nuria
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
9 records
Dunand
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Fabietto
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
FR
5 records
Campania
ActiveLactuca sativa L. · Lettuce
Enza Zaden (NL)
NL
SI
4 records
Farrio
Application submittedLactuca sativa L. · Lettuce
Syngenta Crop Protection AG
NL
5 records
Skyphos
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Kintelmo
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
7 records
Tallio
ActiveLactuca sativa L. · Lettuce
Syngenta Crop Protection AG
NL
6 records
Fristina
ActiveLactuca sativa L. · Lettuce
Nickerson-Zwaan B.V.
BG
NL
4 records
Stronex
ActiveLactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
NL
6 records
Pelayo
ActiveLactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
NL
6 records
Vulsini
ActiveLactuca sativa L. · Lettuce
Seminis Vegetable Seeds
FR
5 records