Diseases
Phytophthora infestans
Late blight is a dangerous disease of solanaceous crops caused by an oomycete, which manifests as the appearance of spots on leaves, stems, and tubers. The development of the disease is triggered by high humidity and moderate temperatures, which can lead to significant crop losses.
Mentioned in descriptions 6 798 varieties reference book.
Affected plants develop dirty-brown spots, often accompanied by a whitish mold on the underside of the leaf, while elongated dark-brown spots appear on the stems. Tubers show hard, sunken brown spots, and the internal tissue exhibits a characteristic rust-brown discoloration upon cutting.
Epiphytotics develop under conditions of high air humidity around 90% and alternating warm days with cool nights. The presence of free moisture, such as dew or fog, is a critical factor for rapid spore germination, which allows the infection to spread across the field in 10–15 days.
In breeding, a distinction is made between specific vertical resistance, controlled by R-genes, and field horizontal resistance, which is considered more reliable due to its polygenic nature and ability to slow down pathogen development. Varieties are evaluated using a 9-point scale; however, the resistance level of the foliage does not always coincide with that of the tubers, requiring comprehensive analysis during variety testing.
Selection based on the description text, not official resistance ratings: such data is not available in registers. Mention indicates that the trait is discussed in the variety's sources; see the variety's profile for details on what is specifically stated.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Shahrokh Khanizadeh
Solanum tuberosum L. · Potato
Landbruks- og matdepartementet, N - 0030 Oslo
Brassica juncea (L.) Czern. · Brown mustard
CREA- CENTRO DI RICERCA PER LE COLTURE INDUSTRIALI (CREA-CI-BO)
Carthamus tinctorius L. · Safflower
Cal West Seeds - Alforex Seeds
Prunus persica (L.) Batsch · Peach
W.Y.MINAMI
Solanum tuberosum L. · Potato
Christoph Gämperli
Prunus amygdalus x Prunus persica
The Regents of the University of California
Solanum lycopersicum L. · Tomato
NIRIT SEEDS
Medicago sativa L. · Alfalfa
Velde Mike John
Allium fistulosum L. · Welsh onion
SEMINIS VEGETABLE SEEDS, NL
Medicago sativa L. · Alfalfa
THE UNIVERSITY OF QUEENSLAND ST. LUCIA CAMPUS
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Vicente Esteban,Manzzioni Ariel,Lado Joanna,Gonz?lez Mat?as,Arruabarrena Ana,Giambiasi Mario
Glycine max (L.) Merr. · Soybean
Syngenta Seeds
Solanum tuberosum L. · Potato
G&C SCHAT - FOBEK
Medicago sativa L. · Alfalfa
Danielson Briggs Gardner
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Whitaker Vance
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Masiá Ciscar S.L.
Solanum tuberosum L. · Potato
Josef Schwarzfischer^^^Adolf Kellermann
Solanum tuberosum L. · Potato
ZPC Portugal
Solanum tuberosum L. · Potato
SIMON BRUNIA
Solanum tuberosum L. · Potato
W. WEIBULL B.V.I.O.
Solanum tuberosum L. · Potato
KWEEKBEDRIJF ROPTA ZPC
Solanum tuberosum L. · Potato
VEREDELINGSBEDRIJF D. BIEMOND B.V.
Solanum tuberosum L. · Potato
S. Meiier B.V.