Diseases
Alternaria
Alternaria blight is a complex of fungal diseases characterized by the appearance of dark spots with concentric zonation on plant organs. The disease leads to tissue necrosis, a reduction in photosynthetic activity, and significant yield losses.
Mentioned in descriptions 2 812 varieties reference book.
Alternaria blight manifests as dark, brown, or black spots that often have a characteristic concentric pattern resembling a target. On leaves, the spots eventually coalesce, causing necrosis, while on stems and fruits, depressed areas form, which, in conditions of high humidity, are accompanied by a velvety olive-colored sporulation coating.
Disease development is most intense at temperatures from +20 to +30°C and high air humidity, including the presence of free moisture. The risk of infection increases significantly with dense planting, mechanical tissue damage, and mineral nutrient deficiencies, as the pathogens often act as a secondary infection attacking weakened plants.
Varietal resistance to Alternaria blight is achieved through a combination of passive barriers, such as tissue structure features, and active responses, such as hypersensitivity, which blocks pathogen development. Resistance evaluation of varieties in breeding is conducted through field trials on natural infestation sites and provocation methods using artificial inoculation, which allows for the differentiation of varieties by the degree of infection.
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.
Brassica napus L. · Rapeseed
STELLING DIETER
Helianthus annuus L. · Sunflower
Jean Pierre Dufourcq
Brassica napus L. · Rapeseed
PIONEER OVERSEAS CORPORATION
Brassica napus var. napus · Rapeseed
KWS, D
Brassica napus var. napus · Rapeseed
Hodowla Roslin Strzelce Sp z.o.o. Grupa IHAR
Brassica napus var. napus · Rapeseed
Dirk Decherf
Cucumis melo L. · Melon
PETOSEED CO
Solanum lycopersicum L. · Tomato
SAKATA SEED AMERICA INC US
Solanum lycopersicum L. · Tomato
IP MASHTAKOV ALEKSEJ ALEKSEEVICH
Solanum lycopersicum L. · Tomato
HEINZSEED
Solanum lycopersicum L. · Tomato
HEINZSEED
Citrus xtangelo J. W. Ingram & H. E. Moore · Tangelo
Jude W. Grosser^^^William S. Castle^^^Frederick G. Gmitter Jr.
Citrus clementina hort. ex Tanaka · Clementine
ALIZA VARDI
Solanum lycopersicum L. · Tomato
UNITED GENETICS SEEDS CO
Solanum lycopersicum L. · Tomato
UNITED GENETICS SEEDS CO
Citrus L. · Citrus
THE AGRICULTURAL RESEARCH
Solanum tuberosum L. · Potato
Vaccinium corymbosum L. · Highbush blueberry
Daucus carota L. · Carrot
Brassica napus var. napus · Rapeseed
Brassica napus var. napus · Rapeseed
Solanum tuberosum L. · Potato
Hybrids between Citrus reticulata Blanco and Citrus sinensis (L.) Osbeck · Orange
Pyrus pyrifolia (Burm. f.) Nakai · Japanese pear