Yield Losses in Spring Barley Caused by Cereal Aphids (Homoptera: Aphididae) in South Dakota

1986 ◽  
Vol 79 (3) ◽  
pp. 749-752 ◽  
Author(s):  
R. W. Kieckhefer ◽  
B. H. Kantack
1985 ◽  
Vol 57 (2) ◽  
pp. 85-96
Author(s):  
Aarne Kurppa

Soil-borne infection of Bipolaris sorokiniana caused foot and root rot in all spring barley cultivars studied. Significant differences in susceptibility of the cultivars and pathogenicity of the fungus isolates were found. Primary symptoms caused by the fungus were seedling blight, later foot and root rot. Yield losses caused by the fungus varied from 3 % to 33 % the mean being c. 15 %. Yield losses could occur without severe disease symptoms. Toxic metabolites produced by the fungus induced visible foot and root symptoms in all cultivars tested and caused lesions in the leaves of some cultivars. Variability in toxin production of fungus isolates as well as the reaction of a cultivar to toxins was demonstrated. The cultivars most susceptible to soil-borne infection by the fungus also showed the most severe symptoms when exposed to toxic metabolites of the fungus.


1997 ◽  
Vol 90 (5) ◽  
pp. 1346-1350 ◽  
Author(s):  
Todd S. Voss ◽  
Robert W. Kieckhefer ◽  
Billy W. Fuller ◽  
Murdick J. McLeod ◽  
David A. Beck

Author(s):  
Juho Hautsalo ◽  
Fluturë Novakazi ◽  
Marja Jalli ◽  
Magnus Göransson ◽  
Outi Manninen ◽  
...  

AbstractGenome-Wide Association Studies (GWAS) of four Multi-parent Advanced Generation Inter-Cross (MAGIC) populations identified nine regions on chromosomes 1H, 3H, 4H, 5H, 6H and 7H associated with resistance against barley scald disease. Three of these regions are putatively novel resistance Quantitative Trait Loci (QTL). Barley scald is caused by Rhynchosporium commune, one of the most important barley leaf diseases that are prevalent in most barley-growing regions. Up to 40% yield losses can occur in susceptible barley cultivars. Four MAGIC populations were generated in a Nordic Public–Private Pre-breeding of spring barley project (PPP Barley) to introduce resistance to several important diseases. Here, these MAGIC populations consisting of six to eight founders each were tested for scald resistance in field trials in Finland and Iceland. Eight different model covariate combinations were compared for GWAS studies, and the models that deviated the least from the expected p-values were selected. For all QTL, candidate genes were identified that are predicted to be involved in pathogen defence. The MAGIC progenies contained new haplotypes of significant SNP-markers with high resistance levels. The lines with successfully pyramided resistance against scald and mildew and the significant markers are now distributed among Nordic plant breeders and will benefit development of disease-resistant cultivars.


1985 ◽  
Vol 57 (2) ◽  
pp. 97-105
Author(s):  
Aarne Kurppa

Air-borne secondary inoculum of Bipolaris sorokiniana caused severe foliar diseases and yield losses in all 12 spring barley cultivars tested in greenhouses or in the field. For secondary infection to occur a high relative humidity was necessary. Yield losses due to foliar diseases reached a maximum of 43.4 % in greenhouse experiments and 27.8 % in the field. The mean losses were 20.3 % and 12.3%, respectively. Early infection at the time of heading or shortly after it resulted in higher yield losses than did later infection, although the symptom expression was opposite. Spore inoculation or natural secondary infection by the spores from a diseased crop after heading always resulted in a high infection incidence in the grain. Infection incidence as well as fungal invasion of the internal cell leyers of the grains varied significantly among barley cultivars. The most susceptible of those tested were cvs. Teemu, Paavo and Pomo, while the most resistant were Ingrid, Otra and Pirkka.


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