EFFECT OF LONG-TERM CONTINUOUS CROPPING OF SPRING WHEAT ON AGGRESSIVENESS OF Cochliobolus sativus

1989 ◽  
Vol 69 (2) ◽  
pp. 395-400 ◽  
Author(s):  
H. M. EL-NASHAAR ◽  
R. W. STACK
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Wheat Root ◽  
Cochliobolus Sativus ◽  
Continuous Cropping ◽  
Surrounding Area ◽  
Helminthosporium Sativum ◽  
Wheat Plot

Cochliobolus sativus cultures were collected from symptomatic wheat plants from a plot planted continuously to wheat for over 90 yr and from symptomatic wheat plants in commercial grain fields cropped rotationally in the surrounding area. Pathogenicity of these isolates was tested in replicated greenhouse trials using wheat plants scored for disease 6 wk after inoculation. Isolates from the continuous-cropped wheat plot were more aggressive on average than were isolates from commercial fields. Long-term continuous cropping to wheat appears to shift the population of C. sativus toward more aggressive types, although many less aggressive types also remain.Key words: Aggressiveness, Drechslera sorkiniana, Helminthosporium sativum, wheat root rot

scholarly journals Taxonomic composition and incidence of phytopathogenic fungi on the roots of soft spring wheat in the Kansk-Krasnoyarsk forest-steppe

2021 ◽  
Vol 2 (44) ◽  
pp. 22-22
Author(s):  
Alexander Saakian ◽  
◽  
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Bipolaris Sorokiniana ◽  
Triticum Aestivum L ◽  
Wheat Root ◽  
Phytopathogenic Fungi ◽  
Taxonomic Composition ◽  
Forest Steppe ◽  
Root Infection ◽  
Fusarium Spp

The taxonomic composition and incidence of phytopathogenic fungi on the roots of soft spring wheat Triticum aestivum L. of nine varieties of Siberian origin (Altayskaya 70, Altayskaya 75, Krasnoyarskaya 12, Novosibirskaya 15, Novosibirskaya 16, Novosibirskaya 29, Novosibirskaya 31, Novosibirskaya 41 and Svirel) cultivated using wheat and fallow as a predecessor, was studied in the area of Kansk-Krasnoyarsk forest-steppe. Average incidence of fungal root infection was 24%. In plants grown using wheat as a predecessor, the incidence was statistically significantly (p <0.05) higher than in plants grown using fallow as a predecessor (27.3 versus 20.6%). Statistically significant (p <0.05) differences in the prevalence of root infection were revealed between cultivars. The maximal prevalence (33.3 and 32.3%, respectively) on average for the wheat predecessor and fallow was found for the varieties Svirel and Altayskaya 75, the minimal (16.7%) for the varieties Novosibirskaya 16 and Altayskaya 70. The complex of phytopathogenic fungi on the roots is represented by Fusarium spp., Bipolaris sorokiniana and Alternaria spp. (31.4, 44.9 and 23.7% of the pathogenic complex on average for varieties and variants, respectively). The composition of pathogens statistically significantly (p <0.01) depends on the predecessor. In the plants cultivated using wheat as a predecessor, the proportion of Alternaria spp. was higher whereas proportions of Fusarium spp. and Bipolaris sorokiniana were lower. No differences in prevalence and taxonomic composition of root infection between varieties originated from Novosibirsk territory, Krasnoyarsk territory and Altay territory were found. Keywords: SPRING WHEAT, ROOT ROT, KRASNOYARSK TERRITORY, FUSARIUM SPP., BIPOLARIS SOROKINIANA, ALTERNARIA SPP

THE USE OF WATER BY WHEAT PLANTS WHEN INOCULATED WITH HELMINTHOSPORIUM SATIVUM

1940 ◽  
Vol 18c (5) ◽  
pp. 178-198 ◽  
Author(s):  
B. J. Sallans
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Marked Reduction ◽  
Dry Matter ◽  
Severely Injured ◽  
Light Conditions ◽  
Water Requirements ◽  
Stages Of Growth ◽  
Early Stages ◽  
Helminthosporium Sativum

The transpirational histories of wheat plants, inoculated with Belminthosporium sativum Param., King & Bakke to produce root rot, showed a marked reduction in water loss during the early stages of growth, when compared with uninoculated plants. This was accompanied by a corresponding reduction in the transpiring areas owing to reduced lengths and widths in the second, third, and fourth leaves to appear. As the plants entered into the early stages of elongation of the culm the transpirational story reflected a recovery in the inoculated plants. The later leaves to appear were longer with greater transpiring areas than in uninoculated plants. This fact combined with the death of the first three or four leaves resulted in greater transpirational and photosynthetic areas in the inoculated plants with consequent increased yields of dry matter. Probably similar recovery does not occur under competitive field conditions, where weeds and healthy wheat plants are present. Poor light conditions and low soil moistures were not conducive to recovery of inoculated plants. The water requirements of wheat did not appear to be affected significantly by inoculation. Of two varieties of spring wheat, Reward was more severely injured initially and recovered more rapidly than Marquis. Several possible explanations of the recovery recorded here are discussed.

The effect of soil salinity on common root rot of spring wheat and barley

1993 ◽  
Vol 73 (1) ◽  
pp. 323-330 ◽  
Author(s):  
L. J. Duczek
Keyword(s):  
Spring Wheat ◽  
Soil Salinity ◽  
Root Rot ◽  
Salinity Gradient ◽  
Cochliobolus Sativus ◽  
Liquid Media ◽  
Common Root ◽  
Inoculum Level ◽  
Common Root Rot ◽  
The Relationship

Samples were taken from several sites across a salinity gradient from areas where plants were visibly unaffected to the edge of saline areas where no plants grew, from commercial fields located near Saskatoon in 1984, 1987, 1990 and 1991. There was a significant (P = 0.05) positive correlation for wheat and barley between salinity and common root rot in all years, except 1991 (1984: r = 0.445, n = 26; 1987: r = 0.390, n = 54; 1990: r = 0.244, n = 75; 1991: r = 0.247, n = 40). The correlation between inoculum level and disease was not significant, except for one barley field in 1990. However, when inoculum level was used as a covariate, the significance of the relationship between salinity and common root rot increased. Growth of Cochliobolus sativus was unaffected on solid and liquid media until conductivity levels were higher than 30–50 mmhos cm−1. Since wheat and barley do not grow at levels higher than 10–15 mmhos cm−1, salinity would have a greater affect on plants than on the pathogen. The relationship between salinity and disease is consistent with the theory that stress increases common root rot in plants. However, the variation in salinity only explains about 20% of the variation in common root rot. Key words: Cochliobolus sativus, common root rot, salinity, cereals

scholarly journals Response of wheat root pathogens to crop management in eastern Saskatchewan

2007 ◽  
Vol 87 (4) ◽  
pp. 953-963 ◽  
Author(s):  
M. R. Fernandez ◽  
P. Basnyat ◽  
R. P. Zentner
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Soil Tillage ◽  
Cochliobolus Sativus ◽  
Oilseed Crop ◽  
Relative Role ◽  
Common Root ◽  
Common Root Rot ◽  
Previous Crop ◽  
Tillage System

A survey of common root rot in spring wheat (Triticum aestivum L.) and durum wheat (T. turgidum L. var. durum) crops was conducted in eastern Saskatchewan from 1999 to 2001 to investigate the association of agronomic practices with disease and fungal populations, in particular Fusarium species associated with Fusarium head blight (FHB), which is a disease of increasing importance in this region. Spring wheat preceded by summerfallow, or grown after a sequence that included summerfallow and a cereal crop, had increased levels of Cochliobolus sativus and lower levels of most Fusarium spp. in discoloured subcrown internodes. Cropping sequences that included at least one noncereal crop in the previous 2 yr resulted in higher percentage isolations of F. avenaceum and F. graminearum than sequences which did not include noncereal crops. Highest levels of F. avenaceum, the most common FHB pathogen in the province, were observed when the previous crop was a pulse. Tillage system effects depended on the previous crop. When wheat was preceded by an oilseed crop, C. sativus decreased as the number of tillage operations decreased, whereas F. avenaceum and M icrodochium bolleyi increased with a reduction in tillage. Associations of fungal isolations with previous glyphosate use were negative for C. sativus and positive for F. avenaceum and M. bolleyi, although these effects varied depending on tillage system. Increased levels of important Fusarium pathogens were thus associated with current trends in production practices, namely continuously cropped diversified rotations and less reliance on mechanical soil tillage. Further investigation into the relative role of tillage intensity and glyphosate use versus cropping sequence on Fusarium populations in underground wheat tissue is needed. Key words: Common root rot, wheat, Cochliobolus sativus, Fusarium, tillage, glyphosate, crop rotation, nitrogen

ROLE OF CHROMOSOME 5B IN CONTROLLING BLACK POINT INCIDENCE IN HARD RED SPRING WHEAT

1989 ◽  
Vol 69 (3) ◽  
pp. 675-679 ◽  
Author(s):  
R. L. CONNER ◽  
E. D. P. WHELAN
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Cochliobolus Sativus ◽  
Recessive Trait ◽  
Substitution Lines ◽  
Black Point ◽  
Hard Red Spring Wheat ◽  
Chromosome 5B ◽  
Or Genes ◽  
Spring Wheat Cultivar

Tests of several wheat (Triticum aestivum) cultivars against Cochliobolus sativus, a causal agent of black point, showed that black point incidence was lowest in Cadet, intermediate to high in Apex, and highest in S-615 and Rescue. Inoculation of disomic substitution lines for chromosome 5B demonstrated that black point incidence in Cadet is controlled by a gene or genes located on chromosome 5B. The F1 progeny from crosses between Cadet and Rescue had a black point incidence similar to that of Rescue, indicating that resistance is a recessive trait. Resistance to black point and common root rot was not related since the moderately root rot resistant cultivar Apex did not consistently have a lower incidence of black point than the root-rot-susceptible cultivars Rescue and S-615. A test of these cultivars against black point caused by Alternaria alternata found that all cultivars were as susceptible as the soft white spring wheat cultivar Fielder.Key words: Wheat, Cochliobolus sativus, black point, chromosome 5B

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