The relationship between the spore density of Cochliobolus sativus in soil and its saprophytic activity and parasitism

1968 ◽  
Vol 8 (32) ◽  
pp. 371 ◽  
Author(s):  
LW Burgess ◽  
DM Griffin
Keyword(s):  
Wheat Straw ◽  
Root Rot ◽  
Cochliobolus Sativus ◽  
Spore Density ◽  
Common Root ◽  
Common Root Rot ◽  
The Relationship ◽  
Seedling Infection

Both saprophytic colonization of wheat straw and seedling infection by Cochlioholus sativus (Ito and Kur.) Drechsl. ex Dastur, which causes common root rot of wheat, were correlated with spore density. The results indicate that straw colonization is possible at 10�C even when the spore density is too low to cause seedling infection. Saprophytic activity may thus raise the spore density over the threshold necessary for parasitism.

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

Assessment of tolerance in wheat and barley to common root rot (Cochliobolus sativus)

1993 ◽  
Vol 73 (4) ◽  
pp. 1177-1187 ◽  
Author(s):  
L. J. Duczek ◽  
G. B. Wildermuth
Keyword(s):  
Grain Yield ◽  
Root Rot ◽  
Dry Matter ◽  
Field Tests ◽  
Cochliobolus Sativus ◽  
Disease Assessment ◽  
Growth Stages ◽  
Common Root ◽  
Common Root Rot ◽  
The Relationship

Field tests at Saskatoon, Saskatchewan, Canada indicated no evidence of tolerance to common root rot in four spring wheat cultivars. There was a relationship between increased yield losses and increasing disease. In barley, the relationship was inconsistent in four cultivars and there was evidence of tolerance or recovery in Melvin with the number of seeds per head increasing with the level of disease. In Queensland, Australia there was evidence of tolerance in the wheat cultivar Banks across two locations, but the response was not consistent in all cultivars. Dry matter loss at immature growth stages was not related to grain yield loss. The inconsistent expression of tolerance in wheat, the difficulty of assessing it, and the difficulty of distinguishing tolerance from recovery suggest that the assessment of tolerance is not a reliable method of determining the reaction to common root rot. The relationship between loss in dry matter and grain yield, as disease increased, indicates that disease assessment should continue to be based on severity of symptoms. The evidence of tolerance to common root rot in barley suggests research on tolerance should concentrate on barley instead of wheat. Key words: Cochliobolus sativus, common root rot, tolerance, wheat, barley

The epidemiology of common root rot in Manitou wheat: disease progression during the growing season

1974 ◽  
Vol 52 (7) ◽  
pp. 1757-1764 ◽  
Author(s):  
P. R. Verma ◽  
R. A. A. Morrall ◽  
R. D. Tinline
Keyword(s):  
Triticum Aestivum ◽  
Disease Severity ◽  
Plant Development ◽  
Root Rot ◽  
Growing Season ◽  
Cochliobolus Sativus ◽  
Infection Rates ◽  
Common Root ◽  
Common Root Rot ◽  
Disease Rating

Common root rot in Triticum aestivum cultivar Manitou caused primarily by Cochliobolus sativus was followed during plant development in 1969, 1970, and 1971 at Matador, Saskatchewan. Plants were sampled at intervals, and three variables based mainly on the occurrence of lesions on subcrown internodes were studied: number of diseased plants per square meter; percentage of diseased plants; and disease rating which integrated percentage of diseased plants and disease severity on each plant. All variables increased with time, and the progression curves in all 3 years were hyperbolic, indicating that the increases were like those of a simple interest disease as described by Van der Plank. In two of the years, almost 100% of the plants were diseased considerably before the end of the season. The transformation proposed by Van der Plank for simple interest diseases, log10[1/(1 − x)], was applied to the percentages of diseased plants, and regressions were calculated. The slopes of these lines (infection rates) were as follows: 1969, 0.99% plants per day; 1970, 1.32%; and 1971, 1.96%. In 1969 the onset of disease was later than in 1970 and 1971, and there was correspondingly less disease at the end of the growing season.

The effect of common root rot on components of grain yield in Manitou wheat

1976 ◽  
Vol 54 (24) ◽  
pp. 2888-2892 ◽  
Author(s):  
P. R. Verma ◽  
R. A. A. Morrall ◽  
R. D. Tinline
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Disease Severity ◽  
Root Rot ◽  
Major Effect ◽  
Kernel Weight ◽  
The Other ◽  
Cochliobolus Sativus ◽  
Common Root ◽  
Common Root Rot

The effects of common root rot (Cochliobolus sativus) on components of grain yield in naturally infected Triticum aestivum cultivar Manitou were studied at Matador, Saskatchewan, by sampling plants at maturity in 1969, 1970, and 1971. Plants were sorted into severe (SE), moderate (MO), slight (SL), and clean (CL) categories based mainly on the extent of lesions on the subcrown internodes. The number of tillers per plant, the number and weight of grains per head, the weight per head, and the 1000-kernel weight in each category were determined. Increasing values of all five components were consistently associated with decreasing disease severity. SE was mostly significantly different from the other three categories in all components except 1000-kernel weight; differences between SL and MO were usually non-significant. CL and SL were mostly significantly different for the number of tillers per plant and weight per head but non-significant for the weight and number of grains per head and 1000-kernel weight. Apparently, the major effect of common root rot was to reduce the number of tillers per plant and number of grains per head.

Further sources of resistance to common root rot (Cochliobolus sativus) of wheat

1974 ◽  
Vol 14 (70) ◽  
pp. 666 ◽  
Author(s):  
GB Wildermuth
Keyword(s):  
Bread Wheat ◽  
Root Rot ◽  
First Record ◽  
Cochliobolus Sativus ◽  
Wheat Cultivars ◽  
Common Root ◽  
Sources Of Resistance ◽  
Common Root Rot ◽  
High Level

One cultivar of einkhorn, one cultivar of emmer, three cultivars of durum and 43 cultivars of bread wheat were screened for resistance to common root rot (Cochliobolus sativus). The emmer cultivar, Yaroslav and the white-grained bread wheat cultivars, Festival and Mexico 120, showed a high level of resistance. This is the first record of resistance in white-grained cultivars and the advantage of using whitegrained rather than red-grained cultivars as sources of resistance in Australia is indicated. It is considered that the major source of resistance in Festival, Gamut and Spica has been derived from Pusa cultivars.

The transfer and characterization of resistance to common root rot from Thinopyrum ponticum to wheat

Genome ◽  
2004 ◽  
Vol 47 (1) ◽  
pp. 215-223 ◽  
Author(s):  
Hongjie Li ◽  
Robert L Conner ◽  
Qin Chen ◽  
Haiyan Li ◽  
André Laroche ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Root Rot ◽  
Triticum Aestivum L ◽  
Genomic In Situ Hybridization ◽  
Cochliobolus Sativus ◽  
Common Root ◽  
Thinopyrum Ponticum ◽  
Common Root Rot ◽  
Kernel Color

Common root rot, caused by Cochliobolus sativus (Ito and Kurib) Drechs. ex Dastur, is a major soil-borne disease of spring and winter wheat (Triticum aestivum L. em Thell.) on the Canadian prairies. Resistance to common root rot from Thinopyrum ponticum (Podp.) Liu and Wang was transferred into wheat via crossing with Agrotana, a resistant wheat – Th. ponticum partial amphiploid line. Evaluation of common root rot reactions showed that selected advanced lines with blue kernel color derived from a wheat × Agrotana cross expressed more resistance than the susceptible T. aestivum 'Chinese Spring' parent and other susceptible wheat check cultivars. Cytological examination revealed 41 to 44 chromosomes in the advanced lines. Genomic in situ hybridization, using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. Löve (St genome) as a probe, demonstrated that the blue kernel plants had two pairs of spontaneously translocated J–Js and Js–J chromosomes derived from the J and Js genome of Th. ponticum. The presence of these translocated chromosomes was associated with increased resistance of wheat to common root rot. The lines with blue aleurone color always had a subcentromeric Js–J translocated chromosome. The subtelocentric J–Js translocated chromosome was not responsible for the blue kernel color. The genomic in situ hybridization analysis on meiosis revealed that the two spontaneous translocations were not reciprocal translocations.Key words: Cochliobolus sativus, genomic in situ hybridization, blue kernel color.

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