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

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.

1974 ◽  
Vol 52 (7) ◽  
pp. 1757-1764 ◽  
Author(s):  
P. R. Verma ◽  
R. A. A. Morrall ◽  
R. D. Tinline

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.


1992 ◽  
Vol 43 (1) ◽  
pp. 43 ◽  
Author(s):  
GB Wildermuth ◽  
RD Tinline ◽  
RB McNamara

The effects of common root rot (CRR) caused by Bipolaris sorokiniana on grain yield, number of tillers, number of grains and grain weight of wheat plants were determined in four field experiments. Sites with different soil populations of B. sorokiniana were selected and inoculum of the fungus added to some plots. Disease and yield measurements were made on eight cultivars and lines differing in susceptibility to CRR. Timgalen, Songlen and Hartog were susceptible whereas Kite, 1008 C16, 141-4 and ISWYN 32 were partially resistant to CRR. Grain yield, tiller and grain number, but not grain weight decreased as disease severity increased. Diseased plants had lower tiller numbers than healthy ones and as a consequence a reduced number of grains and grain yield per plant. Five methods were compared for estimating yield loss caused by the disease. Polynomial regression equations for each cultivar between yield and disease rating of sub-crown internodes or multiple regression equations between yield and disease parameters of sub-crown internodes or tiller bases were established. A third method involved the projection of yield losses from one cultivar to other cultivars and in a fourth method yield losses were estimated from actual yields. In addition, an equation Yield loss (%) = 3 46 + 0.23 disease severity) (%) was established in one experiment and used as a fifth method in the other experiments. Yield losses estimated by methods 1 and 2 were similar and higher than those from the other methods. In areas where disease severity is high, methods 1 and 5 appear to be the most suitable for determining yield losses. Losses in a susceptible cultivar, Timgalen, varied between 13.9 and 23.9% whereas those in a partially resistant cultivar, 1008 C16, varied between 6.8 and 13.6%.


2019 ◽  
Vol 12 (2) ◽  
pp. 91-96
Author(s):  
M.I.E. Arabi ◽  
E. Al-Shehadah ◽  
M. Jawhar

Abstract The yield response of widely grown cultivars and landraces of Syrian wheat challenged with common root rot (CRR: Cochliobolus sativus) was measured by comparing plots with and without artificial inoculation under experimental conditions in two consecutive seasons. The results showed that response to CRR differed depending on the susceptibility levels of the wheat cultivars, and that the disease significantly (P<0.05) reduced grain yield, number of tillers and kernel weight. The diseased plants had fewer tillers which consequently reduced grain yield per plant. Yield losses of Triticum durum cultivars were higher than those of Triticum aestivum. In addition, the T. durum landrace Horani exhibited the best level of resistance to the disease, which indicates that this landrace might be a candidate donor for resistance in future breeding programmes. As CRR can dramatically reduce wheat grain yields under favorable conditions, management practices that reduce disease severity are highly recommended.


1975 ◽  
Vol 53 (12) ◽  
pp. 1230-1238 ◽  
Author(s):  
P. R. Verma ◽  
R. D. Tinline ◽  
R. A. A. Morrall

The effects of various treatments such as herbicide, irrigation, nitrogen, phosphate, and combinations of nitrogen and phosphate on common root rot (Cochliobolus sativus) in naturally infected Triticum aestivum cultivar ‘Manitou’ were studied at Matador, Saskatchewan, by sampling plants at intervals during 1969, 1970, and 1971. The treatments were compared for each of the following variables : number of diseased plants per square metre, percentages of diseased plants, and percentage disease ratings. Usually, disease assessed by each variable was higher in the checks than in the phosphate treatments. The effect of phosphate appeared maximal at midseason (growth stage 9–10.5). The differences between treatments such as herbicide, nitrogen, and irrigation and the checks were insignificant. A comparison with the results of other workers suggests interaction between phosphate and soil type, and between phosphate and cultivar.


1993 ◽  
Vol 73 (4) ◽  
pp. 1177-1187 ◽  
Author(s):  
L. J. Duczek ◽  
G. B. Wildermuth

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


1996 ◽  
Vol 76 (4) ◽  
pp. 869-877 ◽  
Author(s):  
R. L. Conner ◽  
G. C. Kozub ◽  
K. L. Bailey

The impact of common root rot, caused by Cochliobolus sativus, on the yield of mixtures of resistant and susceptible backcross-6 derivative lines of Neepawa and Chester wheat was examined in field tests at three locations between 1991 and 1994. Different blends consisting of all 25% incremental combinations of resistant and susceptible back-cross lines within each cultivar were evaluated for disease severity and yield at root rot nurseries and disease-free sites. Significant (P < 0.05) differences in yield were often detected among cultivars. However, within cultivars, no consistent yield differences were observed among blends of resistant and susceptible lines of the same cultivar regardless of root rot severity. Key words:Cochliobolus sativus, common root rot, yield, wheat


1968 ◽  
Vol 48 (5) ◽  
pp. 479-486 ◽  
Author(s):  
Hugh McKenzie ◽  
T. G. Atkinson

Inheritance of reaction to common root rot, caused chiefly by Cochliobolus sativus, was studied in F3 populations of wheat, Triticum aestivum, from crosses between the root-rot-resistant, hollow-stemmed varieties, Thatcher and Pembina, and the moderately root-rot-susceptible, solid-stemmed variety, CT 733. The results indicated that the resistance of Thatcher and Pembina, which appear to have the same gene complement, is controlled by a major recessive gene and one or two minor genes.No association was found between inheritance of root-rot reaction and the inheritance of stem solidness which determines resistance to the wheat stem sawfly (Cephus cinctus). Therefore, there should be no difficulty in incorporating root-rot resistance into sawfly-resistant varieties.


1977 ◽  
Vol 55 (1) ◽  
pp. 30-34 ◽  
Author(s):  
R. D. Tinline

In the greenhouse, subcrown internodes of wheat plants were inoculated with Cochliobolus sativus (Ito & Kurib.) Drechsler ex Dastur, Fusarium culmorum (W. G. Smith) Sacc., F. acuminatum Ell. & Ev., or F. sulplureum Schlecht. and at various times subsequently with C. sativus; or the internodes were inoculated with C. sativus and subsequently with it or a Fusarium sp. Using isolation of the fungi as the criterion for infection, it was found that prepossession of the internode by C. sativus did not prevent later invasion by it or by the fusaria; however, C. sativus was a relatively unsuccessful challenger to F. culmorum and F. acuminatum. The results suggest that when C. sativus and one of these two Fusarium spp. appear together in isolations from common root rot diseased plants that the initial invader was C. sativus.


1984 ◽  
Vol 64 (2) ◽  
pp. 245-253 ◽  
Author(s):  
W. E. GREY ◽  
D. E. MATHRE

The effects of common root rot (CRR), caused primarily by Cochliobolus sativus, on yield components in 16 barley cultivars representative of three groups—two-row (Hannchen and Smyrna types), Coast, and Manchuria—were studied at Bozeman and Glasgow, Mont, in 1980. At Bozeman, autoclaved oat kernels colonized by Cochliobolus sativus added with seed, effected a mean disease rating (DR) among the cultivars of 42.8, compared to 30.3, when autoclaved uncolonized oat kernels were added. In spite of the mean increase in disease severity of the inoculated plots, there was no significant difference in yield between inoculated and noninoculated plots. Later developed yield components, i.e. kernels per spike and kernel weight, compensated for the initial reduction in fertile tillers caused by CRR. Therefore, in population of plants under disease pressure from CRR, compensating effects on yield components may allow for little or no overall yield reduction, particularly in cultivars that are not highly susceptible to CRR. The two-row, Hannchen-type cultivars were all intermediate in DR at both locations. The two-row, Smyrna-type cultivars were high in susceptibility at Glasgow but intermediate in reaction to CRR at Bozeman. The six-row, Manchuria-Coast groups of cultivars were more diverse in their reaction to CRR at both locations. It appears that genetic relationships have more influence on a cultivar’s disease rating to CRR than has grouping based upon physiological characteristics.Key words: Barley groups, Cochliobolus sativus, yield components


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