Failure of liming to increase grain yield of wheat and triticale in acid soils may be due to the associated increase in incidence of take-all (Gaeumannomyces graminis var. tritici)

1987 ◽  
Vol 27 (3) ◽  
pp. 411 ◽  
Author(s):  
GM Murray ◽  
BJ Scott ◽  
Z Hochman ◽  
BJ Butler

Lime was applied at rates from 0 to 5.0 t ha-1 at 4 sites in southern and central New South Wales. A root and crown disease characterised by basal stem blackening affected up to 60% of wheat plants and 80% of triticale plants when the soil pH in 0.01 mol L-1 CaCl2 was above 5.0 at all 4 sites. Below pH 4.8, incidence was less than 5%. The take-all fungus, Gaeumannomyces graminis var. tritici, was consistently associated with this symptom. Losses in grain yield from the disease ranged from 26 to 77% depending on site. Regression analysis indicates that each 10% increase in plants with basal stem blackening decreased yield by 0.76%. These results demonstrate that the disease can reverse the expected increase in yield after liming, and that progressive acidification of the soils in the region may have caused the present reduced amount of take-all.

2002 ◽  
Vol 42 (8) ◽  
pp. 1087 ◽  
Author(s):  
C. R. Kidd ◽  
G. M. Murray ◽  
J. E. Pratley ◽  
A. R. Leys

Winter cleaning is the removal of grasses from pasture using selective herbicides applied during winter. We compared the effectiveness of an early (June) and late (July) winter cleaning with an early spring herbicide fallow (September), spring (October) herbicide and no disturbance of the pasture on development of the root disease take-all in the subsequent wheat crop. Experiments were done at 5 sites in the eastern Riverina of New South Wales in 1990 and 1991. The winter clean treatments reduced soil inoculum of Gaeumannomyces graminis var. tritici (Ggt) compared with the other treatments at all sites as measured by a bioassay, with reductions from the undisturbed treatments of 52–79% over 5 sites. The winter clean treatments also significantly reduced the amount of take-all that developed in the subsequent wheat crop by between 52 and 83%. The early and late winter clean treatments increased the number of heads/m2 at 3 and 1 sites, respectively. Dry matter at anthesis was increased by the winter clean treatments at 3 sites. Grain yield was increased by the winter cleaning treatments over the other treatments at the 4 sites harvested, with yield increases of the early winter clean over the undisturbed treatment from 13 to 56%. The autumn bioassay of Ggt was positively correlated with spring take-all and negatively correlated with grain yield of the subsequent wheat crop at each site. However, there was a significant site and site × bioassay interaction so that the autumn bioassay could not be used to predict the amount of take-all that would develop.


2005 ◽  
Vol 45 (4) ◽  
pp. 435 ◽  
Author(s):  
J. L. Cooper

Two forms of biosolids, with and without lime, were applied to acid soils at 2 sites in central New South Wales. Wheat and triticale were then grown on these sites to determine the effect of biosolids on crop growth and yield. The forms of biosolids used were dewatered sewage sludge cake, and N-Viro Soil which is a lime amended sewage sludge. Dewatered sewage sludge cake was applied at rates of 0, 6, 12 and 24 dry Mg/ha, and N-Viro soil at 0, 1.5, 3.0 and 4.5 dry Mg/ha. Biosolids produced grain yield increases of over 50% at both sites, with the largest yield increases at the highest rate of dewatered sewage sludge. Continued cropping at 1 of the sites showed that significant yield increases were still obtained 3 years after the initial application. The addition of lime and N-Viro Soil raised soil pH, and produced small but long lasting yield increases. However, the main benefit of biosolids seems to have come from the nutrients they supplied rather than changes in soil pH.


1985 ◽  
Vol 25 (1) ◽  
pp. 149 ◽  
Author(s):  
LJ Horsnell

The response of improved pastures to the application of superphosphate is low on the acid sedimentary soils, of the Southern Tablelands of New South Wales, which contain high levels of exchangeable aluminium. An investigation was made into the effect of surface-applied fertilizers on soil pH and on the establishment and growth of lucerne and phalaris on these soils. At 6 weeks after the application of gypsum, superphosphate, or superphosphate plus potassium sulfate, soil pH (H2O) had decreased markedly. This effect extended to a depth of 20 cm, but decreased with time. Initially, lime application increased the pH of the surface soil only. When superphosphate was applied with lime the pH of the soil under the lime layer decreased to the same level as that found in the soil treated with superphosphate alone. Lime, however, had penetrated into the subsoil 102 weeks after application and substantially more so after 13 years. Soil pH (0.01 M CaCl2) was not depressed by the application of fertilizers. Growth and persistence of both species in the first summer were poor, but growth responses to phosphorus, lime and nitrogen increased after the first year. Lucerne showed large growth responses to lime, greater than those found on plots receiving nitrogen fertilizer. Lime reduced aluminium levels both in lucerne plants and in soil. It is suggested that the slow penetration of lime into the soil, the relatively quick effect of superphosphate in increasing subsoil acidity, and high soil aluminium levels are together responsible for the poor persistence and slow growth of both lucerne and phalaris in the early stages. The subsequent large dry matter responses of lucerne to lime are possibly related to increased nitrogen fixation and a lowering of plant and soil aluminium levels. It is suggested that the lime responses of phalaris are also related to lower aluminium levels.


1988 ◽  
Vol 39 (1) ◽  
pp. 1 ◽  
Author(s):  
NS Wilhelm ◽  
RD Graham ◽  
AD Rovira

Two experiments tested the effectiveness of manganese (Mn) decreasing take-all of wheat. The first experiment was conducted under controlled environmental conditions. Mn sulfate was mixed through the soil at sowing or 2 weeks before, or applied to the seed or leaves, and manganese dioxide (MnO2) was mixed through the soil at sowing or 2 weeks before. Mixing manganese sulfate (MnSO4) through the soil was the most effective treatment at decreasing take-all, followed by seed applied Mn. MnO2 and foliar applied Mn had little effect on take-all. All Mn treatments, except foliar Mn, completely eliminated Mn deficiency in the plants. In the second experiment, which was conducted in the field at a Mn deficient site, Mn sulfate and MnO2 were applied to the soil at sowing. MnSO4 decreased take-all and increased grain yields in take-all inoculated plots nearly threefold, but increased yields only slightly in uninoculated plots. MnO2 was not effective in decreasing take-all or increasing grain yield. This is the first report of take-all infection being suppressed by MnSO4in the field. The results of these experiments support the hypothesis that Mn may be acting through the physiology of the wheat plant to decrease take-all.


1991 ◽  
Vol 31 (2) ◽  
pp. 211 ◽  
Author(s):  
J Brockwell ◽  
A Pilka ◽  
RA Holliday

Measurements were made of soil pH, frequency of occurrence of annual species of Medicago (medics) and populations of Rhizobium meliloti at 84 sites on 7 dominant soil groups of the Macquarie region of central-western New South Wales. Over all sites, soil pH (0-10 cm; 1:5 soil: water) ranged from 5.26 to 8.07, medic frequency from 0 to 100% and most probable numbers of R. meliloti from undetectable to 675 000/g soil. There was a highly significant (P<0.001) relationship between soil pH and number of R. meliloti. Above pH 7.0, the mean soil population of R. meliloti was 89000/g; below pH 6.0, it was 37/g. Medics occurred most frequently on the more alkaline soils and with least frequency on the more acid soils, but the relationship between soil pH and medic frequency was weaker than between pH and R. meliloti number. Medics were more tolerant of low soil pH than their rhizobia were; at 2 sites, of pH 5.49 and 5.35, medics occurred at 100% frequency but R. meliloti was undetected. There was an indication of some acidification in these soils over a period of 35 years but this remains to be confirmed.


Soil Research ◽  
1991 ◽  
Vol 29 (5) ◽  
pp. 627 ◽  
Author(s):  
OF Glenn ◽  
K Sivasithamparam

Experiments were conducted firstly, to determine whether there was a difference in saprophytic growth response of the pathogen to pH in soil from that on agar. Secondly, we examined whether the response to liming involved a sensitivity of the fungus to the concentration of hydrogen (H+) or calcium ions (Ca2+). The saprophytic growth of the take-all fungus showed that, although it is sensitive to soil pH, each strain behaves differently, and this behaviour cannot be predicted from agar studies. It seems unlikely, therefore, that the observed disease response to soil pH resulted from direct effects on the saprophytic phase of the fungus. There was no indication that increase in the Ca2+ in soil played any part in the growth response of the fungus. The potential for other indirect effects of pH on nutrient availability to the plant and to other stages in the disease cycle is discussed.


1988 ◽  
Vol 28 (3) ◽  
pp. 333 ◽  
Author(s):  
GC MacNish

Experiments were conducted to test the hypotheses that: (i) continuous cropping with wheat would lead to a decline in take-all, (ii) ammonium nitrogen would reduce take-all compared with nitrate nitrogen, and (iii) that both sources of nitrogen would lead to a decline in soil pH. Attempts were also made to confirm that rhizoctonia root rot would vary unpredictably in continuous wheat and would be reduced by nitrogen. Wheat was grown without nitrogen (Nil) or with sodium nitrate (SN) or ammonium sulfate (AS) for 11, 10 and 9 consecutive years at Newdegate, Esperance and Mount Barker respectively. Rates of nitrogen were 50, 25 and 45 kg ha-1 at Newdegate, Esperance and Mount Barker respectively. A decline in take-all incidence was established at Newdegate, and plots treated with AS generally had a lower take-all incidence than did plots without nitrogen or treated with SN. At Esperance, a decline in take-all incidence was established only in AS treated plots. Take-all incidence was lower in plots treated with AS than plots without nitrogen or treated with SN in 6 years out of 10 at Esperance. No take-all decline was observed at Mount Barker and take-all incidence was rarely lower in plots treated with AS than in those without nitrogen or treated with SN. All treatments reduced soil pH at Newdegate and Esperance, which were weakly buffered sites, but at Mount Barker (a highly buffered site) only AS reduced pH. Rhizoctonia root rot was not found at Mount Barker. At Newdegate and Esperance it first occurred in the eighth and fifth crops respectively. Incidence peaked at about 60% of plants being affected in the ninth crop at Newdegate and 95% in year 7 at Esperance, and then declined to less than 5% at both sites. Applications of nitrogen had no effect on incidence of rhizoctonia root rot. Yields varied considerably between sites and years. Combining results for all years at each site showed that AS increased yield at all sites and SN increased yields at Newdegate and Mount Barker compared with no nitrogen. The continued use of AS at Mount Barker eventually had an adverse effect on yield.


1986 ◽  
Vol 37 (1) ◽  
pp. 11 ◽  
Author(s):  
RM Sward ◽  
JF Kollmorgen

The single and combined effects of barley yellow dwarf virus (BYDV) and the take-all fungus, Gaeumannomyces graminis var. tritici (Ggt) on wheat, cv. Condor, were determined in field and glasshouse trials. Before and after tillering, aphids with BYDV were fed on plants growing in soil with different proportions of dead and live inoculum of Ggt. Each pathogen reduced grain yield and increased the number of deadheads. In a number of cases, especially in the field, the combined effect of BYDV and Ggt was greater than a simple additive effect of either pathogen alone. Grain yield per plot and grain weight per head were each reduced, whilst the incidence of deadheads was increased, particularly following infection with BYDV after tillering. A possible mechanism to explain the interaction of the two pathogens is discussed.


1989 ◽  
Vol 29 (2) ◽  
pp. 247 ◽  
Author(s):  
RF Brennan

Wheat was grown in soil amended with 5 levels of superphosphate with or without 4 levels of flutriafol at 3 sites naturally infested with Gaeumannomyces graminis var. tritici. The severity of take-all was related to the rates of superphosphate and flutriafol. At all sites, the disease incidence and severity were high, with values for the moderate plus severe category (i.e. >25% of the root system discoloured by the takeall fungus) exceeding 80% for untreated plots. As plants responded to increasing levels of superphosphate and flutriafol, the percentage of infected roots declined. There was no further decline in the severity of take-all with increasing levels of flutriafol above 50 g/ha. The lowest severity of take-all was observed at the highest superphosphate level (200 kg/ha) and a fungicide level of 50 g/ha. Take-all severity for this treatment varied with the site location, being 52% at Condingup while the Mt Ridley and Neridup sites had 60% infection of take-all on the roots. There was a 25-30% increase in grain yield in response to added flutriafol at the highest superphosphate level. There were also corresponding increases in dry matter production and 1000-grain weights with superphosphate and fungicide application.


2010 ◽  
Vol 100 (5) ◽  
pp. 404-414 ◽  
Author(s):  
Youn-Sig Kwak ◽  
Peter A. H. M. Bakker ◽  
Debora C. M. Glandorf ◽  
Jennifer T. Rice ◽  
Timothy C. Paulitz ◽  
...  

Dark pigmented fungi of the Gaeumannomyces–Phialophora complex were isolated from the roots of wheat grown in fields in eastern Washington State. These fungi were identified as Phialophora spp. on the basis of morphological and genetic characteristics. The isolates produced lobed hyphopodia on wheat coleoptiles, phialides, and hyaline phialospores. Sequence comparison of internal transcribed spacer regions indicated that the Phialophora isolates were clearly separated from other Gaeumannomyces spp. Primers AV1 and AV3 amplified 1.3-kb portions of an avenacinase-like gene in the Phialophora isolates. Phylogenetic trees of the avenacinase-like gene in the Phialophora spp. also clearly separated them from other Gaeumannomyces spp. The Phialophora isolates were moderately virulent on wheat and barley and produced confined black lesions on the roots of wild oat and two oat cultivars. Among isolates tested for their sensitivity to 2,4-diacetylphloroglucinol (2,4-DAPG), the 90% effective dose values were 11.9 to 48.2 μg ml–1. A representative Phialophora isolate reduced the severity of take-all on wheat caused by two different isolates of Gaeumannomyces graminis var. tritici. To our knowledge, this study provides the first report of an avenacinase-like gene in Phialophora spp. and demonstrated that the fungus is significantly less sensitive to 2,4-DAPG than G. graminis var. tritici.


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