The relationship between incidence of infection by the take-all fungus (Gaeumannomyces graminis var. tritici), rainfall and yield of wheat in South Australia

1991 ◽  
Vol 31 (4) ◽  
pp. 509 ◽  
Author(s):  
DK Roget ◽  
AD Rovira

. This paper describes results obtained from an 8-year field trial on a calcareous sandy loam in South Australia. Different crop rotations resulted in varying percentages of plants with take-all [caused by Gaeumannomyces graminis var. tritici (Ggt)]. The results demonstrated that in a wheat-grass/medic pasture rotation, take-all caused an average annual yield loss in wheat of 29%. These yield losses were strongly correlated with disease incidence and rainfall in September (r2 = 0.91, P = 0.07) but only moderately correlated to disease incidence alone (r2 = 0.44, P = 0.09). The level of early infection (at 10 weeks) by Ggt was influenced by spring rainfall in the previous season. A regression model was developed to predict the incidence of take-all in a wheat crop from the incidence of take-all and the August-September rainfall the previous season (r2 = 0.96, P = 0.007) for a wheat-grass/medic pasture rotation (successive host plants).

1987 ◽  
Vol 38 (6) ◽  
pp. 1011 ◽  
Author(s):  
GC MacNish ◽  
DA Nicholas

The relationship between grass production in subterranean clover pastures with two different rotation histories and take-all in a subsequent wheat crop following barley was studied. Grass production in the pastures ranged from 0 to 1700 kg ha-1. The incidence of take-all in the wheat crop ranged from 10 to l00%, while the take-all severity percentage ranged from 4 to 99.In one rotation series (pasture 9 years; barley, barley, pasture, wheat), each kilogram increase in grass production in the last pasture year caused a 0.087% increase in the take-all severity rating. In the second series (pasture 7 years; oats, pasture 3 years; barley, wheat), each kilogram increase in grass production caused a 0.040% increase in severity. These figures are significantly different (P < 0.05). Thus the field history ranging back at least four seasons influenced the effects that grass level in the last pasture year had on take-all severity. Reductions in wheat yields ranged from 8.6 to 10.5 kg ha-1 for each 1% increase in take-all severity rating.


1973 ◽  
Vol 26 (6) ◽  
pp. 1277 ◽  
Author(s):  
GC Mac Nish

A bioassay was employed to compare the effect of various treatments on the level of G. graminis var. tritici inoculum in soil cores taken from a take-all patch. In a comparison of undisturbed soil and mixed soil, mixing caused a small reduction in incidence, possibly due to a dilution of the inoculum in the surface soil. Graded degrees of sieving from 5 to O� 5 mm mesh size caused a significant reduction in inoculum levels, with the latter reducing incidence to 3 % in seedlings at 4 weeks. However, it was also shown that increasingly finer sieving caused an increase in disease incidence if the seedlings were allowed to grow to maturity. It was not established whether the sieving affected the soil in such a way as to favour the pathogen, lower the resistance of the plant, or both.


1973 ◽  
Vol 26 (6) ◽  
pp. 1319 ◽  
Author(s):  
GC Mac Nish

A bioassay was used to study the effect of various storage treatments on the survival of G. graminis var. tritici in soil cores removed from a take-all patch. There was no significant change in the incidence of the fungus when the soil was maintained either dry (-250 to -980 bars) and cool (15�C), or moist (-4'0 to -7,0 bars) and cool (15�C). When maintained very dry (-980 bars or less) and hot (35�C) or wet (-0'1 to -0,2 bar) and cool (15�C) there was a significant reduction in disease incidence, but considerable levels of viable fungus were still present after 45 weeks storage. Only in wet hot soil (-0'1 to -0,2 bar and 35�C) was the fungus eliminated rapidly.


Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 443-451 ◽  
Author(s):  
Sean L. Bithell ◽  
Alan McKay ◽  
Ruth C. Butler ◽  
Herdina ◽  
Kathy Ophel-Keller ◽  
...  

The lack of accurate detection of Gaeumannomyces graminis var. tritici inoculum in soil has hampered efforts to predict the risk of severe take-all for wheat growers. The current study used a molecular method to quantify soil G. graminis var. tritici concentrations in commercial wheat fields in New Zealand and to compare them with the proportion of crops surpassing the thresholds for visible and moderate to severe take-all over three growing seasons. The study evaluated a soil G. graminis var. tritici DNA-based take-all prediction system developed in Australia, with four take-all risk categories. These categories were found to be useful for predicting disease severity in second wheat but did not clearly separate risk between fields in medium- and high-risk categories. A sigmoidal relationship was identified between inoculum concentration and the proportion of fields exceeding the two disease thresholds. A logistic response curve was used to further examine this relationship and evaluate the boundaries between take-all risk categories. G. graminis var. tritici boundaries between medium- and high-risk categories were clustered near or within the upper plateau of the relationship. Alternative G. graminis var. tritici boundaries for a three-category system were identified that provided better separation of take-all risk between categories. This information could improve prediction of the risk of severe take-all.


1979 ◽  
Vol 93 (2) ◽  
pp. 377-389 ◽  
Author(s):  
D. B. Slope ◽  
R. D. Prew ◽  
R. J. Gutteridge ◽  
Judith Etheridge

SUMMARYThe Rothamsted ley–arable experiments were on two fields with similar soils but with contrasting previous cropping: old grass on Highfield, old arable on Fosters field. Damage by take-all (Qaeumannomyces graminis var. tritici) occurred sooner in successive wheat crops grown after a lucerne ley and arable sequence (LU) than after a grass-clover ley and arable sequence (LC). On Highfield the difference was consistent and large, it occurred as soon as a second wheat crop was grown and resulted in wheat yielding 1 t/ha less after the LU than after the LC sequence. This difference did not persist in the next wheat crop where take-all was prevalent after both sequences. On Fosters field take-all developed more slowly and differences between sequences were mostly smaller.Wheat seedling bio-assay of soil cores from the LU and LC sequences showed that little take-all fungus persisted through the leys and that soils were much infested after a first wheat crop in the LU sequence on Highfield, but not in the LC sequence on Highfield or in either sequence on Fosters field. Microscopic examination of roots from assay seedlings and from field plants showed that Phialophora radicicola var. graminicola (PRG) was most common in soils where take-all developed slowly, but our results did not show if this was a causal relationship. The occurrence of much PRG in the LU sequence on Fosters conflicts with previous reports which associate large populations of this fungus only with grassland soils.


1973 ◽  
Vol 26 (6) ◽  
pp. 1301 ◽  
Author(s):  
GC Mac Nish ◽  
RL Dodman

A mapping technique based on an "incidence-yield" regression was used to study the incidence of G. graminis var. tritici in consecutive wheat crops at two locations in South Australia. At both locations there were only small differences between the two years, although at Turretfield (third and fourth crops) there was a tendency for highincidence areas to contract, while at Ceduna (second and third crops) disease incidence tended to increase.


1987 ◽  
Vol 27 (3) ◽  
pp. 419 ◽  
Author(s):  
JF Kollmorgen ◽  
PE Ridge ◽  
RFde Boer

In 4 trials in the Northern Wimmera of Victoria, the incidence and severity of take-all of wheat caused by Gaeumannomyces graminis var. tritici were generally unaffected by tillage treatments (nil, chemical weed control; subsurface, blade plough and rod weeder; conventional scarifier, cultivator and harrows). At 1 site at 1 sampling time disease incidence was higher after conventional tillage than after subsurface tillage and at another site in 1 year out of 3, disease severity was greater after nil tillage than after conventional tillage. A stubble mulch of 4 t ha-1 of straw and burial at 5 or 10 cm reduced survival of the take-all fungus in wheat crowns.


Plant Disease ◽  
2006 ◽  
Vol 90 (9) ◽  
pp. 1161-1166 ◽  
Author(s):  
Barry M. Cunfer ◽  
G. David Buntin ◽  
Daniel V. Phillips

Take-all of wheat (Triticum aestivum), caused by Gaeumannomyces graminis var. tritici, became a serious problem with the widespread adoption of wheat:soybean double-cropping and minimum tillage farming systems in the southeastern United States during the past 30 years. A long-term crop rotation study was initiated in 1994 with 12 double-cropping sequences incorporating wheat, rye, or canola as the fall-planted crop and soybean or grain pearl millet as the summer crop. Cotton and fallow were included in some summer rotations during the last 2 years of the study. The purpose was to identify sustainable alternatives to the continuous wheat:soybean system that would provide acceptable management of take-all. G. graminis var. tritici cultured on autoclaved oats was incorporated into soil prior to planting the first season's crop. Take-all was severe in rotations with continuous wheat each year. Pearl millet was compatible with the cropping system but did not affect incidence or severity of take-all in a following wheat crop. Soybean or pearl millet had little effect on yield loss due to take-all in a subsequent wheat crop. A 1-year rotation with canola significantly reduced take-all incidence and severity. At the end of the second and third seasons, in those rotations where wheat followed 1 year of canola, wheat grain yield was the same as that in control plots that had little or no take-all. Two consecutive years of canola did not suppress take-all or improve wheat yields any more than a single year of canola between wheat crops. Seedling assays for take-all incidence and severity in growth chambers were conducted using soil collected twice each year near the end of each crop's growing season. Results were similar to those observed in the field. However, canola in the rotation had a greater effect in suppressing disease severity than disease incidence. Canola can be a valuable rotational crop for management of take-all in wheat in the southeastern United States.


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