Pathogenic effects of Heterodera avenae and Rhizoctonia solani and their interaction on wheat

1971 ◽  
Vol 22 (2) ◽  
pp. 189 ◽  
Author(s):  
JW Meagher ◽  
SC Chambers

The effects of the cereal cyst nematode Heterodera arenae and the fungus Rhizoctonin solani on the growth of wheat seedlings were examined under glasshouse conditions. In combination, the pathogens caused significantly greater reduction in tillering, plant height, fresh weight, and root number and length than that caused by either pathogen when acting alone. Reduction in plant height, root number, and root length were the result of interaction. Nematode-fungus interaction may be the cause of disease in the field usually attributed to only one of these pathogens.

1978 ◽  
Vol 29 (6) ◽  
pp. 1127 ◽  
Author(s):  
JW Meagher ◽  
RH Brown ◽  
AD Rovira

Field trials in a sandy mallee soil in Victoria have shown that large increases (up to 323%) in grain yield are obtained by soil fumigation or the application of nematicides. Development of the plants was enhanced by control of soil-borne root pathogens. The occurrence of both cereal cyst nematode (H. avenae) and Rhizoctonia solani in patches of poor wheat in a field trial in South Australia indicate a possible association between these two pathogens. Glasshouse studies showed that the effects of H. avenae and R. solani on wheat were greater when both pathogens were together than with each individually.


1985 ◽  
Vol 25 (1) ◽  
pp. 191 ◽  
Author(s):  
A Simon ◽  
AD Rovira

In a field experiment, the numbers of immature females of cereal cyst nematode (Heterodera avenae Woll.) on roots of wheat at anthesis were 14 1, 220 and 324 per plant with 0, 100 and 400 kg/ha superphosphate respectively. The field site, with an average annual rainfall of 450 mm, was located at Coonalpyn, S.A. (35�4 1'S., 139� 52'E.) on a grey-brown, calcareous, loamy earth. Wheat seedlings were grown under controlled environment conditions in two soils with identical chemical and physical properties, but with initial populations of H. avenae of 1.1 and 5.8 eggs/g soil to study the response in shoot and root growth to superphosphate either mixed through the soil or banded with the seed. Using aldicarb, it was shown that H. avenae reduced the length of seminal root axes per plant by 33% in soil containing 1.1 eggs of H. avenae/g and by 74% in soil containing 5.8 eggs/g. Length of seminal root axes was not affected by superphosphate. The length of lateral roots per plant was increased by controlling H. avenae with aldicarb in soil containing 5.8 eggs/g but not in soil containing 1.1 eggs/g. When superphosphate was banded with the seed, the length of lateral roots per plant increased by 33% in soil containing 1.1 eggs/g and by 55% in soil containing 5.8 eggs/g. In soil containing the lower initial population of H. avenae, shoot dry weight was increased by 97% when superphosphate was mixed through the soil and 100% when banded with the seed. However, in soil containing the higher initial population of H. avenae, the responses were 48 and 94% to mixed and banded superphosphate respectively, indicating that plants severely infected with H. avenae are less able to utilize phosphate distributed through the soil. The results have practical implications in that the method of application and amount of superphosphate in fields infested with H. avenae will affect the build-up of the nematode when cereals are grown; furthermore, in infested soils, the plant response to superphosphate would be greater when the fertilizer is banded with the seed.


1981 ◽  
Vol 21 (112) ◽  
pp. 516 ◽  
Author(s):  
AD Rovira ◽  
PG Brisbane ◽  
A Simon ◽  
DG Whitehead ◽  
RL Correll

Significant yield responses of up to 0.9 t/ha were obtained with the nematicides aldicarb and dibromochloropropane in seven of eleven field trials with the wheat variety, Condor. Both nematicides reduced the numbers of white cysts of Heterodera avenae on the roots of wheat. With aldicarb the increase in wheat yields varied directly as the decrease in white cysts: dibromochloropropane gave similar increases in yield as aldicarb with a greater reduction in cyst numbers. There was no yield increase with either nematicide when cereal cyst nematode was not present. An analysis of covariance indicated that over all the sites 64% of the increase in yield due to aldicarb could be explained in terms of cysts of cereal cyst nematode.


Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 376-386 ◽  
Author(s):  
Richard W. Smiley ◽  
Guiping Yan

The cereal cyst nematode Heterodera avenae suppresses wheat production in the western United States. A second species of cereal cyst nematode, H. filipjevi, was identified in eastern Oregon during 2008. This paper reports the discovery of H. filipjevi–infested fields in eastern Washington, thereby extending the known distribution of H. filipjevi in the United States. The identity of H. filipjevi was determined and confirmed by species-specific polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism (RFLP), sequencing, and cyst morphology. Soils that were collected from naturally infested fields in Washington were used to compare the virulence of H. avenae and H. filipjevi on six spring wheat cultivars under controlled-environment conditions. Noninfested soils from nearby fields were used as controls. Cultivars Ouyen and WB Rockland were resistant to H. avenae and susceptible to H. filipjevi. Cultivars Sönmez and SY Steelhead were resistant to H. filipjevi and susceptible to H. avenae. Cultivars Louise and WB 936 were susceptible to both species. The resistance of SY Steelhead to ‘H. avenae’, reported in a previous paper, is corrected as resistance to H. filipjevi due to an earlier misidentification of H. filipjevi. Management guidelines that include crop rotations and resistant cultivars are presented. Discovery of additional infestations of H. filipjevi are anticipated when DNA-based tests become used routinely in commercial diagnostic laboratories.


Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 539-552 ◽  
Author(s):  
Richard W. Smiley ◽  
Guiping Yan ◽  
John N. Pinkerton

Abstract The cereal cyst nematode, Heterodera avenae, occurs in at least seven western states of the USA and reduces grain yield in localised regions and in selected crop management systems. Virulence phenotypes for H. avenae populations in North America have not been reported. Nine individual assays in six experiments were conducted to determine the reactions of barley, oat and wheat cultivars to five H. avenae populations in the Pacific Northwest (PNW) states of Idaho, Oregon and Washington. Three populations were evaluated for virulence to 23 entries of the 'International Test Assortment for Defining Cereal Cyst Nematode Pathotypes', plus selected local cultivars and entries representing a greater diversity of resistance genes. The virulence phenotype(s) for populations of H. avenae in the PNW did not correspond to any of the 11 pathotypes defined by the Test Assortment. Five PNW populations exhibited affinities with Group 2 but were not defined by pathotypes Ha12 and Ha22. Reproduction was prevented or greatly inhibited by barley carrying the Rha3 resistance gene and by most carriers of Rha2 resistance, and by selected oat cultivars with multigenic resistance. Wheat cultivars carrying the Cre1 resistance gene were highly effective in suppressing H. avenae reproduction. Current PNW wheat cultivars do not carry the Cre1 resistance gene. Crosses between Ouyen, an Australian bread wheat with Cre1 resistance, and several PNW wheat cultivars were resistant. The CreR gene also prevented H. avenae reproduction in the trial where it was tested. Intermediate levels of reproduction occurred on wheat cultivars carrying the Cre5, Cre7 and Cre8 resistance genes, each of which was considered useful for pyramiding into cultivars with Cre1 resistance. This research identified genetic resources of value in PNW cereal crop breeding programmes.


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