Detection of Gaeumannomyces Graminis Var. Tritici in Wheat Stubble

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Bioassays of wheat stubble were used to study the survival of G. graminis var. tritici in the field. There were marked differences in survival between the two localities investigated. At Ceduna the number of macro-sites with stubble (crowns) containing viable G. graminis var. tritici dropped from 90 % in early February to 82 % in midNovember, while at Turretfield the drop was from 96 % in late January to 30 % in late August. In another experiment at Ceduna, the survival of G. graminis var. tritici in field soil was studied using a bioassay of soil cores. There was only a small drop in the incidence of G. graminis var. tritid in cores removed at regular intervals from the takeall patch over a period of nearly one year.

Section: (A) Cedunamentioning

confidence: 99%

“…Both the bioassay of stubble (Mac Nish 1973) and the bioassay of soil cores ) were employed in assessing the level of viable fungus in the field.…”

Section: Introductionmentioning

confidence: 99%

Survival of Gaeumannomyces Graminis Var. Tritici in the Field

Nish¹,

Dodman²

1973

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“…Plants were washed and their roots examined under water over a white background for the presence of G. graminis (Garret 1941). As the plants were immature, this method was chosen rather than a bioassay (Mac Nish 1973). The percentage of infected plants per site was recorded.…”

Section: (B) At Cedunamentioning

confidence: 99%

“…The yield results for the 1970 crop were recorded. After the 1970 harvest, plants from a random selection of two sites per macro-row were removed and bioassayed (Mac Nish 1973) for the presence of G. graminis.…”

Section: (A) At Turretfieldmentioning

confidence: 99%

Incidence of Gaeumannomyces Graminis Var. Tritici in Consecutive Wheat Crops

Nish¹,

Dodman²

1973

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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.

“…The heads from the 144 sites in the three blocks were collected, threshed, and the grain weighed. Within each block the plants were removed from 12 sites (one site selected at random per drill row) and the crowns bioassayed for the presence of G. graminis (Mac Nish 1973).…”

Section: (A) At Turretfieldmentioning

confidence: 99%

Relation Between Incidence of Gaeumannomyces Graminis Var. Tritlci and Grain Yield

Nish¹,

Dodman²

1973

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A method of using grain yield to estimate the incidence of G. graminis var. tritici in the field is described. It was found that a map based on yield alone underestimated the actual incidence. However, when incidence and grain yield were coupled by the use of an "incidence-yield" regression established on a few sites, a map showing estimated levels of G. graminis var. tritici was obtained without destroying the experimental area. Bioassays of stubble and of soil cores were used to establish the actual incidence of G. graminis var. tritici; the former gave better results.