Effects of strobilurin fungicides on the milling quality of breadmaking winter wheat varieties

Summary

Sector:
Cereals & Oilseeds
Project code:
PR239
Date:
01 June 1999 - 28 March 2000
Funders:
AHDB Cereals & Oilseeds.
AHDB sector cost:
£27,919 From HGCA (Project Number: 2191)
Project leader:
N SAUNDERS & S SALMON by Campden and Chorleywood Food Research Association, Chipping Campden, Gloucestershire, LG55 6LD

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pr239-final-project-report

About this project

Abstract

Strobilurin fungicides are widely used within agriculture. They exert effects on both disease control of crop plants such as wheat and barley and increase yields. For this reason they now account for the majority of cereal fungicide treatments used in the UK, replacing the traditional triazole treatments which previously dominated fungicide usage. A number of strobilurin fungicide products are now available. Their precise mode of action is not known, but effects are largely preventative, as opposed to the curative effects offered by the triazoles. In practice, strobilurins are mixed with triazoles before application to crop plants, so that the relative merits of each are fully utilised.

Grain quality issues are a major concern for both the milling and processing industries, particularly in terms of protein content and alpha-amylase levels. There is little information available at present relating to the effects of strobilurin/triazole mixtures upon the subsequent quality of wheat samples. This study assessed the effects of a range of strobilurin /triazole applications on the subsequent quality of three wheat varieties.

This study was carried out in a season where there was severe pressure on wheat quality particularly in relation to alpha-amylase activity. Prolonged wet weather over the harvest period increased ear disease levels and provided crop protection challenges.

Aims

Assess milling quality to determine relative yields from each fungicide treatment for each of the three wheat varieties.
Examine whether any fungicide application leads to a "cleaner crop" by determining levels of Ochratoxin A, moulds, yeasts and viable counts on stored grain samples.
¨ Evaluate the effect on flour quality criteria e.g. protein and alpha-amylase content plus dough rheology.

¨ Assess breadmaking performance by the Chorleywood Bread Process, using loaf volume and crumb score as key quality indicators.

Conclusions and implications

There were clear differences between varieties for the majority of quality tests carried out.
The majority of wheat Hagberg Falling Number values were below 250s for Hereward and Rialto. This would cause rejection at mill intake and reduce subsequent processing options.
Fungicide treatments had relatively few significant effects on quality parameters that were confined to susceptible varieties. For example, individual fungicide regimes tended to reduce Falling Number values in Rialto and Hereward, but had no effect on the more sprout resistant Malacca.
A significant decrease in protein content was observed for Rialto under individual experimental fungicide regimes.
Extraction rates for Rialto differed significantly between fungicide treatments, but there was no difference between treatments for Hereward or Malacca.
¨ There were no clear differences in breadmaking quality between fungicide treatments for any variety tested.

There was no overall significant effect on the microbiological condition of grain samples resulting from any fungicide treatment. In general the variety Rialto, grown under the conditions of this trial, appeared to have slightly higher microbial counts than either Malacca or Hereward.
Ochratoxin A was not detected in any of the samples after a period of 20 weeks storage under standard conditions.

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