Agriculture Reference
In-Depth Information
Chapter 9
G ROWING W HEAT FOR H IGH A LCOHOL Y IELD -
H OMOGENEOUS AND
H ETEROGENEOUS A PPROACHES
J. S. Swanston and A. C. Newton
Scottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, UK
A BSTRACT
In the 1980s, Scottish grain distillers began to change from imported maize to home-
grown wheat as their preferred adjunct, requiring an annual intake in excess of 0.5
million tonnes. For ease of processing, soft-milling varieties were required, and low grain
protein contents were desirable. However, as this was a localised market, requiring a
small proportion of the UK wheat harvest, it received little attention from wheat breeders
until European interest developed in the use of wheat-based fuel ethanol as a partial
petrol replacement. A greater number of varieties with potentially high alcohol yields are
now being entered into national trials, but breeders face problems in early generation
selection for alcohol yield, as rapid testing procedures are still being developed, including
the use of Near Infra-Red Spectroscopy (NIR). Research to locate genetic factors
responsible for alcohol yield, on wheat chromosomes, is also at an early stage, although
this should facilitate the use of DNA-based selection systems in future breeding
programmes. Changes in the quantity and timing of nitrogen fertiliser may also be
necessary, as grain nitrogen content has a significant and negative effect on alcohol yield
and reduced inputs are also desirable to enhance the energy balance associated with fuel
ethanol production. However, these have to be achieved without a deleterious effect on
grain yield. As a number of current varieties have good alcohol yield potential, but may
have agronomic weaknesses, an alternative approach for cultivation is in the form of
varietal mixtures. Complex mixtures, i.e. those with four or more components, have also
been shown to increase grain yield and to reduce the spread of disease and thus the need
for prophylactic spraying of fungicides. Mixtures are also likely to provide greater
stability, across sites and seasons, for both yield and quality.
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