NatioNal variety trials supplemeNt - Grains Research ...

variety will yield on-farm – it varies from
paddock to paddock and year to year.
The NVT trial network exposes varieties
to a range of growing environments
experienced across multiple sites and
seasons. The analysis of data across
multiple environments gives a ranking
of how varieties perform in a given
environment and shows how stable this
ranking is across other environment types.
Growers and advisers are encouraged
to look at long-term data across a range
of sites that are applicable to their own
situation, irrespective of the distance
of these sites from their property.
How can small plot trials be
accurate enough to inform
variety decisions at farm-scale
A fair comparison of varieties can
only be made when they are grown
under the same conditions. This is
especially difficult in large-scale plots
due to the extent of variation in soil
characteristics across the paddock.
Small plot trials provide the best
opportunity to test varieties under
similar conditions as it minimises the
effect of large-scale field variation.
Small plot trials in combination with
modern statistical methods have been
well established as the most accurate
way of performing variety evaluation.
Most of the district was sown
dry. Why were the NVT trials
not dry-sown
The biggest risk to dry seeding is a
false break. Small amounts of rain
may germinate the seed but then the
soil dries out, causing the seedlings
photo: Emma Leonard
NVT site visits can be arranged by contacting the trial site manager. Details of the
locations and contacts for all trials can be found at www.nvtonline.com.au
to die. Often this happens to only part
of the seed sown, with the remainder
germinating following later rains.
A trial with patchy establishment is
useless for varietal yield comparison. In
comparison, a patchy crop in a commercial
paddock may allow plants to branch and
compensate to achieve adequate yield.
By mid-May, the likelihood of
a false break is reduced; after this
time trials may be sown dry.
How are NVT site locations
selected
The location of NVT sites evolved
from the state department of agriculture
variety trials that were conducted prior
to 2005. Trials are generally located in
each of the production zones of a state
although not on a pro-rata basis.
As well as providing regional
adaptation information, the NVT trial
sites also form a hub for many grower
discussion groups and this can drive
the choice of location for some sites.
However, as new statistical
technologies come online, the ability
to define and maintain the ‘must-have’
sites for the scientific evaluation of
varieties will be greatly improved.
This new analysis will provide greater
flexibility for NVT sites to be located at
grower group field day sites and other
locations frequently visited by growers. □
GRDC Research Codes CAS00002,
UW00006
More information: www.nvtonline.com.au
7
NVT structure and operation
FIGURE 1 Varietal comparisons from the 2010 NVT main season wheat trial at Spring Ridge, NSW
Yield (t/ha)
8
7
6
5
4
3
2
1
0
Sunstate
Peake A
Sprayed
Lincoln A
Orion A
Dakota A
Unsprayed
EGA Bounty A
Kennedy A
Sunvale
Janz
Spitfire A
EGA Wylie A
Livingston A
Ventura
Error bars indicate the maximum SED for any combination of varietal yields. Consequently, a lack of overlap of any two error bars indicates a significant difference in yields.
Ellison A
Sunco
Sunzell
EGA Stampede A
GBA Ruby A
Sunvex A
Lang A
QAL2000
Chara A
GBA Hunter A
EGA Wills A
Merinda A
EGA Gregory A
Crusader A
Gladius A