Maize for Grain Hybrid Performance Update Disclaimer
The table below presents a summary of the possible t-test outcomes.
Interpretation of the t-test stars () for hybrid side-by-side yield comparisons.
INTERPRETATION OF PAIRED COMPARISONSWhere stars are shown below each comparison, this indicates the level of confidence that a real yield difference actually exists between the two hybrids based on the yield data. Yield superiority can only be concluded where one to three stars are present.
|P VALUE||CONFIDENCE LEVEL||SCIENTIFIC DESIGNATION||LEVEL OF SIGNIFICANCE||YIELD ADVANTAGE||INTERPRETATION|
|<0.001||>99.9%||Very highly significant||YES||Product superiority for yield is shown. Can confidently plant a product providing no key agronomic traits are limiting, and/or if a key trait advantage exists. Check the trait ratings for any considerations.|
|<0.10||>90.0%||CA||Commercially Acceptable||YES||Not a significant result, but may be regarded as commercially acceptable from which to base a decision.|
|<0.10||>90.0%||Not significant||NO||Product superiority for yield cannot be claimed. Ignore the yield comparison and refer primarily to trait ratings to select between the products.|
“The more stars () present for the comparison, the more confident we can be that the measured average side-by-side yield difference is due to an actual genetic yield difference between the two hybrids rather than just chance.”
Where a result is commercially acceptable (CA), the result is not designated as statistically significant, but it may be regarded as commercially acceptable. Where a result is not significant, we cannot conclude there is a yield difference between the hybrids. This may have two principle implications:
- Where the yields are very similar, and the comparison has been made over more than 20 locations, no significance may indicate there is little measurable difference between the two hybrids (i.e. they yield about the same) or;
- Where there appears to be a yield difference, no significance will generally indicate there are too few trial locations involved, or there have been inconsistent or fluctuating results. It is therefore, not possible to confidently indicate whether the difference is real. In this instance, growers should use the important hybrid trait ratings to select which hybrid to plant.
On the other hand, yields may appear to be very similar but still achieve significance - this happens in cases where yield variations are small and the number of trial locations is large.
A t-test analysis of statistical significance is now carried out on all Pioneer side-by-side comparisons and we take great care to base our product yield statements on the outcome.
The economics of growing maize for grain are largely dependent on costs, crop yield and the price received per tonne of grain. As a guide, the approximate fixed and variable costs to grow maize during the 2015/2016 season are indicated in the table below. These are indicative only and growers should carefully calculate their own costs and income in order to compute a more accurate analysis of the profitability of their own maize grain enterprise.
|COST/INCOME BASIS||COST PER HECTARE|
|Total costs (inputs & interest) ($/ha)||$2,530|
|Grain price ($/t) - 2015 harvest average||$370|
|Cartage ($/wet tonne)||$18|
|Drying ($/wet tonne) 24 to 14%||$40|
The profitability of each hybrid is calculated using the following assumptions:
- Total costs are a national estimation for the last growing season applicable at 1 January 2015.
- Total costs cover all establishment, growing and harvest costs.
- Cartage costs cover transport from the farm to the nearest, most commonly used dryer.
- Grain price is an assessed national average for the 2015/2016 season’s crop.
- Drying charges are the base cost for drying grain from 24% moisture to 14%.
- All prices exclude GST.
Hybrid profitability information is presented for all side-by-side comparisons and is intended to indicate the relative financial income difference per hectare between the two hybrids presented.
YIELD AT 14% MOISTURE
The yield of maize grain per hectare is normally expressed in tonnes at 14% moisture. Storage losses of maize grain are minimal once the grain moisture has reached 14%. The shrinkage factor of 1.35% adjusts the grain weight for losses associated with drying grain.
|Plot Area = plot length (m) x number of combine rows x row width (m)
Calculated Yield = wet yield x 10,000 x correction factor for moisture
Correction factor for moisture = 1 - ((harvest moisture - 14%) x 0.0135 (shrinkage factor))
Hybrid trial yields are often higher than is likely to be achieved in commercial paddocks, as the trial area measured and weighed is an even block within the maize crop. Commercial paddock yields are commonly around 10% lower as less productive areas including gateways, dry or wet patches, shaded portions and headlands are included.
* For more details on maize for grain economics click here