Cotton variety selection is one the most important decisions affecting the grower’s bottom line. Once a variety is planted, the genetic yield potential for that particular field is set for that season. Beyond planting, it is up the grower’s management and the prevailing environment to preserve and maximize that potential yield.
Below are a few slides illustrating cotton variety performance in Dr. Edmisten’s 2014 Official Variety Trials (OVT) and On-Farm trials. These slides are derived from Dr. Edmisten’s earlier posts regarding Cotton OVT which can be found in this blog (http://cotton.ces.ncsu.edu/2015/01/phytogen-names-commercial-varieties/) and in the 2014 Cotton Information Book.
These slides will be discussed in further detail during the upcoming county meetings throughout February. Please see http://cotton.ces.ncsu.edu/events/ for dates, location, and times for county meetings near you.
The first slide illustrates cotton variety performance in each of the six 2014 OVT locations. The varieties are ranked in descending order based on their average yield across all six locations. Only the top 20 varieties are shown in this slide. Data within each of the six OVT locations can be seen in columns numbered 1 – 6. Within each trial (column), the highest yielding variety at that location is underlined. All varieties that performed statistically the same as the highest-yielding variety (statistically highest group) are highlighted in green.
Again, the varieties are ranked according to their combined average yield over all six locations. This format allows you to see how consistently a variety performed within the statistically highest yielding group, and in what type of environment. Some varieties may frequently perform very well (consistently highlighted in green) regardless of the environment in which it is planted. This indicates a high degree of stability across a number of factors including soil types, rainfall amount/frequency, planting dates, etc.
Other varieties may only be competitive in certain types of environments. Further to the right of this slide, you can see the combined average yield over all locations. All varieties highlighted in green in this column performed with the statistically highest group in the combined analysis. The two columns furthest to the right illustrate the percentage of trials in which a variety was the number 1 variety, and the percentage of trials in which a variety performed within the statistically highest group. Again, this will be discussed in further detail during the upcoming county meetings.
As varieties are released onto the market in a very rapid manner these days, it is important to observe multi-year data in order to make the best variety decisions. Varieties that perform well across several years also indicate a high degree of stability. Growers are encouraged to try brand new varieties, but only on a limited basis, as there is a lot of risk in planting a large acreage to varieties that have not been adequately tested in replicated trials. The second and third slide illustrate cotton variety performance in Dr. Edmisten’s 2-year and 3-year OVT analysis. Only the varieties that performed in the statistically highest group are shown.
The final slide illustrates average cotton variety performance across Dr. Edmisten’s three on-farm trials during 2014. Varieties highlighted in yellow indicate performance within the Top 3 varieties in at least 2 of the 3 on-farm trials. Varieties highlighted in green performed within the Top 3 varieties in at least 1 of the 3 on-farm trials.