Variation of the normalised temperature for each genotype ranked by mean temperature.

<p><b>A</b>) Graphical representation of the consistency of the rankings of the different genotypes across three measurement dates for Trial 4. The genotypes are ranked along the x-axis according to the mean of all the replicate normalised genotype temperatures (°C) over three days. The X-axis also indicates the positions for the two parents (HB171, 99FT1b5) and two commercial varieties (Var1 = Record and Var2 = Cara). <b>B</b>) The same data as (A) but with data randomly assigned to ‘genotypes’ independently on each day, indicating the range of genotype means that could have arisen by chance. This confirms that the substantial genotypic differences in mean normalised temperature shown in (A) are not due to chance. LSD values presented at 95% level in all graphs.</p

Genotype temperatures and harvest traits.

<p>Relationship between normalised genotype temperatures (mean of three days) for Trials 4 and 5 and harvest traits (Yield, Plant height and Maturity) represented using regression lines in the plots. The numerical figures displayed provide the correlation coefficients and the <i>p</i> values for the plotted traits.</p

Visual (RGB) image and corresponding thermal image of part of the potato field trial.

<p><b>A</b>): Visual image of the randomised potato field trial showing markers to aid localisation in the thermal image. The marked circle indicates one of the two-plant plots. <b>B</b>) Corresponding thermal image; this shows the selected area of canopy for each plot isolated in the ThermaCAM Researcher Pro software.</p

Canopy temperature (°C) variation within images and between successive images.

<p>Dot plot covering measurements on three trials on a single day showing the substantial temporal variation, with the major reduction in temperatures between images 34 and 42 resulting from variability in environmental components. Each cross represents the temperature of a single plot in one image.</p

Correlation between trials.

<p>A representative extract from the full matrix showing both the correlations between normalised genotype temperatures (represented as °C) for different trials and measurement days and the associated correlation coefficients.</p

Effect of replication and normalisation.

<p>Illustration of the benefits of image overlaps and of normalisation for calculating the genotype means during thermal image analyses (using the example of Trial 4_Day1 data). The two replicates are indicated using different symbols. <b>A</b>) Relationship between individual plot temperature (IPT) on y-axis and Genotype Means. <b>B</b>) Relationship between the “individual-image normalised plot temperature” (IINPT) and Genotype Means. <b>C</b>) Relationship between Normalised Plot Temperature (NPT) and Genotype Means. Note: Residual errors as a measure of the difference.</p

An example of field trial layout showing the imaging strategy.

<p>The sequence of images is illustrated showing the overlap between images with many plots having repeated measurements. Each plot in the plan contains a single genotype plot (2 or 5 plants). So a single trial with 192 genotypes replicated twice has 24 rows of 16 plots.</p

Consistency in genotype ranking at different times and at different physiological ages.

<p><b>A</b>) Contour plots illustrating the consistency in genotype ranking for normalised genotype temperature (genotype means) between different trials on the same day but measured at different times (Trial 2, 3, 4 and 5 on Day 2, imaged between 9:00 am to 12:30 pm, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065816#pone.0065816.s001" target="_blank">Table S1</a>). <b>B</b>) Contour plots illustrating the consistency in genotype ranking for normalised genotype temperature between different days for one trial (Trial 4 on day1 (28/06), day2 (05/07) and day3 (12/07/2011)). The arrows in (B) correspond to the positions of the 20 genotypes each rank extreme in (A) with dotted arrows indicating the coolest and solid arrows the hottest. Data are expressed as genotype rankings on each occasion (x-axis indicating genotype numbers), with black areas indicating genotypes ranked among the hottest on any occasion and white areas indicating genotypes ranked among the coolest.</p