Seed Yield and Lodging Assessment in Red Fescue (Festuca rubra L.) Sprayed with Trinexapac-Ethyl

Red fescue (Festuca rubra) is used in seed mixtures for lawns and pastures. It is prone to lodge at flowering, and plant growth regulators (PGRs) are used to prevent lodging, ensuring sufficient pollination. Seed yield and lodging were studied over three years in a red fescue field established with four seeding rates (2, 4, 6 and 8 kg ha−1) and sprayed each year with three doses of the PGR trinexapac-ethyl (250 g L−1) (0, 0.3, 0.6 and 1.2 L ha−1). Half of each plot was sprayed with the PGR and the other half was left unsprayed as control. The degree of lodging was assessed by analysing drone images in the second year of the experiment and using a 10-point scale for scoring lodging at the ground. Generally, application of PGR increased the seed yield but the effect varied between years. There was no interaction between the PGR dosage and seeding rate. We found a positive correlation between the blue intensity of the images and lodging. PGR dosage significantly affected lodging evaluated by visual ranking and the blue intensity of the images, while the seeding rates did not affect lodging. Lodging affected seed yield negatively.

Comparison of Proximal Remote Sensing Devices for Estimating Physiological Responses of Eggplants to Root-Knot Nematodes

Proximal remote sensing devices are becoming widely applied in field plant research to estimate biochemical (e.g., pigments or nitrogen) or agronomical (e.g., leaf area, biomass, or yield) parameters as indicators of stress. Non-invasive characterization of plant responses allows for the screening of larger populations faster than conventional procedures which, in addition to requiring more time, either imply the destruction of material or are subjective (e.g., visual ranking). This study explores the comparison of a set of remote sensing devices at single-leaf and whole-canopy levels based on their performance in assessing how the eggplant and its yield responds to grafting as a way to tolerate root-knot nematodes. The results showed that whole-canopy measurements, such as the Green Area (GA) derived from the Red-Green-Blue (RGB) images (r = 0.706 and p-value = 0.001**) or the canopy temperature (r = −0.619 and p-value = 0.005**), outperformed single-leaf measurements, such as the leaf chlorophyll content measured by the Dualex (r = 0.422 and p-value = 0.059) assessing yield. Moreover, other parameters, such as the time required to measure each sample or the cost of the sensors, were taken into account in the discussion. In sum, indices derived from the RGB images demonstrated their robust potential for the assessment of crop status as a low-cost alternative to other more expensive and time-consuming devices.

An evaluation method for print mottle using wavelet denoising and image grey level intensity gradient

Print mottle is observed as an unevenness of printed tone across an image area. There are many causes of mottle on typical print media, i.e. printing and writing papers, packaging and board, as well as foils and polymer surfaces amongst others, in both applications of traditional printing techniques, such as offset and flexography as well as digital methods, including inkjet and electrophotography. Causes range from inhomogeneous surface chemistry and absorption characteristics to instability factors on the printing press. Since the phenomenon is both physical and aesthetical, providing an evaluation for comparison purposes is challenging, frequently requiring panels of observers to provide a visual ranking. A new evaluation method is proposed using wavelet denoising and grey level gradient analysis of the print image. The index of print mottle is built on the bases of the average of grey level gradient and its distribution standard deviation. The method was tested for print mottle evaluation on paper in specific situations under different image basis functions and decomposition level. The results show that the method is in good agreement with visual assessment, and is also less time consuming both in the process and in statistical analysis, with correlation coefficient (r2) of at least 0.79 and as high as 0.88 with every function basis (level 2 or 3).

PRINTING.Paper and printer effects on xerographic print quality

This study examines the impact of paper and printer type on the quality of xerographic prints. Ten different uncoated paper substrates were printed using three different commercial xerographic printers. The print quality of the samples (print microgloss, print microgloss nonuniformity, print density, print and gloss mottle, and visual ranking) and the physical and surface characteristics of the papers were measured. It was found that relationship between print mottle and print gloss nonuniformity was dominated by the printer type. While for some printers, these two parameters were positively correlated, in other cases printer appeared to "mask" variations in the paper properties. Multivariate analysis also showed that brightness, opacity, basis weight, 7 5 ° Tappi gloss, and roughness were the top five paper properties that had the most significant effect on the visual ranking and print mottle. Finally, as expected, print roughness was found to be a better predictor of the perceived print quality, however, paper roughness was poorly correlated with the visual ranking of printed samples (R2 0.5).