Short communication. Tomography as a method to study umbrella pine (Pinus pinea) cones and nuts

Abstract

Aim of study: Umbrella or stone pine (Pinus pinea) nuts are one of the most valuable and expensive non-wood forest products in Portugal. The increasing market and landowner's interest resulted on a high expansion of plantation areas. This study tests the feasibility of using tomography to characterize pine cones and nuts.Area of study: The research was carried out in pine stand, with nine years, grafted in 2011, on Herdade of Machoqueira do Grou, near Coruche, in Portugal's central area.Material and methods: Starting in June 2015, ten pine cones in their final stage of development, were randomly monthly collected, and evaluated with tomography equipment commonly used in clinical medicine, according to Protocol Abdomen Mean. A sequence of images corresponding to 1mm-spaced cross-sections were obtained and reconstructed to produce a 3D model. The segmented images were worked using free image processing software, like RadiAnt Dicom Viewer, Data Viewer and Ctvox.Main results: The cone's structures were clearly visible on the images, and it was possible to easily identify empty pine nuts. Although expensive, tomography is an easy and quick application technique that allows to assess the internal structures, through the contrast of materials densities, allowing to estimate pine nut's size and empty nut's proportion. By analysis of ninety images, it was obtained, an estimated mean value of 25.5 % empty nuts.Research highlights: Results showed the potential of tomography as a screening tool to be used in industry and research areas, for analysis and diagnostic of stone pine cone's structures.

Variability of stone pine (Pinus pinea L.) fruit traits impacting pine nut yield

“…In Chile, where L. occidentalis have only been recently detected, the observed variability should not be confused with the effect of pest infestation. The decrease in cone to pine nut yield is particularly relevant because companies usually buy cones by their weight rather than by pine nut content; determining cone to pine nut yield has still not been possible to date, even though serious attempts have been made (Nunes et al 2016).…”

Recommendations for increasing yield of the edible Pinus pinea L. pine nuts

“…In the last decades, a severe reduction of cone to seed yield (from 17% to 5%) and PY (from 4% to 2%, or even less) has been reported in Europe [13], with apparently healthy cones containing up to 50% of empty seeds. This fact is relevant, since companies buy cones by weight instead of pine nut content [14]. Thus, the importance of PY monitoring has increased due to the growing presence of empty and damaged seeds [15], which was attributed to biotic (Leptoglossus occidentalis, [16,17]) and abiotic damage (droughts, [13,17]).…”