Walnuts from every angle: phenotyping by 3D Tomography
Fruits of temperate areas, walnuts too bear the impact of the climate change. In this context, walnuts producers need to find cultivars that provide fruits of quality. In collaboration with CTIFL (Technical Joint Trade Centre for Fruit and Vegetables) and INRAE (French National Research Institute for Agriculture, Food and Environment), a study was launched to achieve the morphological characterisation of walnut collections of INRAE.
The Physical Analysis laboratory of the French National Seed Testing Station at GEVES has developed a method for measuring various morphological features of walnuts by tomography and fully automated image processing. With this method, many important characteristics could be evaluated such as surface area, diameter, shell thickness, kernel volume and kernel/nut filling ratio, roughness, sphericity, etc. These measurements were obtained from reconstructed 3D images acquired by tomography. The fully automated image-processing workflow includes different steps: noise elimination, walnut individualisation, properties extraction and quantification of the different parts of the fruit. This method can be used regardless of the size and shape of the nut, and provides very precise measurements of the traits of interest.
This work has been published in an international peer-reviewed journal. The study has enabled our experts to enhance their skills involving this technology, adapted to the measurement of morphological characters of interest for seeds.