Phenotypic evaluation of shape diversity in persimmon fruit using two- and three-dimensional imaging

A. Kusumi, Y. Osako, R. Nakano, S. Nishiyama, R. Tao
The demand for computer vision based fruit classification and evaluation techniques have been increased along with the rapid development of recent image processing technologies. Diospyros kaki exhibits a variety of fruit shape, including unique grooves in the lateral side and calyx end of the fruit. Here we first conducted 2D-based fruit shape analysis of 64 diverse persimmon cultivars using the SHAPE software. Major morphological diversity was summarized into small number of principal components, and we detected a component correlated with the depth of vertical groove. However, the groove-correlated component was also correlated with roundness of fruit. Thus, it was almost impossible to measure the groove depth and roundness independently based on the global dimension reduction method. We also applied 3D modeling of mature fruit to fully evaluate fruit shape. Here, the 3D structures of persimmon fruit were sliced at constant intervals, and the transverse section area and the convexity defects area were recoded for each section as the expression of the vertical groove depth. We confirmed that the genetic diversity in the pattern of vertical groove depth along lateral-side of the fruit could be represented by the proposed measurement method. This 3D imaging method appeared to be capable of capturing all the fruit shape information that could not be obtained by the conventional 2D-based measurement. In addition, it also appeared to be applicable for comprehensive morphometry, which can measure even complex shapes such as pattern of groove depth, of diverse persimmon fruit.
Kusumi, A., Osako, Y., Nakano, R., Nishiyama, S. and Tao, R. (2022). Phenotypic evaluation of shape diversity in persimmon fruit using two- and three-dimensional imaging. Acta Hortic. 1338, 263-268
DOI: 10.17660/ActaHortic.2022.1338.38
Diospyros kaki, genetic diversity, phenotyping, computer vision

Acta Horticulturae