492 G. GYULAI, I. ROVNER, S. VINOGRADOV, B. KERTI, A. EMÖDI, E. CSÁKVÁRI, A. KEREKES, Z. MRAVCSIK AND F. GYULAI Gyulai, G., Rovner, I., Vinogradov, S., Kerti, B., Emödi, A., Csákvári, E., Kerekes, A., Mravcsik, Z. and Gyulai, F. (2015), Seed Sci. & Technol., 43, 492-506. http://doi.org/10.15258/sst.2015.43.3.15 Digital seed morphometry of dioecious wild and crop plants – development and usefulness of the seed diversity index G. GYULAI 1 , I. ROVNER 1,2,3 , S. VINOGRADOV 4 , B. KERTI 1 , A. EMÖDI 2 , E. CSÁKVÁRI 2 , A. KEREKES 1 , Z. MRAVCSIK 2 AND F. GYULAI 2 1 Institute of Genetics and Biotechnology, St. István University, 2103 Gödöllő, Hungary (E-mail: gyulai.gabor@mkk.szie.hu) 2 Institute of Environment and Landscape Management, St. István University, 2103 Gödöllő, Hungary 3 214 Greensview Dr., Cary, NC 27518 USA 4 Institute of Economics, Law and Methodology, St. István University, 2103 Gödöllő, Hungary (Accepted July 2015) Abstract Seed populations of four dioecious plants, Taxus baccata (yew), Hippophae rhamnoides (sea-buckthorn), Diospyros virginiana (wild persimmon) and Asparagus officinalis (asparagus), were studied by digital morphometry using the Fovea Pro 4.0 computer program. In total, 20 of the 33 measured seed parameters were analysed and a new seed diversity index (SDI), based on the mean values of the relative standard deviations (%RSD) of measured values of seed parameters and seed morphological distances (SMD), based on Group Centroids of DA (discriminant analysis), were formulated. A CRT (classification and regression trees) diagram was found to reveal the most discriminative seed parameters. Histogram analysis was used to determine the ‘levels of domestication’ of the species by estimating the variations (‘force of mutation’; X-axis) vs. selection (‘force of selection’; Y-axis). These methods describing the homogeneity/heterogeneity of seed populations may be useful to introduce to Distinctness, Uniformity and Stability tests for plant breeders, growers and seed companies and for taxonomic research, and may also provide a method to separate large mixes or contaminated seed samples. Introduction Diversity (i.e., morphological variation) as a result of mutations is the basis on which natural selection operates to bring about evolutionary adaptation and survival of plant and animal species whether wild or domesticated (Rovner, 1995, 2007, 2011; Gyulai et al., 2006, 2014; Brinkkemper et al., 2011). Narrowing of morphological diversity in domesticated plant and animal species compared with their wild relatives as a result of both natural and human selection is well-known. It is also detrimental to the health and viability of plants, making them more vulnerable to diseases, pests and climate change. In contrast, inadequate variation can result in degradation and extinction of species. These phenomena raise problems of how to measure morphological variation within species, populations, individuals, organs or cells. Here we studied morphological variation of seeds of four dioecious plants, using digital morphometry data and variametric analysis.