The 2012 ASHS Annual Conference

Computer-based analysis of digital images has been used to objectively characterize morphological variation found in plants, including shape and color of leaves, flowers, and fruit.  Tomato Analyzer^TM (TA) is a free software initially developed for rapid, high volume analysis of tomato fruit morphology as well as color, using digital images generated with flat-bed scanners. Application of TA has expanded to describe fruit quality in avocado (Persea) and grapes (Vitis) as well as for embryo size in seeds of cucumber and other Cucurbitaceae..  We have used TA to examine flower and leaf traits in 128 accessions of Viola, including nearly 100 cultivars of V. xwittrockiana as well as putative progenitor species such as V. tricolor, V. altaica and V.corsica.  We have also been using TA with Phlox species native to Eastern North America (P. paniculata, P. pilosa, P. divaricata, etc.) to assist us in identifying products of interspecific hybridization experiments.  For each accession 4 plants had 5 flowers scored for 28 traits describing shape (e.g., height to width ratio, area to perimeter, etc.); size, and color. We have found TA to be a robust and useful tool for phenotypic analysis of flower traits that can then be compared with genotypic analysis of the plants.   Significant differences were detected in flower/petal shape, size and color of Viola accessions using ANOVA, and grouping by Principal Coordinate Analysis and Neighbor-Joining trees created distinct clusters mainly by color and size in Viola, but by species in Phlox.  We found little variability in the analysis of leaf morphology of Viola, but useful differences in the leaves of Phlox.  The capability of such speedy, large volume analysis could be a valuable tool to botanists delimiting species, populations, and individuals by objectively describing various character traits.  Similarly, horticulturalists and plant breeders could score variation between cultivars or advancements over generations in a breeding program.  As seen in tomato, the pairing of objectively scored, quantitative traits, such as those described by TA, with molecular data could be a powerful method in describing the patterns of variation in germplasm collections of ornamental plants.