Quantifying fruit shape is challenging, particularly when measurements are made on segregating populations of plants that vary greatly in shape. Objective manual measurements can be performed on small samples of fruit, but this method is not feasible when dealing with larger samples or when shape variations are slight and continuous. Also, subjective rating scales can be utilized, but they are less effective when done by multiple raters due to varying descriptive standards among individuals. Therefore, we have developed a method to analyze digital images containing multiple fruits to characterize fruit shapes. Each segregant of a population of table grapes with parents of significant varying shapes was photographed and analyzed. Image pixels representing fruit were selected and evaluated for area and perimeter, which were subsequently used to calculate a shape factor and compactness value. This was a reasonably simple and quick method for quantifying grape berry shape, giving the researcher valuable phenotypic data in numerical form. This technology should be useful for shape characterizations of other fruits as well.
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