Discriminant method with image data to select the plant with superior characteristics from interspecific hybrids of Dioscorea species
1990
Shibusawa, S. (Hokkaido Univ., Sapporo (Japan). Faculty of Agriculture) | Terao, H. | Araki, H. | Yakuwa, T.
The analysis of tuber shape with digital image data was applied to the selection of lines with superior characteristics from hybrids between D. opposita and D. japonica. The interested lines with superior characteristics seemed to be slenderer in the hybrids, then the shape parameters to evaluate the slenderness were calculated and used for the discriminant analysis. The ratios of tuber widths were used for the one of the discriminant methods. The tuber width was obtained from the intersections of the tuber outline and a circle with its center at the middle point of tuber. The tuber widths of 80 were sampled on the CRT image data along the tuber axis. The other method was the application of Fourier series to the representation of tuber outline. The Fourier series description gave a good approximation of the slender tuber shape. Next combinations in the shape parameters the discriminant analysis: 1) The initial gradient of tuber width from the middle point toward the trunk part. 2) The initial gradient of tuber width from the middle point toward the neck part and the ratio of tuberwidth at the points of one-fourth and middle to tuber. 3) Three kinds of ratios of tuber widths at the points to divide the tuber into four equal parts. In the case of Fourier coefficients of the width curve, next variables gave the accurate solution by the discriminant analysis: 4) The constant term and the coefficients of first harmonic number
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