An approach for the symbolization of colors in rice plant and its adoption for the classification of rice varieties

Abstract

In order to make it possible to identify rice varieties, some pigments in rice plants of 630 varieties collected from fifteen countries were observed. For the sake of this observation, the authors have adopted MUNSELL'S color system of which descriptions are considered to be properly objective than the ordinary system. The frequency of appearance of pigments in fourteen characteristics in rice plant is very high in the inner part of leaf sheath, internode, septum, apiculus and stigma at heading stage and in apiculus at maturity stage. Especially, the anthocyanin pigments are observed in all the characteristics in rice plants, while no other pigments are observed in all the characterstics except in the following fcur characteristics ; namely, septum and pulvinus or node at heading stage and apiculus, Iemma and, palea at maturity stage (Table 1). The symbolized color shown according to MUNSELL's 'color system for each charccteristic in rice plant shows a wide range in the hue, value and chroma for the characteristics of septum at heading stage, and apiculus and lemma or palea at maturity stage. The hue shown by MUNSELL'S color system in rice plant is expressed by RP, R, YR and Y, and the anthocyanin pigments are limited to RP (Table 2). In regard to anthocyanin pigments in characteristics of rice plant the data obtained show similiar tendencies to the previous reports (Fig. 1). Taking these results into consideration, only five charctersitics were finally selected for the purpose of the possible discrimination of rice varieties ; namely, innerpart of leaf sheath, septurn and apiculus at heading stage and apiculus, Iemma or palea at maturity stage. Besides MUNSELL'S color system, a method of showing color in numerals was adopted, and the classification of about half of the rice varieties having color pigments was accom-plished by this method (Table 3).