A Study of a Non-destructive Measurement Method for Judging the Growth Stage of Gentian for Flower Harvest and Quality Control

在龙胆切花中随机存在的授粉花被认为是造成龙胆整体市场价值下降的主要原因。由于常以原色铜色变色进入市场，整体花形变质的风险很大，因此在收割单位装运后要及时摘除授粉花朵。然而，在目前的情况下，大多数农民只能通过观察外观来检测它，并手动将其移除。岩手县的主导品种‘Ashio no Natsu，Gentiana sp.’的幼花与田间刚授粉的花有明显的差异，移除授粉的花相当不充分。另一方面，即使在这种情况下，少数熟练的农民也可以在仔细检查外观的情况下检测到授粉的花。然而，为了推广它们的技术，有必要客观地阐明它们的感官和主观区分方法。在本研究中，以‘龙胆，龙胆’为对象，利用简化的测量装置，从红外可见光波长仔细观察了幼花和授粉花花瓣外表面的光谱辐射差异。结果表明，在波长为720 nm附近有显著差异。因此，在不久的将来，由于在大多数商用摄像机中使用的普通图像传感器CCD对该波长具有敏感性，因此有可能开发出廉价的授粉花早期检测装置。

The pollinated flower, which exists randomly in a cut flower of Gentiana Sp., is known as the main cause which decreases market value of the whole. Because it often arrives to market with color changed in copper from its original color, the risk that deteriorates figure of the whole is very high.Because of this reason, it is necessary to remove the pollinated flower promptly after harvest unitl shipment. However, under present circumstances, most farmer should detect it only with observation of appearance and remove it manually. Therefore, some pollinated flower should be left usually.On 'Ashiro no natsu, Gentiana sp.', which is the leading kind in Iwate prefecture, apparent difference between the young flower and the flower which has just pollinated in field is so subtle that removal of the pollinated flower is considerably insufficient. On the other hand, even on this kind, a few skillful farmers are possible to detect the pollinated flower with careful inspection of appearance. However, to spread their technology, it is necessary to elucidate their sensuous and subjective distinction method objectively.In this study, targeting 'Ashiro no natsu, Gentiana sp.', difference of spectral radiance on the outer surface of petal between the young flower and the pollinated flower was examined closely from visible wave length over infrared with a simplified measuring device. As a result, a significant difference was ascertained especially in the wave length of 720nm neighborhood. Thus, in the near future, it will be possible to develop early detection device of the pollinated flower by picture photographing inexpensively, because the CCD, which is commonplace image sensor used in most commercial video camera, has sensibility to this wave length.