PROBLEM TO BE SOLVED: To solve a problem that an yellow chive is evaluated in its high-added value as the softening and whitening cultivation of a green chive, however, not generally diffused yet, and as its reason, there is listed a fact that a chloroplast is derived when the yellow chive is exposed to light after cultivated and changed into a green color, and thus, the yellow chive becomes difficult to be put into circulation, then, as the present measure, there is employed a method that the yellow chive cultivated in a dark place is exposed to strong sunlight, however, this method is subject to the weather because the strong sunlight becomes necessary at cultivation.SOLUTION: It is found that the generation of the chloroplast is suppressed when weak ultraviolet light is radiated to the yellow chive or the like which is cut at its on-ground root in advance. As an ultraviolet light source, a UV-sterilization lamp (UV-C, 200 to 280 nm) is used, and the ultraviolet light whose luminance is 60 to 500 μW/cm2 is radiated to a plant body for 10 min to 120 min. This method can be applied for the prevention of the greening of white asparagus, hirokko and white onion, the prevention of the greening of half-cut or quarter-cut celery cabbage and cabbage, and the prevention of the greening of a variety of kinds of beansprouts, sprite plants or the like in addition to the prevention of the greening of the yellow chive.COPYRIGHT: (C)2013,JPO&INPIT【課題】黄ニラは、青ニラの軟白栽培としての高付加価値が評価されているが、まだ一般的に普及されるまでに至っていない。その理由として、黄ニラは収穫後に光に当たると葉緑体が誘導され、緑色に変色するため、流通が難しいことがあげられる。現在の対策としては、暗所で栽培された黄ニラを強力な太陽光にさらす方法がとられている。しかし、収穫時に強力な太陽光を必要とするため、天候に左右されるという欠点があった。【解決手段】あらかじめ地上部を切除した黄ニラ等に弱い紫外線を照射すると、葉緑体の生成が抑制されることを発見した。紫外線源としてはUV殺菌灯(UV-C,200~280nm)を使用し、照度60μW/cm2から500μW/cm2の紫外線を植物体に10分間から120分間照射する。黄ニラ以外にホワイトアスパラ、ひろっこ、白ネギの緑化防止、2から4分割した白菜やキャベツの緑化防止、各種のもやしやスプライト等の植物の緑化防止に応用することができる。
