Seedlings

It refers to a relatively young plant body used for cultivating crops, and is called a seedling for herbaceous plants and a sapling for woody plants. Seedlings are generally seedlings grown from seeds, but there are also clumped seedlings, grafted seedlings, cutting seedlings, and layered seedlings. In addition, as in the case of sweet potatoes, the stems that sprout from seed potatoes and do not have roots are also called seedlings.

Seedlings are usually grown intensively in a seedbed and then planted in the main field once they reach a certain size. Since the young seedlings are susceptible to external influences when they germinate, the purpose of seedlings is to artificially protect and grow them in a seedbed during that period, and then plant them in the field once they have acquired resistance. Another purpose is to grow seedlings earlier than the natural growing season and transplant them as soon as the outdoor temperature becomes suitable for growth, in order to speed up growth and harvesting. The quality of the seedlings affects the growth and yield of the plants after transplanting, so the cultivation of healthy seedlings has long been considered important in crop cultivation, to the extent that it is called "half-cropping seedlings." A good seedling (healthy seedling) is one that has good roots, a thick stem, leaves that are neither too pale nor too dark, grows firm without becoming too elongated, and is free of pests, diseases, and injuries.

[Hoshikawa Kiyochika]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

作物の栽培に利用する比較的幼い植物体をいい、草本性植物については苗、木本性植物については苗木とよぶ。苗は種子を播(ま)いて育てる実生(みしょう)苗が一般であるが、株分(かぶわ)け苗、接木(つぎき)苗、挿木苗、取木苗などもある。またサツマイモの場合のように、種(たね)いもから芽生えた茎を切り取った、根のついていないものでも苗とよんでいる。

　苗は普通苗床で集約的に管理して育て、一定の大きさになってから本畑に定植する。種子が発芽した幼若期は外界の影響を受けやすいので、その時期を苗床で人工的に保護して育て、抵抗力がついてから畑に出すのが苗の目的である。ほかに、自然の作期より早いうちから苗を育て、露地が生育可能気温になったらただちに移植して生育と収穫を早める目的などもある。苗の素質は移植後の植物の生育や収量に影響を及ぼすため、昔から作物栽培では苗半作とよばれるほど、健苗の育成が重要視されている。よい苗（健苗）とは、根張りがよく、茎が太く、葉は淡くもなく濃すぎもせず、徒長しないで堅めに育ったもので、病虫害や傷害のないものである。

［星川清親］

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