Characteristic of potato microtuber for seeds

利用受感染的种子感染病毒导致世界马铃薯产量严重减产，特别是在发展中国家，那里很难生产出合格的种薯。本研究的目的是评估试管种块茎在大田栽培中的产量潜力。用微型薯(MT)和常规块茎(CT)种子栽培4个不同成熟度的商品品种，历时2年。土壤、水处理(灌溉和不灌溉)从萌发后约30天开始在避雨处进行(DAS)。直到40天左右，MT植株的根干重(DW)和叶面积都小于CT植株。一年中严重干旱对植株生长的抑制作用，MT植株大于CT植株。但在地上部生长的高峰期(约80~90DAS)，两种植物的根干重和叶面积相似。在地上部生长盛期至采收期，MT植株的块茎干重增加幅度与CT植株相当或大于CT植株。土壤干旱对这一时期干物质生产的影响在MT和CT植株上没有差别。MT植株的相对块茎干重为CT植株的70~90%。早熟品种的相对干产量比晚熟品种小。本研究结果表明，尽管在干旱土壤条件下必须在早期生长季节灌溉，但对于难以生产合格种薯的国家来说，使用MT种子是有优势的。

A usage of infected seeds to virus results in severe yield reduction of potato in the world, especially in developing countries, where a production of certified seed tubers is difficult. The purpose of the present study is to evaluate the yield potential in the field cultivation using microtuber, which is produced in-vitro, for seeds. Four commercial varieties of different maturity classes were cultivated using seeds of microtuber (MT) and conventional sized tubers (CT) for two years. Soil, water treatment (irrigated and unirrigated) was conducted under rain shelters since about 30 days after sprouting (DAS). MT plants showed smaller root dry weight (DW) and leaf area than CT plants until about 40 DAS. The supression of growth due to severe drought in one year was greater in MT plants than in CT plants. At the maximum stage of shoot growth (about 80〜90 DAS), however, both plants had similar root DW, and leaf area. During the period from maximum shoot growth stage to harvesting stage, the tuber DW increase in MT plants was the same as or greater than that in CT plants. The effect of soil dryness on dry matter production during this period was not different between MT and CT plants. The relative tuber dry yield of MT plants to CT plants was 70〜90 %. Early varieties tended to make smaller the relative dry yield than late varieties. The present results indicated that a usage of MT seeds has an advantage for the countries where the production of certified seed tubers is difficult, although irrigation during the early growing season must be needed in dry soil condition.