Characteristic of potato microtuber for seeds

将受感染的种子用于病毒导致世界马铃薯产量严重下降，特别是在发展中国家，因为这些国家很难生产经认证的种块茎。本研究的目的是评价利用离体生产的微块茎作为种子在田间栽培中的产量潜力。采用微块茎（MT）和普通块茎（CT）种子进行了为期两年的栽培，栽培了4个不同成熟度等级的商品品种。从发芽后约30天开始，在雨棚下进行土壤、水（灌溉和不灌溉）处理。直到约40 DAS， MT植株的根干重和叶面积均小于CT植株。一年内严重干旱对MT植株生长的抑制大于CT植株。在茎部生长高峰期（约80 ~ 90 DAS），两种植物的根重和叶面积相似。从茎部最大生长期到收获期，机栽植株块茎重增长量与CT植株相同或大于CT植株。土壤干燥对这一时期干物质产量的影响在轮栽和轮栽植株之间没有差异。MT植株相对于CT植株的块茎干产量为70 ~ 90%。早品种的相对干产量往往比晚品种小。目前的结果表明，尽管在土壤干燥的情况下必须在生长早期灌溉，但MT种子的使用对生产认证块茎困难的国家具有优势。

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.