| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
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.
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