馬鈴薯毒素病之研究 1．馬鈴薯X毒素病田間檢定

Abstract

The cultivation of Irisn potato in Taiwan is centered in the middle part of the island. Climate conditions at this part of the island in winter time are suitable for growing of potatoes. According to the Agricultural Year Book of 1965 edition, areas of 1,165.3 hectares out of the total potato producing areas of 1,305.55 hectares are located in this part. A Japanese variety, Norm No. 1 is the major variety of cultivation. The average yield per hectare is 12 metric tons, only half the yield of potato production in the European countries. Since healthy table-stocks of local multiplication are not available, most tubers for planting are imported annully from Japan. It is necessary to self-supply healthy seed tubers in order to avoid possibly snaeking in of some plant viruses or strains of potato viruses new to this island. Toward the object of successful local multiplication of healthy seed tubers for sufficient fulfillment of demand, an attempt to obtain potato virus X (PVX) free seed-tubers had been made. Serological methods was employed to examine the distribution of the virus, morever, for the field inspection and the roguing of infected plants. In January, 1965, examinations of PVX distribution among the potato plants from seed tubers of Norm No. 1 of different origins was carried out at five locations in the middle part of the island. The results showed that potato plants from seed-tubers newly imported from Japan are less infected by PVX than those from locally multiplied seed tubers. Average of 68.5% of newly imported tubers and 83.5% to 89.5% of locally multiplied tubers from different origins were infected by the virus. Efforts had also been made to secure the source of PVX free seed-tubers by roguing infected plants. Field inspection for PVX by means of serological diagnosis, mainly chioroplast agglutination had been carried out three times at a upland branch of an Agricultural Experimental Station located in the northern part of the island, where the elevation is 1,000 meters (3,280 feet). Only seventy one PVX free plants were obtained from 7,216 plants examined in the first trial. About 43% and 60% of tuber units were healthy in the second trial and third trial, respectively.