• Research in Plant Disease
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• v.25 no.3
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• pp.124-130
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• 2019

The study was conducted to investigate the infestation and distribution of plant-parasitic nematodes on Chinese yam (Dioscorea batatas) in Andong, Korea. Root-knot nematodes, Meloidogyne incognita was the most prevalent nematode species which is found from 43 yam fields (81.1%) with high population densities (average of 450 juveniles/$300cm^3$). Other nematodes, root-lesion nematode (Pratylenchus spp.) and pin nematode (Paratylenchus spp.) were less problematic. Density of juveniles (J2) of M. incognita was $10\;J2/300cm^3$ by August, then increased to 274 in September and 624 in October. The highest J2 density was found at the soil depth between 40 and 50 cm ($1,840\;J2/300cm^3$). M. incognita was able to infest yam tuber down to a depth of 70 cm and developed galls outside and brown spots inside. The highest number of females were found at 40-50 cm (79 females/10 cm piece) tuber from the top.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.362-372
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• 2000

This study was conducted to obtain the basic information on the production of high yield and qualitied yam in Andong, major yam-producing district, in Kyongbuk province, using three major Yam cultivars, such as Danma, Jangma and Alata (round type). Alata showed the longest tuber width while Jangma showed the longest tube length. Danma showed the highest tube yield at 2,123 kg/10a. Tubes of Alata had higher dry ratio than those of other cultivars, suggesting that Alata could be used as good processing materials. Characteristics of top parts, such as vine length, leaf number, and lateral vine number showed typical sigmoid curves. Tuber characteristics such as length, width and fresh weight of tuber were linearly increased as the growth period was progressed. Relative growth rate (RGR) for new tuber and stem reached the highest value at 86 DAT (days after transplanting). There were similar tendencies among the cultivars in net assimilation rate (NAR). The highest crop growth rate (CGR) was appeared at 156 DAT regardless of cultivars. In the changes of leaf area ratio (LAR), there were significant differences among three cultivars. LAR were decreased at 86, 106 and 136 DAT for Alata, Danma and Jangma, respectively. However, specific leaf weight (SLW) was greatly increased at 176 DAT, and leaf area index (LAI) was decreased at 156 DAT in all cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.144-150
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• 2014

Yams (Dioscorea spp), which are edible or medicinal tuber crops, are a important crop in South Korea. Yams require a high level of soil fertility. The various cultural practices such as fertilizing and plowing were tested for marketable tuber production in Chinese yam (Dioscorea opposita). Tuber yield was also affected by organic matters in soil. Application higher level of organic matters result in increased each tuber weight and tuber yield per unit area. The nutrient absorption quantity of the plant such as nitrogen, phosphoric acid, calcium and potassium was increased from 100~120 days after planting, which time to begin tuber enlargement. The tuber yield was increased when the fertilization increased in quantity. Total yield and marketable ratio were the highest in 31~32 kg/10a of nitrogen fertilizer. From above result, income become larger with increase of marketable yield and quality improvement at 63% (27 kg/10a) level of conventional N fertilization (43 kg/10a). The tuber yield was not significantly different between with in various application level of potash fertilizer. Tuber size and weight decreased accordingly to decreased fertilizing level, so the rates of small tubers increased greatly at cultivation without chemical fertilizer. In considering the accumulation rates of allantoin in Chinese yam tubers, the apt harvest season was after October. The allantoin quantity of it was not influenced with nitrogen fertilizing. Moreover it was advantageous with decrease of chemical fertilizer and appropriate fertilizing in soil environment protection. Commercial tuber's number and yield were increased in trenching before planting with trencher compared with rotavating with tractor.