• Journal of Bio-Environment Control
• /
• v.23 no.4
• /
• pp.376-382
• /
• 2014

This work was conducted to investigate the variation of growth and yield among three generations ($TC_0$, $TC_1$, and $TC_2$) in the field cultivation of virus-free sweetpotato (Ipomoea batatas) plants. Virus-free generations of three cultivars ('Matnami', 'Shinhwangmi', and 'Yeonhwangmi') were cultivated with $75{\times}25cm$ planting density on May 20th, covered with black vinyl film. At 30 days after planting, vine growth in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant, and vine length in $TC_0$ showed the highest growth among treatments. At harvesting time after 120 days, vine diameter, number of node, and number of branch in $TC_0$, $TC_1$, and $TC_2$ were more increased than farmer's plant, but were not statistically significant. Fresh weight of shoot in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant, but was not statistically significant among generations or cultivars. Number of tuber per plant and mean weight of tuber in $TC_0$ and $TC_1$ showed significant increasement, but that in $TC_2$ did not show significant difference as compared to the farmer's plant. Weight of tuber per plant in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant. Marketable yield, percentage of marketable tuber, and percentage of small tuber (40 to 200g) in $TC_0$, $TC_1$, and $TC_2$ was significantly increased as compared to the farmer's plant. The large tuber over 300g showed the lowest percentage in $TC_0$. Marketable yield in $TC_2$ was significantly decreased as compared to $TC_0$, and was not significantly different as compared to the farmer's plant. Marketable yield in 'Matnami' was highest among cultivars. From this results, Farmers are required to renew every three years to maintain the yield and quality of virus-free plants. However, the exchange period of virus-free plants is desirable to renew every 2 or 3 years according to the degree of virus reinfection.

• Korean Journal of Organic Agriculture
• /
• v.15 no.1
• /
• pp.109-121
• /
• 2007

For developing standard method for diease, pest and weed control in environmental friendly 'Ssam' vegetable cultivation, this study was carried out to investigating agriculture material use in organic agriculture and no pesticide cultivation for lettuce, kale, leafy perilla and korean cabbage. The 28.6% of investigated farmer carried out seed sterilization by seed selection with salt solution and soaking in chitosan that not validated. For raising seedling periods, the 55.6% of farmer did not use environmental-friendly agriculture material for, diease control and the 50% of farmer used one time for. pest control. Therefore, the control of disease and pest could be achieved with one or two times use of environmental-friendly agriculture material. Seed sterilization was carried out by soil solar sterilization, one time per year in 71.4% of farmer. Weed was controled by black PE film for weed germination of furrow in many farmer, by man-power weeding for weed of ridge in 85% of farmer and by machine weeding and mulching in some farmer. During cultivation period, the major pest were Aphis gossypii in lettuce, Plutella xylostella in kale, Plutella xylostella and Phyllotreta striolata (Fabricius) in korean cabbage and Pyrausta panopealis (Walke) in feat perilla. The many farmers used environ-mental-friendly agriculture material for control of pest over 10 times for spring season, and more used sold materials in market than home-made materials. In result, it needs to develop standardized method and validate cultivation methods for control of disease and pest, and seed sterilization treatment environmental-friendly 'Ssam' vegetable.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.4
• /
• pp.491-497
• /
• 2015

Small-sized tuber of sweet potato (Ipomoea batatas Lam.) is more preferred by Korean consumers, because it is convenient to eat with hands, and can easily be steamed or roasted in small pan as a healthy snack for a small family. The present study was aimed to investigate the effect of high-density plantings and harvesting times on production of smallsized tuber (50~200 g). Four varieties ('Annobeny', 'Daeyumi', 'Shinzami', and 'Yeonhwangmi') were planted in 2-row zigzag high-density planting ($75{\times}30cm$, A; $75{\times}25cm$, B) and 1-row planting ($75{\times}25cm$, control) covered with black vinyl film on May 23th, 2014. Marketable yields and small-sized tuber yields were compared between 120- and 150-day harvesting. Vine length and fresh weight per plant were significantly decreased in 2-row planting A and B plots compared to the control at 120 days after planting. Weight of tuber per plant, mean weight of tuber and number of tuber per plant were significantly decreased in 120-day harvesting of A and B plots than in the control. Marketable yields per 10a were increased by 17% ($2.4ton{\cdot}10a^{-1}$) and 8% ($2.6ton{\cdot}10a^{-1}$) in 120-day harvesting of A and B plots compared to the control ($2.4ton{\cdot}10a^{-1}$), and those were largely increased by 29% ($4.0ton{\cdot}10a^{-1}$) and 26% ($3.9ton{\cdot}10a^{-1}$) in 150-day harvesting than in the control ($3.1ton{\cdot}10a^{-1}$). Proportions of small size tuber (50~200 g) were increased by about 65% in 150-day harvesting of A and B plots compared to the control (55.3%). Small-size tuber yield and marketable yield were highly increased in 150-day harvesting of 2-row zigzag high-density planting A ($75{\times}30cm$).