Tropical Agriculture and Development
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Volume 61 , Issue 2
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Original Article
  • Masashi YAMAMOTO, Akihiro ITO, Aki SOGABE, Yuki KAJIWARA, Kiyotake ISH ...
    Volume 61 (2017) Issue 2 Pages 57-61
    Released: October 12, 2017
    JOURNALS FREE ACCESS

    Culture conditions for shoot tips excised from cutting propagated plants of acerola (Malpighia glabra L.) were investigated to develop a shoot-tip culture system. Shoot tips of acerola “Sanmikei (Hosoba)” were grown on a medium, consisting of MS basal components with 3% sucrose. The addition of 0.1 ppm 6-benzylaminopurin (BA), 0.05 ppm BA + 0.05 ppm zeatin or 0.1 ppm BA + 0.1 ppm zeatin was effective for the proliferation of shoots. Those that had grown two to three cm from the subculture, were examined further for rooting, which had been stimulated when the shoots were immersed in 250 ppm indole-3-butyric acid (IBA) for 15 seconds. Ten to eleven days of dark treatment enhanced this. All plantlets were recovered after acclimatization. Sequence-related amplified polymorphism (SRAP) was conducted to validate the genetic homogeneity of the regenerated plants. In SRAP analysis, using 13 primer combinations, no polymorphisms among the regenerated and original plants were detected.

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  • Hiroshi MATSUDA, Hirokazu HIGUCHI
    Volume 61 (2017) Issue 2 Pages 62-69
    Released: October 12, 2017
    JOURNALS FREE ACCESS

    We determined the temperature and humidity conditions during flowering that result in high germination of lychee pollen. Staminate flowers were gathered before anther dehiscence from the South Chinese cultivars ‘Tai So,’ ‘Souey Tung,’ Floridian ‘Bengal,’ and Thai ‘Chakrapat,’ and then incubated for 24 h at various temperature (15–30°C) and relative humidity [RH] (10–75%) combinations. After incubation, the percentage of dehisced anthers was recorded, and then pollen germination was tested. In all cultivars, dehiscence increased at higher temperature or lower humidity. The dehiscence exceeded 90% within 24 h at ≥20°C and RH <60%, except for ‘Souey Tung,’ for which it was generally below 80%. Germination of ‘Bengal’ was highest (≈50%) when the anthers dehisced at 20°C and ≈50% RH, and tended to decrease at higher and lower temperatures. The germination tended to decrease as humidity increased, and this tendency was remarkable at ≥25°C. ‘Chakrapat’ germination was also highest (≈60%) at 20°C and ≈50% RH. ‘Chakrapat’ germinated relatively well at 30°C. Relative humidity >30% affected germination slightly. Similarly, ‘Souey Tung’ and ‘Tai So’ had the highest germination (≈35% and ≈30%, respectively) at 20°C and ≈50% RH, although the germination was low. Similar to ‘Chakrapat,’ ‘ Tai So’ germination decreased slightly at higher temperatures, and was affected little by RH >30%. Pollen-tube elongation was also best at 20°C and ≈50% RH, and tended to decrease at higher temperatures or lower humidity. The optimal temperature/humidity conditions for lychee anther dehiscence were 20°C/≈50% RH, regardless of the cultivar.

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  • Kanae OYAMA, Putu SUDIARTA, Fumitaka SHIOTSU, Nobuo SAKAGAMI, Masakazu ...
    Volume 61 (2017) Issue 2 Pages 70-76
    Released: October 12, 2017
    JOURNALS FREE ACCESS

    Development of organic farming in Indonesia started in the 1980s, especially in Java. Recently we can easily find organic rice products at supermarkets in Indonesia, however, some products are not officially certified as organic agricultural products. According to the Bali Agricultural Agency, only 5 groups were certified for organic rice farming as of 2013. In this study, we interviewed organic and conventional farmers in a town in Bali and analyzed rice growth in their fields to reveal the benefits and difficulties of organic rice cultivation from economic and biological perspectives. In the interviews, all of the organic farmers indicated that they implemented organic systems because the production cost is less than that of conventional systems and the price paid to farmers for organic rice is higher than for conventional rice. Consistent with these replies, the calculated revenue/cost ratio of organic farming was significantly higher than that of conventional farming.

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  • Md. Abdul KARIM, Md. Abdul QUAYYUM, Sayed SAMSUZZAMAN, Hirokazu HIGUCH ...
    Volume 61 (2017) Issue 2 Pages 77-93
    Released: October 12, 2017
    JOURNALS FREE ACCESS

    Bangladesh has about one million hectares of char lands, i.e. lands develop along the riverbank and/ or on riverbed due to accretion of sediments. The chars are situated in the remote areas, and disadvantaged people are living therein. This study was conducted to gather information on soil characteristics, flooding pattern, existing crops and cropping and root problems for crop production in chars throughout Bangladesh. The information on different rivers’ chars of 10 Upazillas was collected and refined through Focal Group Discussion (FGD), Key Informant Interview (KII), and workshops. The land type and soil characteristics of the chars were depended on their age and distance from the river origin. Usually the north and middle region chars were sand or silt dominated, while the coastal regions’ were clay dominated. The crops and cropping varied largely due to the flooding pattern and land types. Flooding was very common in the northern and mid regions, though water logging and salinity prevailed in the coastal chars. In the Rabi season (November – March), a large number of crops were grown, especially in the northern and middle regions’ chars, though their productivity was rather low due to limited use of modern varieties, high irrigation and inputs cost, and non-ensured fare price of produces. Eight root problems of the chars were identified such as slow diffusion of technologies, unavailable inputs timely and absence of organized marketing system. The crop productivity is envisaged to enhance greatly by minimizing those problems.

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  • Jacob Anderson C. SANCHEZ, Jacqueline V. BAGUNU, Rubigilda P. ALILI, L ...
    Volume 61 (2017) Issue 2 Pages 94-98
    Released: October 12, 2017
    JOURNALS FREE ACCESS

    Foot and Mouth Disease (FMD) is a concern in many tropical and developing countries and pose a continuous threat in FMD-free nations such as Japan, Indonesia, and Singapore. A recent method being used to detect the virus is an RNA-based FMD detection kit. However, RNA can be easily degraded accounting to its shorter shelf life. In this study, RNA isolate from an inactivated vaccine, instead of the live FMD virus, was reverse transcribed and cloned to construct a more stable plasmid DNA. This innovation generated a template that can be stored for a long period and be used as a potential external positive control for DNA-based FMD detection kits. This study proves that the recombinant molecule containing 2B region of FMD virus genome can be used as an external positive control for RTPCR-based FMD detection and can be incorporated in test kits. Moreover, the constructed plasmid is stable for use after five months. Thus, there is no need to extract RNA from live FMD virus which makes the routine faster, convenient, and practical.

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