Morphometric descriptors and random amplified polymorphic DNA (RAPD) markers were used for the classification of acerola cultivars ‘Okinawa Sweet’ and ‘Kagoshima Sweet’ grown in Okinawa and Kagoshima Prefecture, respectively by comparison with seven cultivars introduced from Hawaii into the germplasm bank of Japan International Research Center for Agricultural Sciences (JIRCAS) . Even though cultivar identification could not be achieved by using morphometric descriptors, all the genotypes were classified according to RAPD-based DNA analysis using 57 RAPD markers amplified by 24 primers. Genetic similarities between all the pairwise combinations of cultivars were calculated using Jaccard's coefficient, which ranged between 0.00 to 1.00 with a mean value of 0.304, and 0.077 to 0.967 with a mean value of 0.406 for the morphometric descriptors and RAPD markers, respectively. RAPD similarity coefficients were correlated with morphometric similarity coefficients (r=0.578, p<0.01) . The relative position of different cultivars in a RAPD-based dendrogram was partly similar to that in a dendrogram between morphometric descriptors. The RAPD-based dendrograms revealed that the 9 cultivars could be classified into two groups. Four cultivars namely, ‘Hawaiian Queen’, ‘Manoa Sweet’, ‘Kagoshima Sweet’, and ‘Okinawa Sweet’, were clustered very closely, indicating the presence of a narrow genetic variability among them, based on both marker types.

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In previous studies, fertilizer application to sago palms cultivated in peat soils did not appreciably improve the growth of sago palm. We applied ca. 7 times the general rates of nutrients (N, P, K, Ca, Mg, Cu, Zn, Fe and B) to sago palm cultivated in peat soils at Riau, and evaluated the response of the roots and aboveground biomass during the 16 months period following the fertilization (2 dry seasons and 1 wet season) . The dry weight of the sago palm roots with fertilizer was smaller than that at the onset of the experiment, whereas the sago roots without fertilizer was similar in dry weight to the initial ones. The response of the aboveground biomass to fertilization differed among organs, i.e., the dry weights of the leaves, rachis, and trunk did not differ significantly between the palms with and without fertilizer application, while those of petioles and suckers were significantly greater in the palms with fertilizer. The percentage of the dry weight of mother palm in the total dry weight decreased linearly with increasing the dry weight of suckers, which ranged from 74% to 57% for the palms with fertilizer versus from 85% to 79% for the palms without fertilizer. This observation indicates that the application of fertilizer accelerated the accumulation of dry matter in suckers rather than in mother palm.

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The present study was carried out in the East Sepik province, Papua New Guinea. The objectives of the study were to describe the present situation of agriculture of each study site, and to clarify “the local characteristics of indigenous agriculture” by carrying out comparative studies on local agricultural techniques and knowledge. The data were collected in field surveys conducted over a periods of 3 months, from October to December 2003, in addition to extensive research carried out since 1991. It appeared that various techniques as well as knowledge reflected the local characteristics (topography, history and dietary culture, etc.) in each study area. Investigations on crop diversity showed that the number of food crops based on folk classification in cultivated land increased in proportion to the dependence on food supply from shifting agriculture fields. On the other hand, although several techniques were common among the areas, this situation was not always in complete accordance with the local farmers' intentions. In other words, indigenous knowledge and techniques did not always conform to agricultural science. It appears that the indigenous agriculture practiced in the study area reflected the adaptation to and changes in the “living subsistence activities” corresponding to various historical changes, and never stemmed from immutable tradition.

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Seasonal variations in fruit characteristics and relationships among them in keraji (Citrus keraji), which is a local cultivar mainly grown on Kikai-jima island, Kagoshima prefecture were studied.
Although the fruit of Keraji was inferior to that of satsuma mandarin (C. unshiu) in terms of coloration of skin, the titratable acidity of Keraji was almost the same as that of ‘Okitsu wase’ which is an early ripening clone of satsuma mandarin. The Brix value of Keraji which was slightly higher than that of ‘Okitsu wase’, increased until early February. Sugars in the juice of Keraji consisted of fructose, glucose and sucrose. Sucrose was the predominant sugar component, followed by glucose and fructose in mature fruit, and this composition was similar to that of many citrus accessions. On the other hand, the juice of Keraji showed characteristic acid constituents. The content of citric acid in juice decreased rapidly during the growth period, while the content of malic acid increased gradually from October. Consequently, the malic acid content was approximately 40% of the citric acid content in January and February. The contents of polymethoxy flavones (PMFS) which are characteristic phytonutrients of citrus in the juice of Keraji was almost the same as those of Ponkan (C. reticulata), one of the species with the highest PMF contents. On the other hand, the PMF contents in the peel were lower than those of Ponkan and Shiikuwasha (C. depressa) .
A positive correlation was revealed between the number of leaves, diameter of the peduncle and rind texture, and fruit weight. Generally fruits with coarse rind and good coloration display a low and high Brix value, respectively. The fruit weight was negatively correlated with the titratable acidity, but not significantly with the Brix value. The correlation between the number of seeds per fruit and the fruit weight was not significant.

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Greater yam (Dioscorea alata L.) seldom flowers, sets few seeds and is propagated by tuber. As a novel technology for efficient propagation, the development of an efficient tissue culture system would be basically significant.
In the present study, the effects of the application of phytosulfokine-α (PSK-α), which is expected to become a novel plant growth regulator, and other plant growth regulators on callus induction and on plant regeneration were investigated using two accessions of D. alata, Okinawa-san A from Okinawa, Japan and Sulka, introduced from Papua New Guinea. Calli were induced from the petioles of in vitro-grown plantlets when the explants were cultured on solid MS medium supplemented with 30g1^-1 sucrose, 2mg1^-1 2, 4-D and 2g1^-1 gellan gum in darkness at 28°C in both accessions. In Sulka, shoot differentiation was observed after the calli were transplanted to fresh media supplemented with various combinations of 2, 4-D and BA under a 16 hr. photoperiod with a light intensity of 50.4μmol m^-2s^-1 at 28°C. However, no shoot differentiation was observed in Okinawa-san A. Callus induction in Okinawa-san A was promoted by the addition of PSK-α, especially at 20nM, and shoot differentiation was induced after 2 months on the media supplemented with 5, 10 and 20nM PSK-α. PSK-α was not effective either for callus induction or shoot differentiation in Sulka. The results revealed intra-specific differences in the response to the growth regulators between the two accessions of D. alata. The alleviation of callus browning by the addition of PSK-α to the media suggested that PSK-α may enhance the potential of shoot differentiation from callus, which was lost by the stress experienced on the media lacking PSK-α.

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Present status of an integrated farming system, referred to as VAC system in Vietnam, was surveyed in the Mekong Delta (Vietnam) . The survey was conducted through interviews of farm households in My Loc Village, Tam Binh District, Vinh Long Province. Approximately 70% of the surveyed households were registered as operating RVAC farms, which produced rice in the integrated farming system. Twenty percent were registered as operating rice monoculture farms, which mainly produced rice, and the others were registered as operating VAC farms, which did not produce rice in the integrated farming system. However, differences in the products and productivity were not significant among the RVAC farms and rice monoculture farms, except for the amount of total production, and farmers in the village produced a variety of products, including rice, fruits, fishes and animals, regardless of the registered system. As for the characteristics of these products, rice production depended on the area and the market price remained stable. Production of fruits was restricted by the labor force, though the price fluctuations were wide and a higher income could be expected. Fish which could be produced at a low cost, were used for home consumption, while high production could be achieved from a small area in the case of livestock. Farmers in the village produced a variety of products combining the characteristics of each product and wanted to enhance fruit and animal production. Assuming that the area of cultivated land per household is likely to decrease in the Mekong Delta, increase of fruit and animal production can be predicted.

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In Japan, some pesticides have been detected frequently in imported Thai fresh vegetables such as okra. Although the okra problem was resolved by improved production and inspection systems, other vegetables still often contain chemical residues. In the present report, we surveyed the current status of the Thai measures implemented to minimize the contents of chemical residues in fresh products.
Thai government requested exporters to accept the products for export, according to the Thai governmental GAP (Good Agricultural Practices) Standard. Since the okra exporters have generally concluded contracts with the farmers, they can easily follow the regulations. In contrast, it is difficult for the exporters to deal with other products in the same way as with okra, because they obtain these products from wholesale markets and/or multiple distributors and, therefore, they cannot ask farmers directly to improve their farming systems. Therefore, the Thai government is in charge of the final check system to detect chemicals before export. Presently, Thailand promotes exports of fresh fruits and vegetables which are mainly distributed in domestic markets and it is likely that unsafe products are still being exported. Therefore, Thailand should improve the production systems and food safety assurance schemes.

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