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Bogor, Indonesia

Dharmaputra O.S.,Seameo Biotrop | Putri A.S.R.,Bogor Agricultural University | Dewi A.U.,Bogor Agricultural University
Acta Horticulturae | Year: 2013

Colletotrichum acutatum is a pathogenic fungus causing bitter rot on fruit, including apple. Biological control of post-harvest diseases of fruit has emerged as a promising alternative to chemical applications. The objective of this study was to test the antagonistic potential of mycobiota of apple fruit ('Malang' and 'Manalagi') against C. acutatum. Fruit were collected from several traditional markets and supermarkets in Bogor and Jakarta, and from an orchard in Batu ('Malang'). Test fungi were isolated using a dilution method, followed by a pour-plated method on malt extract agar (MEA) containing chloramphenicol. The test of antagonism was conducted using the direct opposition method on MEA; the pathogenicity of test fungi was done by inoculating fungal isolates onto the two apple cultivars. The potential antagonistic fungus was evaluated by inoculating a 0.1 ml conidial suspension with different concentrations (1 × 106; 2 ×106; 4 × 106; 6 × 106; 8 × 106; 1 × 107 conidia/ml) onto the apples. Forty-nine isolates of test fungi were isolated from the apples. Eight out of 49 test fungal isolates inhibited growth of C. acutatum by more than 50%, and 6 out of 8 fungal isolates prevented disease developing on the inoculated apples. One of the antagonistic fungus, i.e., Pestalotiopsis guepinii with different concentrations of conidial suspensions were not able to control bitter rot effectively. Nevertheless, P. guepinii (4 × 106 conidia/ml) inoculated together with a 0.1-ml conidial suspension of C. acutatum (1 × 106 conidia/ml) inhibited bitter rot by 39.5%. © 2013 ISHS.

Sukmadjaja D.,Indonesian Center for Agricultural Biotechnology and Genetic Resources | Widhiastuti H.,Seameo Biotrop
Biotropia | Year: 2011

A study on propagation of three superior cassava (Manihot esculenta Crant) varieties i.e. Darul Hidayah, Malang-6 and Adira-4 through tissue culture technique was conducted at the Tissue Culture Lab of SEAMEO BIOTROP, Bogor. The objective of the experiment was to study effect of plant growth regulators on in vitro propagation, which can be used in cassava micropropagation protocol. Plant materials used were auxiliary shoots of a stem node. The experiment consisted of (i) shoot multiplication, (ii) roots induction, and (iii) acclimatization. The multiple shoot regeneration was observed by using Murashige & Skoog (MS) basal media supplemented with 0, 0.1, 1.0 and 5.0 mg/L of benzylaminopurine (BAP) combined with 0.0, 0.1 and 1.0 mg/L of thidiazuron. The root induction was observed by using 0.1 and 1.0 mg/L of IBA and NAA. The resulting plantlets were transplanted into plastic polybags containing soil mixed with organic fertilizer (1:1) covered with plastic sheets and transferred to a greenhouse. The result of the study showed that the highest number of shoots for Darul Hidayah, Malang-6 and Adira-4 varieties were 4.93 shoots treated with BAP 1 mg/L + thidiazuron 0.1 mg/L, 4.20 shoots at BAP media of 1 mg/L, and 7.20 shoots at the media of BAP 1 mg/L + thidiazuron 0.1 mg/L respectively. The highest number of nodes produced was 2.9 nodes for Darul Hidayah at BAP 5 mg/L, 5.13 nodes for Malang-6 at BAP 0.1 mg/L, and 6.18 nodes for Adira-4 at BAP 5 mg/L+thidiazuron 1 mg/L. The utilization of auxin IAA or NAA could induce and accelerate the growth of roots which finally could increase the success of acclimatization process. With an average of four multiplication factors of each culture period, the potency of each cassava shoot propagated through tissue culture could produce around 37 000 plants/year.

Pratiwi C.,Bogor Agricultural University | Rahayu W.P.,Bogor Agricultural University | Lioe H.N.,Bogor Agricultural University | Herawati D.,Bogor Agricultural University | And 2 more authors.
International Food Research Journal | Year: 2015

Aspergillus flavus (A. flavus) producing aflatoxin frequently contaminates crops such as soybeans. The growth of this mold on soybeans and other foodstuffs is affected by temperature and relative humidity (RH). The aim of this study was to measure the growth of A. flavus BIO 2237 and aflatoxin production at different temperatures and RH. Aspergillus flavus BIO 2237 was isolated from Indonesia origin foodstuffs. Aspergillus flavus BIO 2237 was inoculated in Czapek Dox Agar (CDA) and soybeans for 10 days at a temperature of 20, 30, and 40°C with RH of 70, 80, and 90%. Aflatoxin analysis was conducted using RP-HPLC equipped with fluorescence detector and post column photochemical reactor. The limit of detection (LoD) for aflatoxin of B1, B2, G1, and G2 was 0.45, 0.26, 0.05, and 0.13 ng/mL (ppb), while their limit of quantification (LoQ) was 1.50, 0.88, 0.18 and 0.43 ng/mL (ppb) respectively. The maximum growth for A. flavus BIO 2237 in CDA and soybeans was reached at a temperature of 30°C with RH of 90%, and this was based on the highest diameter of colony and amount of cell mass formed in that condition. The maximum level of aflatoxin in contaminated soybeans was found at 999 ng/g (ppb), and this was produced at the same condition as its fungi's growth. Aspergillus flavus BIO 2237 can not grow as well as produce aflatoxin in soybeans at high temperature (40°C) with low RH (70%). There was a significant difference (sig<0.05) in aflatoxin content (AFB1, AFB2, AFG1, and AFG2) between temperature and RH, meanwhile the difference on the growth of A. flavus BIO 2237 in CDA and soybeans caused by RH.

Ambarwati S.,Seameo Biotrop | Dharmaputra O.S.,Seameo Biotrop | Dharmaputra O.S.,Bogor Agricultural University | Retnowati I.,Seameo Biotrop
Biotropia | Year: 2011

A research on dietary exposure assessment for aflatoxin B 1 (AFB1) from processed peanut products in Municipality of Bogor was carried out. The objectives of this study were to determine the contents of AFB1 in processed peanut products at retail levels, and to obtain information whether there is a risk to public health caused by the consumption of processed peanut products contaminated by AFB1. Survey of processed peanut product consumption was carried out by interviewing each respondent using a questionnaire of weekly processed peanut product consumption. Sampling of processed peanut products was conducted at the locations where the respondents obtained processed peanut products. The number of roasted peanuts with skin pods, flour-coated peanuts and pecel or gado-gado sauces samples was 33, respectively, while the number of siomay and satai sauces samples was 18 and 12, respectively. The total number of processed peanut product sampleswas 129. AFB1contentwas determined using Thin Layer Chromatography method. Estimation of the dietary exposure assessmentwas determined using the actual survey data consisting of AFB1 content, consumption data and body weight. The highest contaminated sample percentage and mean of AFB1 content was found in roasted peanuts with skin pods i.e. 42% of 33 samples and 43.2 μg/kg, respectively, followed by flour-coated peanuts (30% of 33 samples and 34.3 μg/kg), and pecel or gado-gado (21% of 33 samples and 17.1 μg/kg). Mean of estimated dietary exposure for AFB1 found in children was 15.2 ng kg -1 bw day -1 and 95 th percentile exposure was 38.9 ng kg -1 bw day -1, while in adults 9.0 ng kg -1 bw day -1 and 95 th percentile exposure was 27.0 ng kg -1 bw day -1. The excess cancer risk of AFB1 exposure in Bogor from this study on children and adults was calculated as 193 and 115 cancers/year, respectively.

Dharmaputra O.S.,Seameo Biotrop | Dharmaputra O.S.,Bogor Agricultural University | Ambarwati S.,Seameo Biotrop | Retnowati I.,Seameo Biotrop
Biotropia | Year: 2012

The objectives o f this study were (a) to investigate the effect o f postharvest handling (threshing and storing) methods on the quality of sorghum (Sorghum bicolor (L) Moench) grains variety Numbu, in terms of the percentages of damaged grains and seed germination, population growth of Sitophilus zeamais, Fusariumproliferatum and F. verticillioides, fumonisin B, and carbohydrate contents, and the percentage of weight loss during storage. The change of moisture contents o f sorghum grains was also recorded. Threshing was conducted using wooden stick and a paddy thresher. Sorghum grains were packed in hermetic plastic bags. The conditions inside of the bags were airtight and normal. Each bag with different conditions inside was infested with 10 pairs of S. zeamais (1-14 days old). Sorghum was stored for one, two and three months under warehouse conditions. The results showed, that the moisture contents o f sorghum were lower than its standard safe moisture content (<14%) during storage. At the beginning of storage, the percentage of damaged grains caused by threshing using wooden stick was higher than that of using a paddy thresher. The increase of percentage o f damaged grains was caused among others by increase S. zeamais population under normal oxygen concentration inside of the bag (about 21%), consequently the percentage of weight loss was also increased. The percentage of seed germination of sorghum threshed using wooden stick was lower than that of threshed using a paddy thresher. The percentage of seed germination decreased with the increase of storage duration. Population of F.proliferatum and F. verticillioides decreased with the increase of storage duration. Fumonisin B1 content of sorghum threshed using wooden stick was higher than that of using a paddy thresher during one, two and three months o f storage. Fumonisin B1 contents were considered low. In general, carbohydrate content of sorghum threshed using either wooden stick or paddy thresher from the beginning up to three months o f storage were not significantly different. Threshing using a paddy thresher was better in comparison to threshing using wooden stick.

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