Taiwan Agricultural Research Institute Council of Agriculture, Executive Yuan
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Detection of Male Oriental Fruit Fly (Diptera: Tephritidae) Susceptibility to Naled- and Fipronil-Intoxicated Methyl Eugenol
No full textNaled-intoxicated methyl eugenol (ME) is commonly used to control oriental fruit flies, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), in Taiwan. However, non-responsiveness to ME and pesticide resistance in oriental fruit flies may reduce control efficacy. In this study, mark-recapture experiments were used to analyze the effects of naled-intoxicated ME on field and naled-resistant fly strains. ME non-responsiveness was tested in field, naled-resistant, and susceptible strains and pyrosequencing techniques were used to detect frequencies of point mutations on organophosphate resistant alleles in field strains. Finally, the effects of fipronil-intoxicated ME were analyzed to determine whether control efficiency could be enhanced through the use of alternate pesticides. Control efficiency of naled-intoxicated ME was found to be significantly lower in the field and resistant strains compared to the susceptible strain. ME non-responsiveness was found to be 1.7-1.9% in our lab-reared strains (both naled-resistant and susceptible) and 3.4-4.3% in field strains. Results of our pyrosequencing study found frequency of resistant alleles in captured male field flies to be significantly lower than that of the original population, indicating that it is highly probable that resistant flies may escape from traps. Finally, capture rates of naled-resistant flies increased when naled was replaced with fipronil in attractants, showing that use of pesticides with different modes of action could possibly increase control efficiency of intoxicated ME attractants
Newly recorded diseases of ornamental plants caused by Phytophthora palmivora in Taiwan
No full text在台灣，自1999年至2015年於田間採集擬似疫病菌危害之觀賞作物標本，共發現與鑑定8種由Phytophthora palmivora引起的台灣觀賞作物疫病新紀錄。罹患疫病的8種觀賞寄主植物包括：軟枝黃蟬、洋桔梗、長壽花、含笑花、桂花、杜鵑花、鵝掌藤及美女櫻等。發病部位包括花、葉、嫩莖及根系組織，嚴重時導致病株全株萎凋、枯萎死亡。本實驗共分離到37株P. palmivora（7A^1:30A^2）菌株，均為典型菌株（typical type）。孢囊為單假軸著生，橢圓形、卵圓形或檸檬形，兩側大致對稱，具明顯乳突與脫落性；藏卵器表面平滑，藏精器單生單室底著；具厚膜孢子。生長溫度最高可達34－36℃，最適生長溫度為24－28℃。ITS DNA序列與收集在NCBI GenBank資訊庫中P. palmivora的相同度高達99.49－100%，屬於Cooke等人分子分類群的第IV群（clade）。本試驗結果顯示P. palmivora基因序列的比對結果與形態鑑定結果具一致性。
From 1999 to 2015, diseased samples caused by Phytophthora species were collected from gardens and fields in Taiwan. A total of 8 species of ornamental crops infected with Phytophthora palmivora were identified and recorded for the first time in Taiwan. These 8 species of ornamental crops infected with Phytophthora consisted of campanilla (Allamanda cathartica), prairie gentian (Eustoma exaltatum ssp. russellianum), kalanchoe (Kalanchoe blossfeldiana), banana shrub (Michelia figo), sweet osmanthus (Osmanthus fragrans), azalea (Rhododendron sp.), umbrella tree (Schefflera arboricola) and garden verbena (Verbena hybrida). Among these plants, sever disease symptoms were observed on prairie gentian and azalea. A total of 37 isolates (7A^1:30A^2) of the P. palmivora infecting these ornamental plants were obtained. All of them showed typically morphological characteristics of P. palmivora. Sporangia were produced simple sympodiumly on sporangiophores, and ovoid, oval to lemon-shaped, symmetrical or slightly asymmetrical on both sides, papillate prominently, and deciduous. Oogonialwalls were smooth and antheridia were amphigynous. Chlamydospores were abundant. Maximum temperature for mycelial growth was 34-36℃, with optimum temperature at 24-28℃. The sequences identities of ITS DNA region of these isolates were up to 99.49-100 % with the best fit sequences of P. palmivora collected in NCBI GenBank database, and these can be classified as Phytophthora clade IV (Cooke et al. 2000). Blasting results of these P. palmivora isolates were consistent with morphological characters
Methods on the isolation and cultivation of Pythiogeton species
No full text本實驗建立能有效自環境中分離亞腐黴菌之半選擇性培養基，以馬鈴薯葡萄糖瓊脂培養基為基礎，分別添加鏈黴素、撲克拉與免賴得800、1與1 ppm，可減少細菌與真菌的干擾；並藉由亞腐霉菌在此培養基的菌絲及特有菌落形態，可與其它卵菌做出區隔，能在被其他真菌及卵菌生長覆蓋前，順利將標的亞腐霉菌移植純化出來。亞腐黴菌在此培養基菌落呈稀疏狀、菌絲內的原生質無明顯顆粒與空隙，在光學顯微鏡下呈現油亮狀。利用此培養基進行亞腐霉菌的分離，發現有病徵之茭白組織、及浸泡於水中的茭白或水稻之莖葉殘體容易分離得到亞腐霉菌。而從台灣各種作物之水田可分離得不同種之亞腐霉菌，於茭白筍田可分離Pythiogeton abundans、P. microzoosporum、P. oblongilobum、P. puliense、P. ramosum 及P. zizaniae；於水稻田可分離得到P. abundans 及P. ramosum；P.microzoosporum、P. oblongilobum、P. puliense 及P. zizaniae；於水甕菜田可分離得到P. uniforme；於菱角田可分離得到P. paucisporum 及P. proliferatum。上述9 種亞腐霉菌的菌絲皆在裸麥瓊脂生長最佳，除了P. zizaniae 需要在裸麥瓊脂加茭白筍萃取液與組織塊之外，其他8種亞腐霉菌可在裸麥瓊脂繼代培養，而此9種亞腐霉菌在裸麥瓊脂最適生長溫度為28或32 ˚C。無論在瓊脂或液體培養基，除了P. ramosum 之外，其他的供試菌皆不產生氣生菌絲，且菌絲多生長於培養基底部。本研究的結果顯示，亞腐霉菌普遍存在於台灣的水田裏。
A semi-selective medium for isolating Pythiogeton species was established by using PDA as a basal medium supplemented with 800 ppm streptomycin, 1 ppm prochlorate, and 1 ppm benomyl. This medium is designated as modified potato dextrose agar (MPDA) and could efficiently suppress most undesirable microorganisms during the process of isolation. For Pythiogeton growing on MPDA colonies are sparse, and hyphae have no conspicuous granular particles or large vacuoles and appear glassy and refractive under microscope. This type of hyphae is distinct and can be easily recognized on MPDA. The right hyphae of Pythiogeton can be picked up and transferred before other fungi or oomycetes overgrow, which makes the isolation of Pythiogeton efficient. In the isolation test using MPDA, Pythiogeton species can be easily obtained from necrotic tissues of living water bamboo and plant debris of water bamboo and rice. Different Pythiogeton species were isolated from Taiwan paddy fields. Pythiogeton abundans and P. ramosum were isolated from water bamboo and rice; P. microzoosporum, P. oblongilobum, P. puliense and P. zizaniae were isolated from water bamboo; P. paucisporum and P. proliferatum were isolated from water caltrop; P. uniforme was isolated from water convolvulus. When these Pythiogeton species were cultured on agar media, rye sucrose agar (RSA) was the optimal medium for mycelial growth of these Pythiogeton species, except for P. zizaniae, which was optimal on RSA supplemented with both extract and tissues from water bamboo. The optimal temperatures for the mycelial growth of these 9 Pythiogeton species on RSA were 28 ˚C or 32 ˚C. Apart from P. ramosum, Pythiogeton species produced no aerial mycelia on solid and liquid media, and mycelia usually were imbedded within the media. This study revealed that Pythiogeton species are actually common in paddy fields, and could be cultivated once proper approaches are applied
Availability of Near Infrared Reflectance Spectroscopy for Determining the Chemical Components and Quality in Rice
No full text本研究利用由日本、美國及東南亞等地區收集之秈稻品種共24個，稉稻品種共29個為材料，在一期作於嘉義農業試驗分所試驗田種植，試驗主要目的在探討理化特性，諸如米飯物理特性（texture）、白米粉末黏度特性（viscosity）、貯藏性蛋白質及胺基酸等共40項理化特性與近紅外光吸收光譜之關係，並針對近紅外線分析技術（technique of near infrared reflectance spectroscopy，NIRS）推定米質之可行性進行探討，結果發現NIRS光譜吸收值與米理化特性間關係相當密切，利用19個NIRS波長吸光值轉化成19個主成份（principal component）後，再以19個主成份對各品質性狀進行逐步迴歸分析，結果於食味官能品評特性中，外觀、口味、黏度及食味總評之模式其複相關係數（R）分別為0.912、0.938、0.951 及0.961；而以6個物理特性建立之模式其複相關係數（R）介於0.558～0.819之間，其中黏性模式之解釋率最高（0.819）；12個黏度特性迴歸模式之複相關係數（R）介於0.554～0.940之間，其中以尖峰黏度之糊化始溫值（0.913）、破裂黏度（0.918）、相對破裂率（0.938）及破裂率（0.940）模式之解釋率較高，複相關係數（R）均達0.91以上；4種貯藏性蛋白質迴歸模式之複相關係數（R）介於0.63～0.869，其中以globulin迴歸模式解釋率較高（0.869）。18個胺基酸建立迴歸模式之複相關係數（R）介於0.565～0.894之間，其中除了色胺酸、異亮胺酸、甲硫胺酸及精胺酸等4種胺基酸之迴歸模式的複相關係數（R）低於0.80 外，其餘14種胺基酸之迴歸模式的複相關係數（R）均大於0.82。進一步以複相關係數（R）高於0.8之模式其米理化特性之預測值對食味總評值進行逐步迴歸分析，結果發現利用NIRS米理化特性預測值可解釋食味變異達91％。又利用NIRS 波長吸光值所轉化之主成份亦可解釋食味變異達92.4％，顯示以NIRS推定食味變異應是可行之途徑。
24 indica and 29 japonica rice varieties (53 in total) collected from Japan, America and southeast Asia were available in this study. By the courtesy of Chia-Yi Experiment Station, TARI all material were grown at that station in 1st crop season. The main objectives of this study were to determine the relationships between physicochemical properties and the absorbance of 19 NIRS wavelength. And to elucidate the feasibility for using near infrared reflectance spectroscopy (NIRS) on the assessment of rice grain quality. The results obtained by correlation analyses and stepwise regression analysis between the physicochemical properties and NIRS were summarized in the followings:The results were showed that the absorbance of 19 NIRS wavelength have close relationships with physicochemical properties, and the absorbance of 19 NIRS wavelength were transformed by principal components analysis and were regressed on the physicochemical properties by stepwise regression analysis. The results showed that the values (R) of multiple correlation coefficients were 0.912, 0.938, 0.951 and 0.961 for appearance, flavor, cohesion and overall sensory evaluation of palatability, respectively. The range of multiple correlation coefficients was 0.558~0.819 for texture traits of cooked rice. In this range, viscousness was found to be the highest (0.819) among the six texture traits. The values of multiple correlation coefficients ranged from 0.554 to 0.940 for 12 viscosity traits of milled rice and the gelatinization temperature of peak viscosity (0.913), breakdown (0.918), relative breakdown (0.938) and breakdown ratio (0.940) showed the highest four R values among the 12 viscosity traits. The values of multiple correlation coefficients ranged from 0.630 to 0.869 for 4 storage proteins of milled rice and the golbulin (0.869) showed the highest R value. Except tryptophan, isoleucine, methionine and arginine, all of the values of multiple correlation coefficients for other 14 amino acids were higher than 0.82. The predicted values of physicochemical properties in the models showing 0.8 or higher multiple correlation coefficients were selected to establish the palatability equation by stepwise regression analysis. The results indicated that the predicted values of physicochemical properties could explain 91% of variation of overall sensory evaluation. However, the principal components transformed from the absorbance of 19 NIRS wavelength could explain 92.4% of variation of overall sensory evaluation. These results showed that the NIRS might be used for determining the eating quality of cooked rice
