首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:从到   被引次数:从到   他引次数:从到 提示：输入*表示无穷大
全文获取类型
  收费全文   32篇
  免费   1篇
专业分类
林业   6篇
农学   1篇
  12篇
综合类   3篇
农作物   3篇
水产渔业   5篇
畜牧兽医   1篇
植物保护   2篇
出版年
  2023年   1篇
  2022年   3篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   8篇
  2016年   3篇
  2013年   3篇
  2010年   2篇
  2008年   1篇
  2005年   1篇
  2003年   1篇
  2002年   1篇
  1989年   1篇
排序方式： 共有33条查询结果，搜索用时 234 毫秒
1.
Potato is one of the most important crops in the world, including in the tropics. Potato requires low temperatures or cool climate for optimum tuber yield, which in the tropics, can be obtained mostly in high altitude growing areas. The limitation of land availability for potato production in highland areas of some tropical countries has steered the recent development of potato production to medium altitude areas. The objective of our study is to identify potato accessions with promising levels of heat resistance in laboratory and with good adaptation to medium altitude in the field. We used in vitro assay to screen a number of potato clones with possible resistance to heat stress on the basis literature and database of the International Potato Center, supplemented with the collection of Bogor Agricultural University. We then continued with verification of selected clones using field test in high altitude (1300 m above sea level) and medium altitude (700 m above sea level) areas. Our result showed that there is considerable variation of S. tuberosum for their adaptation to medium altitude areas in the tropics that can be exploited in breeding programs. We identified one genotype PKHT 2013-06 that was superior for its ability to produce tubers under extreme conditions. Thus, it might be very suitable to be used in a breeding program to develop tolerant varieties of potato to medium altitude areas in the tropics.  相似文献   
2.
The potential insecticidal activity of Spilanthes acmella Murr. (Compositae) extracts was assessed in this study. The extracts were shown to be toxic against adults of American cockroach, Periplaneta americana L. The active component in S. acmella extract was isolated and identified as N-isobutyl-2,6,8-decatrienamide (spilanthol). The results from topical application of spilanthol show that it has a high acute toxicity and spilanthol was the most potent compound when compared to three conventional insecticides. The potency was found to be 1.3, 2.6 and 3.8 times more toxic than carbaryl, bioresmethrin and lindane, respectively. Electrophysiological studies indicated immediate hyperexcitation followed by complete inhibition of the cockroach cercal nerve activity.  相似文献   
3.
Journal of Plant Diseases and Protection - Leaf blight is one of the most serious threats to rice agroecosystems worldwide, and the yield reduction due to this disease can be as high as 70%. For...  相似文献   
4.
Paddy and Water Environment - In this study, we focused on the effect of the degree of floc growth on the moving velocity of the interface between sediment of flocculated montmorillonite and...  相似文献   
5.
The anionic nature and high cation exchange capacity (CEC) of clinoptilolite zeolite can be exploited to reduce ammonia (NH3) loss from urea and to improve soil chemical properties to increase nutrient utilization efficiency in lowland rice cultivation. A closed-dynamic airflow system was used to determine NH3 loss from treatments (20, 40, and 60 g clinoptilolite zeolite pot?1). Seed germination study was conducted to evaluate the effects of clinoptilolite zeolite on rice seed germination. A pot study was conducted to determine the effects of clinoptilolite zeolite on rice plant growth variables, nutrient uptake, nutrient recovery, and soil chemical properties. Standard procedures were used to determine NH3 loss, rice plant height, number of leaves, number of tillers, dry matter production, nutrient uptake, nutrient recovery, and soil chemical properties. Application of clinoptilolite zeolite (15%) increased shoot elongation of seedlings and significantly reduced NH3 loss (up to 26% with 60 g zeolite pot?1), and increased number of leaves, total dry matter, nutrient uptake, nutrient recovery, soil pH, CEC, and exchangeable Na+. Amending acid soils with clinoptilolite zeolite can significantly minimize NH3 loss and improve rice plant growth variables, nutrient uptake, nutrient recovery, and soil chemical properties. These findings are being validated in our ongoing field trials.  相似文献   
6.
In this work, the effects of various operating parameters (pressure, pH, BPA concentration, and filtration time) toward bisphenol A (BPA) removal via ultrafiltration (UF) membrane system were investigated using response surface methodology (RSM). Historical data design of RSM was used to obtain the interaction between variables and response as well as optimizing the process. The analysis of variance (ANOVA) showed that the third-order polynomial model was significant in which pH and filtration time were identified as significant terms that influence BPA removal. The 3D response surface plots revealed the two-factor interaction between independent and dependent variables. The optimization process of the model predicted optimum conditions of 99.61% BPA removal at 1 bar, pH 6.7, 10 μg/L BPA concentration, and 10-min filtration time. The predicted optimum conditions for BPA removal were consistent with the obtained experimental values, indicating reliable application of historical data design RSM for modeling BPA removal in UF membrane system.  相似文献   
7.
Phosphorus is an essential element required to maintain profitable crop production. Most soils of the tropics, such as Ultisols, are acidic and fix phosphorus because of their characteristically high contents of aluminium and iron. Compost and biochar could be used to mitigate phosphorus fixation by reducing the phosphorus sorption sites. This study aimed to: (i) improve soil phosphorus availability, nutrient uptake, and yield of maize using biochar and pineapple leaf residue compost; and (ii) determine if the use of biochar and compost could exert a residual effect on phosphorus nutrition in the second cycle of the field trial. Field trials were carried out using a Zea mays L. hybrid as the test crop. At harvest, the plants were harvested, partitioned into leaves and stems, and analyzed. Soil samples were also collected and analyzed. Ears were harvested to determine the yield from each treatment. The results suggest that the soil total phosphorus and available phosphorus recovered from the treatments with the organic amendments were higher compared with the non-organic amendments. The availability of soil nutrients (nitrogen, potassium, calcium, magnesium, and sodium) in the soils and yield of maize were higher in the treatments with the organic amendments in the first and second field trials. These results further confirm that amending chemical fertilizers with organic amendments have a larger residual effect than chemical fertilizers only. Amending chemical fertilizers with organic amendments can be used to ameliorate phosphorus fixation of acid soils to improve maize production on acid soils.  相似文献   
8.
Morphological traits and two kinds of molecular markers were employed to study the genetic relationships among improved rice (Oryza sativa ) varieties of Indonesia since 1943. Dendrograms based on morphological traits and both molecular markers (simple sequence repeats, SSR and single nucleotide polymorphism, SNP) agreed in separating the varieties into two primary groups. Based on the morphological traits, a larger group (>60 %) contains varieties with smaller sizes compared with those in the smaller group (<40 %). SSR and SNP markers revealed that most of the varieties belonged to indica (88; 89 %) and japonica (9; 8 %) subspecies, and 3 % of varieties were not involved in two subspecies. The molecular markers revealed that the genetic diversity (H) stagnated between stage II (1967–1985) and stage III (1986–2003). However, during stage I (1943–1966), H was higher than in the other stages as revealed by SNP markers, while H in stage I was lower than in the other stages as revealed by SSR markers. In this study, the two molecular data sets were positively correlated and positive correlations between the phenotypic and molecular data depended on the kind of molecular marker: SNP had higher Mantel r values than SSRs. Besides, SSR markers seem to be appropriate for pedigree studies, while SNP markers could be used to reveal genomic relationships. These findings were attributable to the different properties of these two different markers. These results suggested that the diversity and differentiation of both the phenotypic and molecular marker variations were probably resulted from the crossing and selection in rice breeding in Indonesia. We suggest that Indonesia needs another strategy to improve new varieties to avoid a reduction in genetic diversity and similarity.  相似文献   
9.
Analysis of the genetic structure of Indonesian Oryza sativa and O. rufipogon using neighbour-joining trees based on single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers revealed that O. sativa in Indonesia is separated from O. rufipogon. Accessions of O. sativa in this study were differentiated into two major groups, indica and tropical japonica, excluding some varieties. SSR and SNP markers revealed the high value of differentiation (F ST) and genetic distance (D) between indica and tropical japonica and we discovered four loci by SNP markers and one locus by SSR markers that play a role in differentiation between indica and tropical japonica. Interestingly, genetic diversity (H) in O. rufipogon was lower than that in O. sativa, however H in O. rufipogon was the highest and H in tropical japonica was the lowest when O. sativa was divided into two groups. Inbreeding coefficient (Fst) showed evidences that gene flow (Nm) between species and within species might be one of the mechanisms related to the diversification and differentiation of Indonesian rice germplasm by asymmetric pattern between species and within O. sativa as revealed by SSR and SNP markers. In addition, we found evidences on stabilizing selection in Indonesian rice germplasm and they might be the reasons why Indonesian rice germplasm did not differentiate due to source location of landrace. However, we found a weak relation between SSR and SNP markers probably due to highly polymorphic in SSR and the different properties of both markers.  相似文献   
10.
The marine leech, Zeylanicobdella arugamensis, is a major threat to aquaculture in grouper-producing countries including Indonesia. This study aimed at investigating prevalence, intensity and histopathology of the ectoparasite in humpback and hybrid groupers cultured in different rearing systems. A total of 260 groupers (60 humpback groupers and 200 hybrid groupers) were used for samples. The marine leech was observed on skin, fins, gills and mouth, followed by histopathological assay on the skin tissue. The results showed that prevalence of the leech in both groupers was higher when they were cultured in the floating net cages compared with the hatchery, p < .05. Furthermore, humpback grouper had a higher prevalence than hybrid grouper when they were cultured in a similar system, p < .05. Meanwhile, there was no significant difference in intensity between the two groupers, p > .05. Within the hybrid groupers, the highest prevalence was obtained from hybrid groupers reared in the earthen ponds. Histopathological studies showed that the infected groupers exhibited inflammation, congestion and erosion of the epidermis layer. Hybrid grouper had more severe histopathological lesions in the skin tissues. These results suggested that species and type of aquaculture system had significantly determined the prevalence, intensity and severity of lesion in Z. arugamensis infestation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号