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41.
Summary Experiments were performed to study the effects of the ethylene releasing compound Ethrel on sex expression in cucumbers and squash, and of Alar (B-995) plus Ethrel in muskmelons. As a result of foliage sprays with one or both of the above compounds normally monoecious plants produced female flowers only, for the first 2–3 weeks of flowering. The optimum treatments for cucumbers were two foliage sprays with Ethrel 250 ppm or 500 ppm applied at the second and the fourth true leaf stages. The optimum treatments for squash were Ethrel 250 ppm and 500 ppm applied at the first and the third true leaf stages.High doses (1000 ppm) or repeated applications of Ethrel retarded growth of muskmelons and cucumbers. Applications of B-995 (5000 ppm) plus Ethrel (500 ppm) at the second true leaf stage inhibited male flowering for 2–3 weeks of the flowering period. F1-hybrid seeds of muskmelons were experimentally produced in large isolation cages in the field, using two monoecious lines as female parents. The merits and some of the problems associated with the production of F1-hybrid seeds by the above methods are discussed. 相似文献
42.
Tika B. Adhikari Ramchandra Basnyat 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(3):303-305
Twenty strains of Xanthomonas campestris pv. campestris (Xcc) were isolated from two major crucifer-growing valleys, Chitwan and Kathmandu in Nepal and characterized by biochemical and pathogenicity tests. Strains were homogeneous in bacteriological characteristics. The ability of a strain to induce high or low disease severity index (DSI) on three host plants, broccoli, cabbage, and cauliflower, was interpreted as virulence. Strains that were associated with high or low virulence were significantly different (P>0.05). No relationship between virulence and biochemical characteristics was observed. 相似文献
43.
Adhikari Sneha Kumari Jyoti Jacob Sherry Rachel Prasad Pramod Gangwar O. P. Lata Charu Thakur Rajnikant Singh Amit Kumar Bansal Ruchi Kumar Sundeep Bhardwaj S. C. Kumar Subodh 《Genetic Resources and Crop Evolution》2022,69(2):499-523
Genetic Resources and Crop Evolution - Agricultural production is facing serious threat from various biotic and abiotic stresses specifically under climatic challenges. It is becoming increasingly... 相似文献
44.
Forest fragmentation and regrowth in an institutional mosaic of community, government and private ownership in Nepal 总被引:1,自引:0,他引:1
Harini Nagendra Sajid Pareeth Bhawna Sharma Charles M. Schweik Keshav R. Adhikari 《Landscape Ecology》2008,23(1):41-54
This study analyzes forest change in an area of Nepal that signifies a delicate balance between sustaining the needs and livelihood
of a sizable human population dependent on forest products, and an effort to protect important wildlife and other natural
resources. The study area, a portion of the Chitwan valley district of Nepal, represents what may be becoming a common institutional
mosaic in many countries of the world who have a population reliant on forest products for their livelihood: (1) a national
park; (2) a designated park buffer involving participatory forest management programs; (3) scattered patches of designated
community forest; and (4) large areas of adjacent landscape made up of mostly private landholdings under agricultural practices.
Utilizing Landsat images from 1989 and 2000, we analyze land cover change in each of these management zones using landscape
ecology metrics and quantifying proportional distributions of land cover categories. Our results show significant differences
in terms of land cover dynamics and landscape spatial pattern between these land ownership classes. These findings indicate
that community-based institutions (participatory management programs in the park buffer and the designated community forests)
are capable of halting or even reversing trends in deforestation and forest fragmentation. 相似文献
45.
Stagonospora nodorum blotch (SNB), caused by Phaeosphaeria nodorum, is a destructive disease of wheat (Triticum aestivum) found throughout the United States. Host resistance is the only economically feasible option for managing the disease; however, few SNB-resistant wheat cultivars are known to exist. In this study, we report findings from an association mapping (AM) of resistance to P. nodorum in 567 spring wheat landraces of diverse geographic origin. The accessions were evaluated for seedling resistance to P. nodorum in a greenhouse. Phenotypic data and 625 polymorphic diversity array technology (DArT) markers have been used for linkage disequilibrium (LD) and association analyses. The results showed that seven DArT markers on five chromosomes (2D, 3B, 5B, 6A, and 7A) were significantly associated with resistance to P. nodorum. Genetic regions on 2D, 3B, and 5B correspond to previously mapped quantitative trait loci (QTL) conferring resistance to P. nodorum whereas the remaining QTL appeared to be novel. These results demonstrate that the use of AM is an effective method for identifying new genomic regions associated with resistance to P. nodorum in spring wheat landraces. Additionally, the novel resistance found in this study could be useful in wheat breeding aimed at controlling SNB. 相似文献
46.
AIM: To investigate the role of free-living animals such as spar- rows, rodents and flies as potential reservoirs of Campylobacter spp on a dairy farm, and to assess the genetic diversity among Campylobacter isolates from the farm and an urban source. METHODS: A total of 290 samples (bovine, passerine and ro- dent faeces, and whole flies) were collected from a large com- mercial dairy farm in the Manawatu district in New Zealand, and from faeces from urban sparrows in a nearby city. Other samples collected from the dairy farm included five from silage, two from aprons worn by workers during milking, two from workers' boots and two from water in troughs in a paddock. Isolates of thermophilic Campylobacter spp were identified mor- phologically and phenotypically and further characterised mo- lecularly using pulsed-field gel electrophoresis (PFGE) and the restriction enzyme SmaI. RESULTS: Campylobacter jejuni was the only Campylobacter species isolated from all samples. The highest prevalence was found in faeces from dairy cows (54%), followed by faeces from sparrows from the urban area (40%) and the farm (38%), and from rodents (11%) and whole flies (9%). Other samples from the farm environment such as silage, trough water, and work- ers' aprons and boots were also positive for C. jejuni. Of the 22 restriction patterns obtained, seven were common to more than one source. CONCLUSIONS: Cattle, sparrows, rodents and flies are po- tential reservoirs of C. jejuni on dairy farms. Identical clones of C. jejuni carried by cattle, sparrows, flies and rodents prob- ably indicate a common source of infection. The high level of asymptomatic carriage of C. jejuni by healthy dairy cows could be sufficient to maintain infections within the dairy farm sur- roundings via environmental contamination. 相似文献
47.
S. Kundu Tapan Adhikari S. Rajendiran J. K. Saha A. Subba Rao 《Journal of plant nutrition》2016,39(13):1971-1978
A study was conducted with maize in Vertisol, Inceptisol, Alfisol and Aridisol to evaluate the efficacy of the pine oleoresin coated urea fertilizers (coated with 1.25, 2.50, 3.75 and 5.00% pine oleoresin). Significant increase in biomass yield was observed in all the soils when urea was coated with pine oleoresin at 3.75% or more. All the pine oleoresin coated urea in Inceptisol and Aridisol; and 3.75% and 5% pine oleoresin coated urea in Vertisol and Alfisol significantly increased nitrogen (N) uptake as compared to uncoated urea. Nitrogen use efficiency increased from 19.34% to 32.80% in Vertisol, 13.06% to 28.27% in Alfisol, 13.87% to 23.86% in Inceptisol and 10.68% to 20.23% in Aridisol, as a result of coating urea with pine oleoresin. Thus the results indicate that there is a beneficial effect of coating urea with pine oleoresin with respect to yield, N uptake and use efficiency in maize crop. 相似文献
48.
Upadhaya Krishna Barik Saroj Kanta Adhikari Dibyendu Baishya Ratul Lakadong Nigyal John 《林业研究》2009,20(3)
在5个典型自然种群Mylliem(种群1)、Upper Shillong(种群2)、Shillong Peak(种群3)、Laitkor(种群4)和Nongpiyur(种群5)中,详细研究了冬青树(Ilex khasiana)种群结构和再生生态学,旨在探究种群结构和再生能力的影响因素.在全光照(100%),中等光照(50%)和低光照(30%)三种光强度条件下,实验观察表明:在中等和低光照条件下的种苗成活率和生长状态好于在高光照条件下的种苗成活率和生长状态.成年树种群(≥5cm dbh)的密度直径分布揭示了一种再生种群的典型特征.对植被的破坏和人类其他干扰导致森林树冠疏开使光照增强,造成自然种群(L khasiana)幼苗的高死亡率.本研究结果对制定适当的物种保护措施有重要价值. 相似文献
49.
I U Grün K Adhikari C Li Y Li B Lin J Zhang L N Fernando 《Journal of agricultural and food chemistry》2001,49(6):2839-2843
Profiles of genistein, daidzein, genistin, daidzin, and their acetyl- and malonyl-beta-glycosides were determined in tofu as affected by temperature and time. Tofu was heated in water at 80, 90, and 100 degrees C for 0 (control), 10, 20, 30, and 40 min, and the contents of the isoflavones of interest were quantified using reversed-phase HPLC. Total isoflavone content decreased most likely due to leaching of isoflavones into the water. Because the content of the isoflavones of the genistein series was little affected by the treatments, the decrease in the total isoflavone content was almost exclusively due to a decrease of the daidzein series. Changes in the profile of the daidzein series suggest little decarboxylation of the malonylglycoside to the acetylglycoside, but considerable de-esterification of the malonyl- and acetylglycoside to the beta-glucoside. Strongly temperature dependent decreases of the aglycon suggest possible thermal degradation of daidzein in addition to losses due to leaching. 相似文献
50.
Absorption of protein, fatty acids and minerals in young turkeys under heat and cold stress 总被引:2,自引:0,他引:2
1. Absorption of protein, fatty acids, calcium, phosphate and potassium by young turkeys maintained at thermoneutral (24 degrees C), hot (35 degrees C) and cold (8 degrees C) conditions was examined. 2. Non-acclimatised, heat-stressed birds absorbed less potassium and phosphate, whereas absorption of nitrogen, fatty acids and calcium was not altered, as compared with birds at 24 degrees C. Non-acclimatised, cold-stressed birds absorbed less calcium than control birds and more nitrogen than non-acclimatised, heat-stressed birds. 3. Heat acclimatization might reduce the adverse effect of heat stress on potassium and phosphate absorption. 相似文献