STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS     

T. E. Williams  H. K. Baker 《Grass and Forage Science》1957,12(1):49-55

Various methods of root sampling are reviewed and discussed in relation to the type of information required. The root sampling techniques at the Grassland Research Institute are described and examples of sampling errors are given. Details of a root washing machine are given.  相似文献   

Introgression and stabilization oferwinia tuber soft rot resistance into potato after somatic hybridization ofsolanum tuberosum ands. brevidens     

J. Mitchell McGrath  Christie E. Williams  Geraldine T. Haberlach  Susan M. Wielgus  Thomas F. Uchytil  John P. Helgeson 《American Journal of Potato Research》2002,79(1):19-24

Resistance to potato tuber soft rot caused byErwinia carotovora was transferred fromSolanum brevidens to the cultivated potato over the course of four backcross generations originating from a somatic hybrid. Soft rot reactions were determined via a tuber plug inoculation method developed during the course of these experiments. Soft rot resistance was highest in the somatic hybrid (only ca. 20% of tubers and plugs showed evidence of severe rotting) and lowest among progeny of control potato x potato crosses (ca. 80% of tuber plugs showed severe rot). Backcross generations involving somatic hybrids were intermediate in their reaction, and resistance stabilized to about 60% of tuber plugs showing severe rot in the BC₂ through the BC₄. Reciprocal crosses showed no difference in the inheritance of soft rot resistance, indicating that neitherS. brevidens norS. tuberosum donor cytoplasm had a significant effect on the expression of resistance. Crosses between BC₃ siblings where noS. brevidens genetic markers were detected but resistance was segregating demonstrated a dosage effect for soft rot resistance. We conclude that introgression of soft rot resistance has occurred and that at least one locus responsible for resistance inS. brevidens now resides in theS. tuberosum genome.  相似文献   

Leaf mineral nutrient concentrations or media pH affect Georgia Jet sweetpotato transplant number,length, and weight 1     

J. M. Dangler  J. E. Brown  G. E. Boyhan  J. C. Williams 《Journal of plant nutrition》2013,36(7):1459-1469

The results of four experiments were combined to determine the relationships between leaf mineral nutrients or media pH and sweetpotato transplant production. The relative number of transplants and the relative mean transplant lengths or weights were determined by comparing the values obtained with unamended aged pine sawdust, a traditional medium. These values were regressed against leaf mineral concentrations and media pH. There was no relationship between relative transplant production and leaf nitrogen (N), potassium (K), or manganese (Mn) concentrations. Compared to sufficiency ranges for nearly mature sweetpotatoes, concentrations of N and K were low and Mn was sufficient. An upper value of 1210 mg/L leaf iron (Fe) was obtained for relative mean transplant weight, but concentrations of this mineral were not associated with relative transplant numbers or relative mean transplant lengths. Leaf calcium (Ca) and magnesium (Mg) concentrations were related to all three transplant characteristics directly, or indirectly through possible effects on leaf phosphorus (P) concentration or media pH. Compared to the established sufficiency ranges for nearly mature sweetpotato plants, Ca and Mg concentrations were low, P and Fe concentrations were sufficient, and zinc (Zn) concentrations were high.  相似文献   

Review of The Chinese Medicinal Herb Farm     

Debby Williams 《Journal Of Agricultural & Food Information》2013,14(1):87-88

Collaborative ventures between industry and professional association represent a strategy to maximize resources for a mutual goal. As a cooperative venture, The American Dietetic Association co-sponsored with Kraft General Foods, Inc. and The Good Housekeeping Institute a survey on American's diet and nutrition habits. The survey findings focused on consumer's behaviors, attitudes, knowledge and obstacles toward diet and nutrition. The results from the survey are being used to create and expand nutrition education campaings to the public.  相似文献   

An aboveground–belowground assessment of ecosystem properties associated with exotic annual brome invasion     

Caley K. Gasch  Stephen F. Enloe  Peter D. Stahl  Stephen E. Williams 《Biology and Fertility of Soils》2013,49(7):919-928

Exotic annual brome invasion has been well studied in western North American rangelands, particularly for Bromus tectorum L. invasion in sagebrush (Artemisia tridentata) grasslands. We examined both aboveground and belowground properties in native sagebrush grassland and adjacent areas dominated by exotic annual bromes (B. tectorum L. and Bromus japonicus Thunb.) to better understand the fundamental ecological differences between native and invaded areas. Field sites were located in north central Wyoming, USA, and plots were established in areas that had been historically subject to wildfire and either (1) recolonized by native sagebrush grassland vegetation or (2) invaded by exotic annual bromes. We employed measures of vegetation community structure as well as soil physical, chemical, and microbiological properties. Plots with greater than 20 % exotic annual brome cover had significantly less cover of all native vegetation functional groups resulting in lower richness and evenness than native plots. Invaded plots also had low diversity plant communities that were continuous and uniform across space. Soils beneath invaded plant communities had higher infiltration rates, higher levels of total nitrogen, and a lower C/N ratio than the native soils. Invaded soils also had 90–96 % lower abundance of all soil microbial groups measured by phospholipid fatty acid. We conclude that areas dominated by exotic annual bromes display different aboveground and belowground properties compared to the native community, and these changes possibly include spatial and temporal shifts in soil resources and organic matter processing.  相似文献   

Zinc nutrition affects alfalfa responses to water stress and excessive moisture     

Harsharn Singh Grewal  Rex Williams 《Journal of plant nutrition》2013,36(7):949-962

The interactive effect of applied zinc (Zn) and soil moisture on early vegetative growth of three alfalfa (lucerne) (Medicago sativa L.) varieties was investigated in a sand‐culture pot experiment to test whether there is link between Zn nutrition and soil moisture stress or excessive moisture tolerance in alfalfa plants. Three varieties (Sceptre, Pioneer L 69, and Hunterfield) with differential Zn efficiency (ability of a variety to grow and yield well in a Zn deficient soil is called a Zn‐efficient variety) were grown at two Zn levels (low Zn supply: 0.05 mg Zn kg^‐1 of soil, adequate Zn supply: 2.0 mg Zn kg^‐1 of soil) and three levels of soil moisture (soil moisture stress: 3% soil moisture on soil dry weight basis; adequate soil moisture: 12% soil moisture on soil dry weight basis; excessive soil moisture: 18% soil moisture on soil dry weight basis) in a Zn deficient (DTPA Zn: 0.06 mg kg^‐1 soil) siliceous sand. Zinc treatments were applied at planting, while soil moisture treatments were applied three weeks after planting and continued for two weeks. Plants were grown in pots under controlled temperature conditions (20°C, 12 h day length; 15°C, 12 h night cycle) in a glasshouse. Plants grown at low Zn supply developed Zn deficiency symptoms, and there was a severe solute leakage from the leaves of Zn‐deficient plants. Adequate Zn supply significantly enhanced the leaf area, leaf to stem ratio, biomass production of shoots, and roots, succulence of plants and Zn concentration in leaves. At low Zn supply, soil moisture stress and excessive moisture treatments significantly depressed the shoot dry matter, leaf area and leaf to stem ratio of alfalfa plants, while there was little impact of soil moisture treatments when supplied Zn concentration was high. The detrimental effects of soil moisture stress and excessive soil moisture under low Zn supply were less pronounced in Sceptre, a Zn‐efficient alfalfa variety compared with Hunterfield, a Zn‐inefficient variety. Results suggest that the ability of alfalfa plants to cope with water stress and excessive soil moisture during early vegetative stage was enhanced with adequate Zn nutrition.  相似文献   

Can spinosad be effective for the integrated management of Anastrepha ludens (Tephritidae) in soil and fallen fruit,and be compatible with the parasitoid Diachasmimorpha longicaudata (Braconidae)?     

Williams  Trevor  Mercado  Gabriel  Aluja  Martín 《Phytoparasitica》2021,49(1):73-82

Phytoparasitica - Tephritid fruit flies are susceptible to insecticide treatments when leaving infested fruit to pupate in the soil and when emerging as adults. Laboratory experiments involved...  相似文献   

An Evaluation of Rabies Vaccination Rates among Canines and Felines Involved in Biting Incidents within the Wellington–Dufferin–Guelph Public Health Department     

K. Bottoms  L. Trotz‐Williams  S. Hutchison  J. MacLeod  J. Dixon  O. Berke  Z. Poljak 《Zoonoses and public health》2014,61(7):499-508

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The transmissible spongiform encephalopathies: disease risks for North America.     

Elizabeth S Williams 《Veterinary Clinics of North America: Food Animal Practice》2002,18(3):461-473

Transmissible spongiform encephalopathies exotic to North America (BSE and associated diseases) are unlikely to be introduced or to persist should they be introduced into the United States [2]. Domestic TSEs (scrapie, CWD, and TME) seem to be relatively restricted in their host range, and none of these diseases is known to naturally cause disease in cattle. It is important that surveillance for TSEs continues, however, particularly in cattle because of the extreme consequences to the livestock industries, and potentially, public health, if BSE becomes established. Because the TSEs have implications beyond effects on their natural host species, adequate surveillance, control, and even eradication of these diseases should be goals for the livestock industries, wildlife managers, and animal health agencies in the United States.  相似文献   

Comparison of digital image analysis using elliptic Fourier descriptors and major dimensions to phenotype seed shape in hexaploid wheat (Triticum aestivum L.)     

Keith Williams  Jesse Munkvold  Mark Sorrells 《Euphytica》2013,190(1):99-116

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