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Agricultural Science

Series

1999

Articles 31 - 38 of 38

Full-Text Articles in Life Sciences

The Reproductive Biology And Effective Pollinators Of The Endangered Beardtongue Penstemon Penlandii (Scrophulariaceae), Vincent J. Tepedino, Sedonia D. Sipes, Terry L. Griswold Jan 1999

The Reproductive Biology And Effective Pollinators Of The Endangered Beardtongue Penstemon Penlandii (Scrophulariaceae), Vincent J. Tepedino, Sedonia D. Sipes, Terry L. Griswold

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Penland's beardtongue, a rare endemic plant of the Colorado Plateau, displays a mixed breeding system. Plants are partially self-compatible but set more fruits when cross-pollinated than when self-pollinated. Fruit production is significantly increased by pollinators. However, in two years of study there was no indication that fruit set was being limited by inadequate pollinator visitation. Pollinator effectiveness was judged by correlating bee behavior at the flowers with analysis of the pollen carried on bee bodies. The most important pollinators were native megachilid bees, particularly in the genus Osmia. The bees that pollinate Penland's beardtongue are essential to its reproduction …

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Economic And Environmental Benefits Of Soil/Water Nitrogen Testing: The Case Of Central Nebraska, C. S. Kim, Harold Taylor, Carmen Sandretto Jan 1999

Economic And Environmental Benefits Of Soil/Water Nitrogen Testing: The Case Of Central Nebraska, C. S. Kim, Harold Taylor, Carmen Sandretto

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

This research presents a competitive dynamic model to evaluate the economic and groundwater quality benefits resulting from the adoption of soil/water nitrogen testing. The model is applied to an irrigated corn production county in the Nebraska Mid-State area where the groundwater contamination level from nitrates is reported to be, on average 18.7 parts per million (ppm). Adoption of nutrient management practices would result in increased economic benefits to farmers and reduced nitrate stocks in groundwater.

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Analysis Of Human Skin Emanations By Gas Chromatography/Mass Spectrometry. 1. Thermal Desorption Of Attractants For The Yellow Fever Mosquito (Aedes Aegypti) From Handled Glass Beads, Ulrich R. Bernier, Matthew M. Booth, Richard A. Yost Jan 1999

Analysis Of Human Skin Emanations By Gas Chromatography/Mass Spectrometry. 1. Thermal Desorption Of Attractants For The Yellow Fever Mosquito (Aedes Aegypti) From Handled Glass Beads, Ulrich R. Bernier, Matthew M. Booth, Richard A. Yost

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Handled glass has the ability to collect and concentrate nonaqueous human skin emanations while minimizing the collection of aqueous perspiration. Compounds originating from the skin and collected on glass have previously been found to attract the Aedes aegypti species of mosquito. Therefore, glass beads were used as the medium to collect skin emanations from humans for subsequent chemical analysis. This process consisted of a 5-15-min collection of sample on glass beads, followed by loading the beads into a gas chromatograph (GC) injector insert for subsequent desorption of the collected compounds onto the GC column. After cryofocusing by liquid nitrogen at …

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Report Of The Berry Working Group (Strawberry, Raspberry/Blackberry, Blueberry), Erin Rosskopf Jan 1999

Report Of The Berry Working Group (Strawberry, Raspberry/Blackberry, Blueberry), Erin Rosskopf

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Strawberries are a relatively recently domesticated crop. The most commonly cultivated strawberry, Fragaria x ananassa, is a hybrid of the North American F. virginiana and the South American F. chiloensis (Maas 1998). These parental species are still grown in some areas and F. virginiana is the primary wild, sexually compatible relative to the cultivated strawberry. In addition to F. virginiana, F. vesca and its subspecies are also present in the United States. Fragaria x ananassa and F. virginiana readily cross. Introgression of pest resistance traits into the wild strawberry population is likely, as substantial amounts of crop-weed introgression …

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Notes: Evaluation Of A Filter Bag System For Ndf, Adf, And Ivdmd Forage Analysis, Kenneth P. Vogel, Jeffrey F. Pedersen, Steven D. Masterson, John J. Toy Jan 1999

Notes: Evaluation Of A Filter Bag System For Ndf, Adf, And Ivdmd Forage Analysis, Kenneth P. Vogel, Jeffrey F. Pedersen, Steven D. Masterson, John J. Toy

Department of Agronomy and Horticulture: Faculty Publications

A new method of determining in vitro dry matter digestibility (IVDMD) as recently developed in which the digestion is conducted with the forage samples in filter bags. Our objective was to compare the filter bag and conventional IVDMD analysis methods using smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.), and forage sorghum [Sorghum bicolor (L.) Moench] samples. In addition, the filter bag analysis systems for determining non-sequential neutral and acid detergent fiber (NDF and ADF), respectively, were compared with the non-sequential conventional analysis systems. In the filter bag systems, the forage samples are sealed in filter bags and the …

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Measurement Of Sorghum Stalk Strength Using The Missouri-Modified Electronic Rind Penetrometer, Jeffrey F. Pedersen, J. J. Toy Jan 1999

Measurement Of Sorghum Stalk Strength Using The Missouri-Modified Electronic Rind Penetrometer, Jeffrey F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

Resistance to lodging is critical in sorghum [Sorghum bicolor (L.) Moench] grown for grain, yet adequate tools for plant breeders to assess this character at or before anthesis have not been developed. The objective of this study was to evaluate whether an electronic penetrometer previously shown to be an effective tool for measuring stalk strength in maize (Zea mays L.) could be usedd to differentiate among grain sorghum hybrids. Entries in three commercial grain sorghum hybrid trials were evaluated for rind penetrometer resistance (RPR) of the peduncle, the lower stalk anthesis and the lower stalk at maturity. Actual …

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Effect Of Leaf Phosphorus And Potassium Concentration On Chlorophyll Meter Reading In Rice, Shaobing Peng, Arnel L. Sanico, Felipe V. Garcia, Rebecca C. Laza, Romeo M. Visperas, Josue P. Descalsota, Kenneth G. Cassman Jan 1999

Effect Of Leaf Phosphorus And Potassium Concentration On Chlorophyll Meter Reading In Rice, Shaobing Peng, Arnel L. Sanico, Felipe V. Garcia, Rebecca C. Laza, Romeo M. Visperas, Josue P. Descalsota, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Chlorophyll meter (SPAD) is a convenient tool to estimate leaf nitrogen (N) concentration of rice plants. There is no information on the effects of leaf phosphorus (P) and potassium (K) concentration on SP AD readings and on the relationship between SPAD values and leaf N concentration in the literature. In 1996 dry season, cv IR72 was grown at the International Rice Research Institute (IRRI) and the Philippine Rice Research Institute (PhilRice) under various N, P and K fertilizer combinations. SPAD measurements were made on the topmost fully expanded leaves at mid-tillering and panicle initiation. The leaves were then detached, dried …

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Loci Controlling Resistance To High Plains Virus And Wheat Streak Mosaic Virus In A B73 × Mo17 Population Of Maize, A. Marçon, S. M. Kaeppler, S. G. Jensen, L. Senior, C. Stuber Jan 1999

Loci Controlling Resistance To High Plains Virus And Wheat Streak Mosaic Virus In A B73 × Mo17 Population Of Maize, A. Marçon, S. M. Kaeppler, S. G. Jensen, L. Senior, C. Stuber

Department of Agronomy and Horticulture: Faculty Publications

High Plains disease has the potential to cause significant yield loss in susceptible corn (Zea mays L.) and wheat (Triticum aestivum L.) genotypes, especially in the central and western USA. The primary causal agent, High Plains virus (HPV), is vectored by wheat curl mite (WCM; Aceria tossicheila Keifer), which is also the vector of wheat streak mosaic virus (WSMV). In general, the two diseases occur together as a mixed infection in the field. The objective of this research was to characterize the inheritance of HPV and WSMV resistance using B73 (resistant to HPV and WSMV) × Mo17 (moderately …

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