Life Sciences Commons^™

Effects Of Leaflet Orientation And Root Morphology On Physiological Traits And Yield In Soybeans., Richard Dewayne Johnson

Doctoral Dissertations

Drought is the most important abiotic stress adversely affecting soybean (Glycine max (L.) Merr.) yield. Leaflet orientation has been shown to reduce leaflet temperatures and transpiration while root morphology has been related to slower wilting phenotypes. The objective of this study was to investigate effects of leaflet orientation and rooting morphology on whole plant transpiration, yield, water use efficiency, and other physiological traits in soybeans using grafting techniques, population lines, near-isogenic lines, and restrained leaf canopy experiments. Experiments were conducted in Knoxville, TN with additional yield trial plots at Springfield, Spring Hill, and Milan, TN. Data were collected on …

Using The Ceres-Maize Model To Create A Geographically Explicit Grid Based Estimate Of Corn Yield Under Climate Change Scenarios, Ryan Zachary Johnston

Graduate Theses and Dissertations

The CERES-Maize model was evaluated in its capacity to predict both regional maize yield and water use within the United States Department of Agriculture (USDA) Economic Research Service (ERS) Region 1 between the years 1997-2007. A grid based, geospatially explicit method was developed to express the various rainfed and irrigated maize cultivars grown across the region. Overall, the calibrated model compared well for both physiological and yield parameters, producing significant linear relationships (p

The calibrated and validated CERES-Maize model was used to predict potential evapotranspiration and yield under three IPCC weather scenarios for the year 2050 to evaluate crop production …

Heritability And Genetic Gain Of Seed Protein, Oil, And Yield Among Ril Of Soybean, Benjamin T. Wiggins

Masters Theses

Soybean is a remarkable crop that is used in many aspects of our everyday lives. The seed protein is used primarily for livestock feed, though it is becoming more available as a meat substitute for human consumption. Soybean oil is used in many products such as plastics, foods, and industrial products. Seed yield is the major trait that is selected for in a breeding program. A population of 239 F₄ derived RIL from the cross of USG 5601T × U99-310255 was used to calculate heritability estimates by parent offspring regression and on an entry mean basis. This population was …

The Effect Of Salinity Level Upon The Yield, Root Growth, And Water Extraction Of Contrasting Rooting Subpopulations Of Alfalfa (Medicago Sativa) Under Conditions Of Zero Leaching, Laura A. Vincent

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A major problem in irrigated agriculture in the Western U.S. is the gradual accumulation of salinity in the plant root zone. These nonuniformly saline soils contain increasing amounts of salinity with depth, and salt accumulation is accelerated in situations where leaching is minimized. Root growth and thus plant yield is limited in these soils due to decreased water uptake. We studied the root growth of two subpopulations of alfalfa differing in their ability to produce fibrous roots to determine if altering root morphology would increase plant yield and water extraction, in an irrigated saline soil.

Soil profiles for a control …

Influences Of Nitrogen Supply And Elevated Co2 On Nitrogen Consumption, Nitrogen Loss, Tissue Nitrogen Concentration, And Yield Of Hydroponic Wheat, Karl B. Ritchie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat was grown hydroponically for 23 days (early boot stage) in a controlled environment at NO₃^- concentrations of 100 and 1000 μmol and CO₂ levels of 360 and 1200 μmol mo1^-1. Nitrogen consumption and transpiration were measured daily. Tissue nitrogen concentration, total biomass, and percent root mass were measured at harvest. Nitrogen recovery and nitrogen use efficiency were calculated. Elevated CO₂ increased nitrogen consumption of the 100 μmol NO₃^- treatment by 13.6% and the 1000 μmol NO₃^- treatment by 21.3%. These increases were particularly evident during …

Forage Yield And Chemical Composition Of An Orchardgrass-Bromegrass Pasture Mixture As Influenced By Clipping Frequency, Nitrogen Fertilization And Irrigation Regime, Vinayak G. Gawai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The influence of agronomic practices on forage production and chemical composition of an orchardgrass-bromegrass pasture mixture was studied at the Greenville Farm, Logan, Utah, during 1960-1964. The soil is a well drained Millville Silt loam that has about a one percent slope and occurs on an alluvial fan. It is high in potash, phosphorus and calcium and is alkaline having a pH of 7.9 to 8.2.

Analysis of the clipping frequency showed that the yield of forage from four harvests was greater than from five harvests. This difference was greater on plots receiving high rates of nitrogen fertilization, and frequent …

General And Specific Combining Ability Of Five Alfalfa Clones Including Reciprocal Effects For Seedling Vigor And Seed Yield, Edwin Theodore Bingham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The use of F₁ hybrids for commercial production of such cross-pollinated crops as corn, sorghum, sugar beets, onions, and pearl millet suggests the feasibility of using this technique for alfalfa. Production of F₁ hybrids of commercial value is dependent on the use of breeding material expressing good combining ability. In order to obtain precise estimates of combining ability for quantitative characters in alfalfa, it is necessary to produce all possible single crosses among a number of parents. The single cross seed required is difficult to obtain due to the vegetative reproduction and isolation required; and, subsequently, limited testing …

Seasonal Yield And Nitrogen Content Of Three Grasses Grown Alone And In Association With Each Other And With White Dutch Clover, Donald B. Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The chief aim of pasture research is to discover means of providing the largest possible amount of highly nutritious forage at the time the animal requires it. Throughout the grazing season animal herbage requirements are relatively constant, while herbage production from pastures usually is quite variable.

The Influence Of Time And Rate Of Application Of Urea Spray On The Yield And Protein Content Of Winter Wheat, Vern L. Marble

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Winter wheat, with an annual average acreage of about 300,000 acres, forms an integral part of the farm economy of Utah.

For many years intermountain agronomists and farmers alike have known dry-land wheat production to be limited by low summer rainfall. In the past 15 years, however, it has become apparent through intelligent research that in many cases lack of nitrogen has been the limiting factor. When this occurs, winter wheat production can be increased by correcting this nitrogen deficiency

The Yield, Quality, And Nutrient Relationships Of Celery As Affected By Commercial Fertilizer, Rex L. Hurst

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Celery production has become an important factor in the economy of certain areas in Utah. In 1949 over 400 acres were harvested with an average yield of 800 crates per acre, the average return per crate being $1.80. this amounts to over half a million dollars. The crop serves as a valuable cash crop, creates a demand for hand labor, and serves as an important commercial fertilizer.

The Effect Of Time, Quantity, And Kind Of Irrigation On The Yield Of Sugar Beets, Delos Boyd Archibald

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigations on factors affecting yield of sugar beets during the past two years at Newton and Garland, Utah, have shown two outstanding facts about irrigating sugar beets. First, the amount of water applied may not be as important as the time at which they receive it. Second, sugar beets should not be made to suffer for water in the early part of their growing season.

These observations suggest the need for further studies on method, time and quantity of irrigation. Further information on the most economical use of irrigation water for sugar beets would be of great value to the …

The Effects Of Fertilizer And Moisture On The Yield Of Sweet Corn, Rex F. Nielson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sweet corn is rapidly becoming an important cash crop in many of the irrigated regions of the intermountain West. The lacome from this crop is relatively small in comparison to that from other major agricultural products; however, sweet corn production has a definite place in the economy of the region.

One of the factors limiting increasing acreage of sweet corn in many areas is low yields. Yields have been increased naterially in recent years with the development of hybrid varieties, superior to the standard varieties previously used. Better cultural practices are improving yields, but much remains to be done in …