Digital Commons Network^™

Ecophysiological Analysis Of Yield Determination In Soybean Of Different Relative Maturities, Maria Morrogh Bernard

Theses and Dissertations--Plant and Soil Sciences

Soybean yield differences are a combination of the genotype, environmental conditions, and management practices. Understanding how these factors interact through the analysis of the components involved in yield determination, provides a way to increase potential and actual yields in Kentucky.

Two irrigated experiments were conducted to quantify differences in the mechanisms of yield determination across soybean maturity groups (MG) 2 to 5 (Chapter 1), and to quantify management options (seeding rate and choice of MG cultivar) that increase yield potential of double crop soybean systems (Chapter 2).

Results showed that cultivars used different physiological strategies to achieve high yields, but …

Genetic And Functional Analysis Of Host Genes Involved In Pathogenic And Symbiotic Legume-Microbe Interactions, Fang Tang

Theses and Dissertations--Plant and Soil Sciences

Legumes form symbiotic and pathogenic interactions with microbes. Understanding the molecular mechanisms underlying the legume-microbe interactions would help us to improve crop production in a sustainable manner. This thesis covers two independent research projects. The first project was to study the role of alternative splicing in RCT1-mediated disease resistance. RCT1 is a TIR-NBS-LRR-type plant resistance (R) gene in Medicago truncatula that confers broad-spectrum resistance to Colletotrichum trifolii, a fungal pathogen that causes anthracnose disease in Medicago. RCT1 undergoes alternative splicing at both coding and 3'-untranslated regions, thereby producing multiple transcript variants in its expression profile. …

Evaluation Of Input-Intensive Soybean Management Systems And The Effect Of Lactofen Application On Soybean Physiology, John M. Orlowski

Theses and Dissertations--Plant and Soil Sciences

In an effort to maximize yields, many soybean growers have begun moving to intensive, input-based soybean management systems. However, limited reliable information exists about the effect of these inputs on soybean yield. The purpose of this study was to evaluate the effect of individual inputs and combinations of inputs as part of high-yield management systems on soybean seed yield and to determine the effect of one of these inputs, lactofen, on soybean physiology. Small plot studies were established in nine states across the Midwest. A number of commercially available soybean inputs were evaluated individually and in combination to determine their …

Corn And Soybean Profitability 2010, Gregory S. Halich

Agricultural Economics Presentations

No abstract provided.

Early Maturing Varieties And Soybean Cyst Nematodes: Will This Marriage Work?, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Soybean cyst nematode (SCN) is widely distributed in Kentucky’s soybean growing areas. The use of SCN-resistant varieties has long been a recommended production practice for infested fields. However, continuous use of such varieties can result in a shift to a race of SCN which is able to vigorously attack previously resistant varieties. For this reason, many states recommend that producers periodically grow a crop of SCN-susceptible soybeans within a crop rotation when SCN populations are at minimal levels (causing less than a 5% loss in yield). The UK Plant Pathology Department recommends a four year rotation in SCN-infested fields [PPA3; …

Preliminary Maturity Group Ii Soybean Variety Trials, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

On-farm research with early maturing soybean varieties in Kentucky in both 1993 and 1994 has indicated that Maturity Group (MG) II varieties yield competitively with our traditional MG IV varieties. In those tests, four MG II varieties were compared with a single, high yielding MG IV variety (Asgrow A4715) over a range of planting dates on a total of 27 farms across both years. Asgrow A4715 averaged 43 bu/A, while the best MG II variety (Jack) averaged 39 bu/A. Such on-farm strip tests are valuable for comparing varieties under true production conditions. However, strip tests can effectively compare only a …

Early Maturing Varieties And Soybean Cyst Nematodes: Will This "Marriage" Work?, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Soybean cyst nematode (SCN) is widely distributed in Kentucky's soybean growing areas. The use of SCN-resistant varieties has long been a recommended production practice for infested fields. However, continuous use of such varieties can result in a shift to a race of SCN which is able to vigorously attack previously resistant varieties. For his reason, many states have long recommended that producers periodically grow a crop of SCN-susceptible soybeans within a crop rotation when SCN populations are too low to cause yield reductions. In Kentucky, the UK Plant Pathology Department recommends a four year rotation in SCN-infested fields [PPA3; "Wanted: …

An Evaluation Of Twelve Maturity Group Ii Soybean Varieties At Lexington, Kentucky, Larry J. Grabau, Colleen C. Steele

Agronomy Notes

In both 1993 and 1994, the Kentucky Soybean Promotion Board funded an on-farm test of a small set of Maturity Group (MG) II varieties. Those studies showed that several MG II varieties were competitive with a high-yielding MG IV variety. However, other MG II varieties did not perform as well in those tests, indicating that variety selection is an important management consideration if this early maturing cropping system is to be successful in Kentucky soybean producers' fields. MG II varieties used in past University of Kentucky tests have been chosen based on their performance in university variety trials where such …

Grain Quality Of Early Maturing Soybean Grown In Kentucky, M. V. Kane, Colleen C. Steele, Larry J. Grabau, C. T. Mackown, David F. Hildebrand

Agronomy Notes

Interest in grain quality of US soybean has grown in recent years. For example, in 1990, there was much interest in "component pricing" of soybean grain, Under that plan, growers would be paid a price for their grain that reflected the value of the protein and oil it actually contained, rather than the common price paid to all growers, regardless of any variation in protein and oil content. However, the soybean processing industry is evidently not excited about the complexity of testing individual lots for protein and oil and keeping track of pricing structures depending on those results. As a …

Growth Of Early Maturing Soybean, M. V. Kane, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Production of early maturing soybean varieties has grown in popularity across the southeastern US in recent years. Many growers in Mississippi, Arkansas, and Texas have seen this system as a way to avoid late season drought. However, several Kentucky growers have had good success with the use of Maturity Group (MG) II soybeans in the recent seasons which had generally good rainfall patterns. Some growers are glad to get competitive yields from MGII soybean while gaining the opportunity to harvest some of their soybean acreage before corn is ready to harvest.

On-Farm Testing Of Early Maturing Soybean, Colleen C. Steele, Larry J. Grabau, N. Gift

Agronomy Notes

Maturity Group (MG) II soybean varieties have performed well in University of Kentucky tests over the past several years. Early planted (late April/early May) tests in the relatively dry years of l986 through 1989 showed MG II yields to exceed those of MG III or MG lV. Over the generally wetter years 1990 through 1993, MG III and lV yields were slightly better than those of MG II varieties. Across eight years of data, MG II yield averages were virtually identical to those of MG III and lV. Perhaps growers could plant a portion of their soybean acreage to MG …

Planting Dates For Early Maturing Soybean, M. V. Kane, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Early maturing soybean cropping systems have been gaining in popularity with producers across the southeastern US, as well as in Kentucky. To our south, some producers in Texas, Arkansas, and Mississippi are using varieties that are two or three Maturity Groups (MG) earlier than those traditionally grown. The main intent in those states has been to avoid late summer drought by using early maturing varieties coupled with early planting. Previous Kentucky research in this area has also emphasized early planting(late April). However, a number of Kentucky growers have had good success using later planting dates for early maturing varieties, particularly …

An Evaluation Of Twelve Maturity Group Ii Soybean Varieties At Lexington, Kentucky, Larry J. Grabau, Colleen C. Steele

Agronomy Notes

In 1993, an on-farm study funded. by the Kentucky Soybean Promotion Board showed that the best Maturity Group (MG) II variety tested was quite competitive with the best available MG IV variety. However, other MG II varieties did not fare as well, indicating that careful variety selection will be essential for on-farm success with this MG II cropping system. MG II varieties used in past University of Kentucky tests have been chosen based on their performance in university variety trials where they are normally grown, for example, in Iowa, Illinois, Indiana, and Ohio. Such tests include relatively large numbers of …

Reduced Scepter Rates For Broadleaf Weed Control In Soybean, D. S. Jones, H. Lin, M. V. Kane, Larry J. Grabau

Agronomy Notes

Public agencies are placing greater scrutiny on herbicide applications by farmers. For example, the corn herbicide atrazine is now classified as a restricted use pesticide, with limits placed on allowable rates. While soybean growers may share some of this concern for the environment, rate reduction is more likely to be attractive for economic reasons. Some growers are already cutting back on herbicide rates. For example, Missouri data shows that the average application rates for soybean herbicides were only 75% of the labelled rate. While reduced rates might save growers money, and may be kinder to the environment, there is a …

Growing Soybean Varieties From Multiple Maturity Groups Can Reduce Yearly Yield Volatility, Todd W. Pfeiffer

Agronomy Notes

In the Kentucky Soybean Performance Test program, varieties of maturity groups (MG) 3, 4 and 5 are tested to provide information on their relative yields. The difference in maturity between the earliest and the latest maturing variety in the test in any year is approximately 30 days. In general, although some regional differences appear, the long-term state-wide and within region yield of the different maturity groups (average yield of a 11 varieties in a maturity group) is equal (Table 1). As I've inspected results from the Kentucky Soybean Performance Tests for the last decade, it appeared that some of the …

An Early-Planted, Early Maturing Soybean Cropping System: Yield And Harvest Losses, Larry J. Grabau, M. V. Kane, H. Lin, Dennis B. Egli

Agronomy Notes

Most soybean varieties used In Kentucky, whether grown full season or double-cropped behind wheat or barley, are from Maturity Groups (MG) IV or V. Some MG III varieties are also grown; however, virtually no MG 1/ or earner varieties are planted. Agronomists and soybean producers in Kentucky· have generally felt that MG IV and V varieties produce the highest yield. Since the driest months in Kentucky are August, September,and October, MG IV and V varieties frequently encounter moisture stress during the important seed fill stage. The use of earlier maturing varieties was initially proposed as a means of getting a …

Does Chemical Leaf Burn Of Double Crop Soybeans Reduce Yield?, Larry J. Grabau, Todd W. Pfeiffer, S. Nevins

Agronomy Notes

Most farmers who have applied acifluorfen (sold as Blazer or Tackle) for postemergence control of broadleaf weeds in soybean fields are aware that leaf crinkling, bronzing, and necrosis can result. Despite this, studies in Kentucky, Illinois, Arkansas, and South Carolina have shown that full season soybeans have plenty of time to recover from leaf burn caused by this herbicide, and no yield losses have been found. However, double crop soybeans are usually planted much later than the full season crop. This delay in planting may reduce the time for plants to complete vegetative growth before beginning the seed production process. …

Using Performance Test Results In Soybean Variety Selection In Kentucky, Todd W. Pfeiffer

Agronomy Notes

Many soybean varieties are available to, soybean producers in Kentucky each year. Information is available from company advertisements, private yield tests, and public performance tests which producers can use when selecting a variety. The question arises as to how this information relates to variety performance on a particular farm. The value of yield test data lies in the predictive ability of that data. How well does data from a set of environments predict relative performance among varieties over the wide range of possible environments in which those varieties can be grown? The first objective of this note is to discuss …

Grain Sorghum And Soybean Variety Tests On Reconstructed Prime Land - 1985, R. I. Barnhisel, Morris J. Bitzer, William O. Thom

Agronomy Notes

Prime farmland disturbed by surface mining must by law be returned to a productivity level equal to that before mining. The coal operator has several test crops that can be selected to determine whether these production standards have been met before final bond release will be made. Grain sorghum and soybeans are two of the crops that may be used. The purposes of this research are (1) to determine the crop yield potential of restored prime farmland from surface mined areas, (2) to determine varietal adaptation on restored prime farmland as compared to non-mined prime farmland, and (3) to provide …

Response Of Soybean Cultivars To Postemergence Herbicides, James R. Martin, W. W. Witt

Agronomy Notes

The acreage of soybeans treated with postemergence herbicides for broadleaf weed control has increased over the past few years. This trend has occurred because of inconsistent control of cocklebur (Xanthium pensylvanicum Wallr), giant ragweed (Ambrosia trifida L.), jimsonweed (Datura stramonium L.), and morningglory (Ipomoea hederacea (L.) Jacq. and Ipomoea purpurea (L.) Roth) with soil applied herbicides.

Soybean Inoculant Quality, J. L. Sims, E. C. Lacefield, Lloyd W. Murdock

Agronomy Notes

Research studies have shown that from 40 to 80 percent of the nitrogen required for a soybean crop comes from nitrogen fixed in the nodules, depending on the degree of nodulation and the level of soil nitrogen. Hence, it is important that soybean plants be well-nodulated for most efficient soybean production.

Soybean Seed Quality Survey, Dennis M. Tekrony

Agronomy Notes

During the past four years soybean acreage has nearly tripled in Kentucky to 1.1 million acres in 1973. Even though the total acreage has increased substantially, the average yield per acre has declined slightly during the same period to 28 bushels per acre in 1973. Why this low statewide average yield when we know that some Kentucky farmers consistently produce yields of over 40 bushels per acre? Many factors can contribute to this problem including; improper use of herbicides and pesticides, inadequate soil fertility, non-adapted varieties, low quality planting seed, and timely management of all production practices. The objective of …

The Influence Of Soil Temperature On Soybean Seed Emergence, Dennis B. Egli, J. L. Hatfield, J. Hill, Dennis M. Tekrony

Agronomy Notes

The best way to obtain adequate soybean stands is to plant high quality seed in an optimum soil environment. But this year many farmers may not be able to obtain enough high quality soybean seed and some acreage may be planted with seed of lower than normal quality. Thus it will be even more important to have an optimum soil environment.

Preliminary Report, Soybean Performance Tests - 1971, Dennis B. Egli

Agronomy Notes

The data presented below represent the preliminary results of the 1971 Soybean Performance Tests. A more complete version of the data, including data from previous years, will be published at a later date in "Results of the Kentucky Soybean Performance Tests - 1971."

York Soybeans Added To Recommended List, Dennis B. Egli

Agronomy Notes

York soybean, a pure line selection developed by the Virginia Agricultural Experiment Station from a cross of Dorman X Hood, was recently added to the recommended list for Kentucky. It was released jointly in 1967 by Virginia, Maryland, and North Carolina.

Preliminary Report Soybean Performance Tests 1970, Dennis B. Egli

Agronomy Notes

The data presented below represent the preliminary results of the 1970 Soybean Performance Tests . A more complete version of the data, including data from previous years , will be published at a later date in "Results of the Kentucky Soybean Performance Tests - 1970."

Notice Of Release Of Custer Soybean, J. F. Shane, S. H. Phillips

Agronomy Notes

The Crops Research Division, Agricultural Research Service, and the cooperators listed above announce the release of a new phytophthora and cyst nematode-resistant soybean variety named Custer. Custer is the second cyst nematode-resistant variety to be released. It is earlier than the previously released variety Pickett.

New Soybean Varieties, J. F. Shane, S. H. Phillips

Agronomy Notes

Several new soybean varieties have been released during the past few months. Many have appeared in the Uniform Soybean Nurseries at Henderson or Fulton as number strains or named varieties. The following abbreviated descriptions may be of help in comparing these newer releases with more widely known material.