An economic evaluation of total confinement, partial confinement, and pasture swine production systems

Cover title

Genetic manipulation of tall fescue

Genetic manipulation of tall fescue (Festuca arnndinacea Schreb.) has not been altered by the discovery of the Acremonium coenophialum (Morgan-Jones and Gams) / grass interaction. However, tall fescue breeding programs have been affected greatly. The basic methods for genetically manipulating the grass have remained static. Tall fescue is an obligate out-crossing species, and most improvements are, therefore, captured in the form of an improved population developed through some form of mass or recurrent selection. What has changed is the breeder\u27s ability to recognize genetic differences in the grass because of the confounding effect of A. coenophialum on plant phenotype. It is, therefore, critical that breeders recognize A. coenophialum status in their plants prior to selection. The other major change in tall fescue breeding since the discovery of the A. coenophialum/grass interaction is a tremendous increase in breeding activity

Genetic manipulation of tall fescue

Genetic manipulation of tall fescue (Festuca arnndinacea Schreb.) has not been altered by the discovery of the Acremonium coenophialum (Morgan-Jones and Gams) / grass interaction. However, tall fescue breeding programs have been affected greatly. The basic methods for genetically manipulating the grass have remained static. Tall fescue is an obligate out-crossing species, and most improvements are, therefore, captured in the form of an improved population developed through some form of mass or recurrent selection. What has changed is the breeder\u27s ability to recognize genetic differences in the grass because of the confounding effect of A. coenophialum on plant phenotype. It is, therefore, critical that breeders recognize A. coenophialum status in their plants prior to selection. The other major change in tall fescue breeding since the discovery of the A. coenophialum/grass interaction is a tremendous increase in breeding activity

ALTERATION OF PLANTS VIA GENETICS AND PLANT BREEDING

Plant breeding is man-directed evolution. Plant breeders manipulate the genetic resources of a species, i.e., its germplasm, to produce plants that are of increased value to humanity. The same analogy applies to animal improvement programs. All of our major food crops and all of our domestic animals and their respective breeds, strains, or cultivars were developed by this process. Although humans have successfully manipulated the genetic resources of plants and animals for several thousand years, the science of genetics and breeding was not developed until this century

Considerations in Breeding Endophyte-Free Tall Fescue Forage Cultivars

Breeding tall fescue (Festuca arundinacea Schreb.) cultivars that are free of the endophytic fungus Acremonium coenophialum Morgan-Jones and Gams [previously identified and referred to as Epichloe typhina (Fries) Tulasne] is necessary to improve animal performance. The techniques used in developing new cultivars are not greatly different from those used previously, with one exception. Prior to the evaluation of new tall fescue lines or populations, the endophyte needs to be eliminated from the seed or the plants. Several techniques utilizing aging, heat, or chemical treatment are being used to effectively accomplish this in the seed. Methods for permanently eliminating the endophyte from plants are not available. The major new considerations in breeding endophyte-free tall fescue cultivars do not involve drastic changes in breeding methodology, but rather focus on new objectives. In the past, much effort was directed at overcoming the toxic effects of the endophyte. Now, breeders can focus their efforts on objectives such as increasing digestibility, physiological efficiency, mineral uptake, and insect and disease resistance. Losses in stress tolerance due to the elimination of the endophyte from tall fescue may also have to be addressed, especially in areas of marginal adaptation

Considerations in Breeding Endophyte-Free Tall Fescue Forage Cultivars

Breeding tall fescue (Festuca arundinacea Schreb.) cultivars that are free of the endophytic fungus Acremonium coenophialum Morgan-Jones and Gams [previously identified and referred to as Epichloe typhina (Fries) Tulasne] is necessary to improve animal performance. The techniques used in developing new cultivars are not greatly different from those used previously, with one exception. Prior to the evaluation of new tall fescue lines or populations, the endophyte needs to be eliminated from the seed or the plants. Several techniques utilizing aging, heat, or chemical treatment are being used to effectively accomplish this in the seed. Methods for permanently eliminating the endophyte from plants are not available. The major new considerations in breeding endophyte-free tall fescue cultivars do not involve drastic changes in breeding methodology, but rather focus on new objectives. In the past, much effort was directed at overcoming the toxic effects of the endophyte. Now, breeders can focus their efforts on objectives such as increasing digestibility, physiological efficiency, mineral uptake, and insect and disease resistance. Losses in stress tolerance due to the elimination of the endophyte from tall fescue may also have to be addressed, especially in areas of marginal adaptation

Degrading sludge with cellulase complex

The ability of indigenous and commercial cellulase complexes to degrade native and pretreated sludge was evaluated. Indigenous enzyme was produced in our laboratory, where as commercial cellulase was purchased from a chemical supplier. Pretreatments included detergent solutions, sodium hydroxide, hydrochloric acid, sulfuric acid, sulfur trioxide, alkaline peroxide and sonification. Glucose production was used to infer degradability. Compared controls (no glucose produced), hydrochloric acid and sodium hydroxide treatment resulted in most degradation. Other treatments were much less effective. The commercial cellulase degraded standards (cellulose) much more rapidly and extensively than indigenous. Although commercial cellulase and either sodium hydroxide or hydrochloric acid treatment increased degradability of sludge considerably above the controls, improvement was much less than expected. Physical appearance of sludges was altered greatly by pretreatment but the implications of this are unclear.Project # G-1572-06 Agreement # 14-08-0001-G-157

The Enigma of Genetic Linkage in Molecular Breeding for Maize

University of Minnesota Ph.D. dissertation.June 2017. Major: Applied Plant Sciences. Advisor: Rex Bernardo. 1 computer file (PDF); vii, 67 pages.Linkage among quantitative trait loci prevents the release of hidden genetic variation, but also preserves desirable gene combinations. This dissertation, which includes three studies, shows the continuing enigma of linkage in maize (Zea mays L.) breeding. The first study aimed to determine if the additional recombinations in doubled haploids induced from F2 instead of F1 plants leads to a larger genetic variance and a superior mean of the best lines. In two maize populations, inducing doubled haploids from F2 plants did not improve the mean, and it increased the genetic variance for moisture, but not for yield and plant height. The second study aimed to determine if multi-allelic markers or haplotypes improve the prediction accuracy of genomewide selection in three-way breeding populations, which could have three alleles per locus. In both simulated and empirical maize populations, accounting for multiple alleles did not improve the prediction accuracy over a biallelic model. The third study aimed to determine if genomewide markers can be used to partition trait effects into independent and correlated portions, and if selection on the independent portion was more effective than selection on the entire trait. Results from four cycles of selection showed that selection only for the independent portion did not lead to higher responses for yield, moisture, and plant height. Overall, genetic linkage both assists and confounds molecular breeding efforts in maize

The fescue fungus problem

"Tall fescue has been widely accepted as a forage plant. It is particularly well adapted to the southern portion of the cornbelt where it has been planted on millions of acres of pasture lands."--First page.H.N. Wheaton and D.A. Sleper (Department of Agronomy) and Einar Palm (Department of Pathology, College of Agriculture)New 10/84/20

Myoglobin properties of electrically stimulated bovine longissimus muscle

Typescript (photocopy)