Digital Commons Network^™

The Effect Of Environment And Cultural Practices On The Cold Hardiness Of Peach Wood, Larry A. Sagers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were conducted to better understand the effect of temperature, photoperiod, cultural practices, and growth regulators on the hardening and dehardening of peach tree wood.

Greenhouses were constructed to control temperatures to which peach trees were exposed. It was noted that hardening and dehardening usually followed the temperature fluctuation fairly closely. However, trees exposed to temperatures above 60 F (15.6 C) became hardy to 0 F (-17.8 C).

A photoperiodic response in regard to an increase or decrease in hardiness was not definitely observed in peach wood. Extended photoperiod did not produce any significant effect on hardiness. Defoliation, bloom date, …

Influence Of Environment And Cultural Practices On Rest, Cold Hardiness, And Abscisic Acid Concentration Of Gleason Elberta Peach Buds, Ronald H. Walser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of temperature, defoliation, light, and certain fall cultural practices on rest and hardiness of Gleason Elberta peach buds were studied. The influence of these factors on abscisic acid concentration in peach buds and a possible role of ABA in rest and hardiness of peach buds were also investigated.

Peach leaf buds enter rest in early fall, reach a rest intensity peak in early winter, then break rest as a chilling requirement is met. Complete defoliation before rest has begun will cause some leaf and flower buds to grow, while defoliation after rest has begun will not cause visible …

Seedling Rust Of Safflower -- Its Influence On The Performance Of Selected Varieties And Partial Hybrids, Jon James Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rust-infested and uninfested seedlots of 14 safflower (Carthamus tinctorius) entries (4 resistant lines, 4 moderately or fully susceptible lines, and six F₁ hybrids from crosses between rust-susceptible females and rust-resistant males), were planted in replicated field trials. The four infested entries resistant to seedling rust incited by Puccinia carthami Cda. exhibited average stand losses of 2.4, 8.4, 18.4, and 27.7%. Stand reduction in the resistant entries was not greater than the inherent compensating ability of the surviving plants; consequently, the yield of these entries was not significantly reduced. Plots from the rusted seedlots of the moderately and …

Factors Influencing Germination And Seedling Survival Of Several Varieties Of Astragalus Lentiginosus Dougl., Paul Ziemkiewicz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Astragalus lentiginosus, which consists of 36 varieties, is one of the principal locoweeds of western North America. The objectives of this study included identification of some of the major factors affecting germination of the seed and survival of the newly established seedlings for several of these varieties.

The seeds of the varieties studied exhibited two mechanisms for dormancy. One is a seed coat that is impermeable to water, and the other is a water-leachable inhibitor. The presence or absence of low-intensity incandescent light (in 14-hour day lengths) had no effect on germination. Of three temperature regimes studied, the regime …

Nutritional Quality And Herbage Production Of Intermediate Wheatgrass (Agropyron Intermedium [Host] Beauv.) When Infested With Black Grass Bugs (Labops Hesperius Uhler), Alan M. Gray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two intermediate wheatgrass seedings with different levels of grass bug infestation were evaluated for herbage production, seedhead production, percent dry matter, crude protein, and cell contents. Study sites were located at different elevations on mountain summer ranges in northern (Site I) and central (Site II) Utah. Study plots at Site I and Site II were infested with 113 and 210 bugs per sweep, respectively. Herbage production appeared to be reduced in early spring on the site with the higher infestation; however, no effect on season-long herbage production could be detected on either site. Seedhead production on infested plots was reduced …

Gas Exchange And Water Relations Of Two Alpine And Two Arctic Tundra Plant Species, Douglas Allan Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although water stress is an important selective force in many environments, it is not commonly considered to be of particular importance in tundra areas. Even though large portions of tundra may have an abundance of water, other more exposed areas may become quite dry. This microsite variability with respect to moisture stress was reflected in soil water potential measurements obtained from an alpine tundra area on Niwot Ridge in Colorado. Even though soil water potentials were consistently above -5 bars in a relatively low lying Deschampsia meadow, soil water potentials from an exposed fellfield area were often as low as …

The Use Of Foliar Applied Zinc Compounds In Correcting Zinc Deficiency In Fruit Crops, Lynn F. Hall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effectiveness of two chelated zinc compounds in correcting zinc deficiencies was studied. Soil and foliar treatments were made to study possible residual zinc carry-over from one season to the next. Foliar treatments at various rates were applied to raise plant tissue zinc levels above deficiency levels. It was found that none of the treatments studied resulted in any substantial carry-over of zinc to the following year. All of the foliar zinc treatments resulted in an increase in leaf zinc content in all of the varieties of fruit studied. The level of zinc in the treated trees increased in proportion …