The objective of our study was to establish first year strawberry plantings without using herbicides. `Honeyoye' transplants were set into plots measuring 6.1m × 7.32m on 21 May, 1993. Four treatments were established: winter wheat, a dwarf Brassica sp., napropamide (2.24kg/h), and no weed management. After the strawberry plants, cover crops (and some weeds) were fairly well established, (18 June) 6 week-old African “weeder” geese were put into half of each plot to graze. Weekly data was taken on the percentage of soil area covered with plant material, height and stage of development of plants, and weeds present. A weed transect was done in 6 July. Plant material was collected from each plot on 26 July and 16 Sept. in a 0.2m2 area, and dried. The most promising cover crop treatment was the dwarf Brassica for early season weed control. However, the herbicide treatment with no geese produced the best strawberry plant growth.
Charlotte Herman and Emily Hoover
Emily Hoover and Doug Foulk
Decision cases have been written for use in horticulture education for some time at the Univ. of Minnesota. How faculty involve graduate students in this process will be discussed using the decision case Sunny Hollow Orchard. This decision case concerns the need to make management decisions in a commercial apple orchard planted largely with Haralson, a russet-susceptible cultivar. The growers involved had to decide whether the application of GA4+7 for russet suppression was appropriate for their operation, given all the factors which required addressing. The case was written for use in fruit production or other intermediate-to-advanced undergraduate course. The case can be used to illustrate the decision-making processes involved in operating a commercial crop production enterprise encompassing such issues as cultural and environmental factors, financial viability and pesticide concerns. The case exposes students to a real-life situation and provides them with the opportunity to face a complex but not uncommon situation for producers in the horticultural industry. We will then focus on how this case fit into the entire PhD research program and how we hope to integrate this kind of experience into graduate education.
Tim Kenny and Emily Hoover
The Minnesota Landscape Arboretum has been educating urban youth in a garden setting through the Children's Garden in Residence program located in Minneapolis, Minn., for 20 years. The program partners with community groups to teach pre-K to 4th grade students about the wonders of science and nature. The program presently educates between 100 and 120 children each summer. In addition to serving more children, the program curriculum and activities have evolved through the years, developing, trying, redesigning, and trying again curricula to meet the needs of urban children. The result of this process is a program that emphasizes hands-on, garden-based lessons in science, nutrition, and art. We are in the process of documenting the curricula used in the program. This paper will discuss the history of the program, highlight a few units used at the different grade levels, and discuss the documentation process.
Anne Fennell and Emily Hoover
The grape species Vitis labruscana Bailey and V. riparia Michx. were subjected to a decreasing photoperiod at constant moderate temperatures to determine whether acclimation occurred in response to a shortening photoperiod. Cane growth, periderm development, killing temperature of the primary bud, and bud dormancy were measured in vines receiving a natural photoperiod (ND), a simulated long photoperiod of 15 hours (LD), and shorter photoperiods of 14, 13, or 12 hours (SD). The LD treatment was effective at maintaining growth and inhibiting periderm development and the onset of bud dormancy in V. labruscana. Cane growth rate with all SD treatments decreased as compared to the LD regime. A significant increase in periderm development occurred with the 12-hour SD treatment. Similarly, the onset of bud dormancy was promoted by the 12-hour SD in V. labruscana. The primary bud killing temperature was 1C lower in V. labruscana under the 12-hour SD than under the LD treatment. In contrast, the LD treatment neither maintained growth nor fully inhibited periderm development and the onset of dormancy in V. riparia. The decrease in the cane growth rate upon exposure to SD was significantly greater in V. riparia than V. labruscana. Periderm development was observed in both the SD and its respective LD-treated V. riparia vines. However, the rate of periderm development was significantly greater in the SD vines than in the LD vines. The onset of bud dormancy was promoted by 13-hour SD in V. riparia. Similarly, the primary bud killing temperature was 2 to 3C lower in V. riparia upon exposure to SD. Vitis riparia has a longer critical photoperiod than V. labruscana and appears to be more sensitive to changes in light intensity or light quality. While the change in freezing tolerance in response to short photoperiods is small, the photoperiod response at a longer critical photoperiod, when combined with lower temperatures, will promote an earlier and possibly more rapid cold acclimation in V. riparia than in V. labruscana.
Jean M. Larson and Emily Hoover
Formative evaluation (pretesting) can lead to better working exhibits in public gardens. While many botanical gardens and arboreta will attest to the importance of using formative evaluation, it has not been used to develop exhibits for consumers with diverse disabilities. At the Clotilde Irvine Sensory Garden of the University of Minnesota Landscape Arboretum (Chanhassen, Minn.) we are interested in developing exhibits that meet the needs of audiences with disabilities. To that end in 2000, four comprehensive interpretive exhibits were pretested before the final exhibits were installed within the Clotilde Irvine Sensory Garden to determine the exhibits ability to teach concepts to all regardless of disability. The evaluation indicated these exhibits were physically accessible, but needed attention in specific areas to enhance their inclusiveness.
Marjorie E. Ross* and Emily E. Hoover
Cultivar may cause variation in arbuscular mycorrhizal fungi (AMF) colonization levels leading to differences in shoot growth and runner formation, and in pathogen control in strawberries. However, a clear consensus has not been reached regarding the degree to which cultivar affects the formation of the symbiosis or its functioning. The study was conducted on four commercial strawberry farms in Minnesota and Wisconsin to compare, within a farm, mycorrhizal colonization and plant response among three strawberry cultivars: `Winona', `Anapolis' and `Jewel'. At each farm, two 6 × 6 meter plots of each cultivar were randomly selected. On each of three sampling dates, 4 whole plants and soil samples were collected from these plots in the 2003 field season. Roots were separated from shoots and leaves, and fresh and dry weights were taken. Leaves and soil were dried, weighed, and submitted for nutrient analysis. Soil nutrient analyses include phosphorus (Bray P), potassium, pH, buffer pH and organic matter. Leaf tissue analyses include P, K, Ca, Mg, Na, AL Fe, MN Zn, Cu, B, Pb, Ni, Cr, and Cd. Roots were collected, frozen, and prepared for scoring using methods adapted from Koske and Gemma (1989). Presence of mycorrhizal colonization is being scored using the methods of McGongle et al. (1990). Levels of mycorrhizal colonization among different strawberry cultivars will be compared. We will also use biomass measurements, to determine mycorrhizal effects on plant growth among different cultivars. Soil and leaf analysis data will be used to determine effects of AMF on plant nutrition and compare effects among cultivars.
Adriana Telias, Emily Hoover, and Diego Rother
One of the most important factors determining apple (Malus pumila P. Mill.) market acceptance is peel color. Coloring of ‘Honeycrisp’ fruits can adopt two patterns: blushed or striped. This is an unusual phenomenon in apple. The objective of this study was to compare ‘Honeycrisp’ fruit from trees that were propagated from buds occurring on branches carrying only blushed or striped fruit. We concluded that blushed trees tend to produce a higher percentage of blushed fruit than striped trees, indicating a mechanism conserved through cell division. The percentage of blushed fruit on any given tree changed from year to year. Blushed and striped fruit occurred together on the same branch, and even on the same spur, with fruits located in the outer canopy being more likely to be striped. Higher crop loads were associated with a lower percentage of blushed fruit on the tree. Blushed and striped fruit do not consistently differ in their maximum pigment accumulation before ripening. The comparison of average hue angle for the whole peel at harvest indicates that blushed fruit are redder on average. Stripes were caused by reduced anthocyanin accumulation in certain portions of the peel and not by deeper localization. We speculate that an epigenetic mechanism regulates the pattern of anthocyanin accumulation in ‘Honeycrisp’ apple. Increased production of blushed, redder apples may be achieved through clonal selection and crop load regulation. A software tool for efficient relative color evaluations was developed and is freely available to the community.
Doug S. Foulk and Emily E. Hoover
Horticulture students in an entry-level course (Plant Propagation) and an upper-level course (Small Fruit Crop Production) were assigned brief writing tasks at the end of each class period based upon that day's lecture. Student writing was intended to be expressive in nature, i.e., for the author's use only. For the first five minutes of each class period, students divided into small groups to discuss possible responses to the previous day's task and to generate questions related to the task topic. The class then reconvened as a whole for a question-and-answer session before lecture was resumed. Students collected their writings in a workbook which they turned in for experimental evaluation only at the end of the quarter. When compared to previous and concurrent sections of the same courses, students engaging in the writing tasks asked more numerous and thoughtful questions in class and demonstrated increased ability to perform well on complex exam questions requiring integration and synthesis of information.
Doug S. Foulk and Emily E. Hoover
`Haralson,' the most widely-grown cultivar in Minnesota, is highly susceptible to russetting and cracking in many orchards. Because wax platelet arrangement has been proposed as a cause for russettting in `Golden Delicious' apples, we examined the wax platelet arrangement of `Haralson' apples. When compared to the wax platelet arrangement found on the russet-susceptible `Golden Delicious,' and on `McIntosh,' a cultivar which does not russet in our region, `Haralson' platelets were large and upright in orientation, more numerous than found on `Golden Delicious,' but unlike the smaller, more granular platelets found on `McIntosh.' In a concurrent study, we made four GA,,, (Provide) applications, at petal fall and at p.f. +10, 20, and 30 days. At harvest, the treated and untreated blocks of trees were examined for incidence of russet, 25-ct. wt., and total yield per tree. Treated trees produced a greater number of fruit of slightly larger size and with reduced incidence of russet than untreated trees in the study.
Emily Hoover, Doug Foulk, and David Davis
Decision cases are designed to enhance students critical thinking by engaging them in authentic problem situations. Students are assigned the role as decision maker with a dilemma to solve. In the assignment, the decision maker has to weigh the issues, identify the options, and develop strategies for solutions either individually or as a group. The authors have been writing and using decision cases in upper level undergraduate production courses in fruits and vegetables to integrate information from classes in plant pathology, entomology, and production horticulture. Decision cases dealing with weed control strategies in small fruit production and vegetable production scheduling will be discussed to illustrate the strengths and weaknesses of the case approach.