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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.
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.
Horticulture students in an entry-level course (plant propagation) and an upper-level course (small fruit crop production) were assigned brief lecture-based writing tasks at the end of each class period. For the first 5 minutes of each subsequent class period, students divided into small groups to discuss their 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 the lecture was resumed. Students collected their task responses in a workbook that they turned in for experimental evaluation at the end of the quarter. When compared to previous and concurrent sections of the same courses, students engaging in the writing tasks more frequently posed questions in class, posed questions of increased complexity, and demonstrated improved ability to perform well on complex exam questions requiring integration and synthesis of information.
`Honeycrisp', a relatively new apple cultivar, is susceptible to bitter pit, a physiological disorder that develops mainly during storage. Although the cause of bitter pit is unknown, calcium (Ca) content of the fruit is known to be involved. A field experiment was conducted in Chanhassen, Minn. to refine recommendations for use of Ca sprays for reduction of bitter pit in `Honeycrisp' apple. Specific objectives were to determine: 1) Ca concentration and content throughout the fruit growing season; and 2) the association of bitter pit incidence with Ca concentration, crop load, vegetative growth and fruit size. Six treatments tested included: control; Ca(NO3)2 sprays all season; Ca(NO3)2 sprays early in the season; Ca(NO3)2 sprays late in the season; hand-thinning combined with Ca(NO3)2 sprays all season and hand-thinning. Ca concentration in fruits was measured bi-weekly using three different sampling methods: segments, cores and plugs. A randomized block design with four trees as experimental unit and five replications was used. Results suggest lower crop loads increase bitter pit incidence. While fruit from the thinned treatments was larger in size by the end of the experiment, no bitter pit was present at harvest. After 4 months of storage, the hand thinning treatment had 7.4% bitter pit, while thinning plus Ca reduced bitter pit to 2.4%. The other treatments had less than 1% bitter pit. Fruit analyses at the end of the growing season indicate that early and full season sprays resulted in the highest Ca concentration in fruit segments and cores. The lowest values were found for the thinning treatment. No association was found between vegetative growth and bitter pit incidence.
In Fall 1999, the Univ. of Minnesota implemented a writing intensive requirement for undergraduates. As part of the requirement, students must take one writing intensive (WI) course in their major. Formal and informal writing in critical draft review are key components of intensive writing. The Dept. of Horticultural Science offers an Environmental Horticulture Major which currently has only one writing intensive course in its curriculum. Teaching faculty (13/14), responsible for 21 courses in the curriculum, were interviewed and syllabi were reviewed to gather information on what types of writing are currently being assigned and to discuss where WI courses should be placed in the Environmental Horticulture curriculum in the future. The majority of classes utilize formal writing and the majority of faculty review, or are willing to review, a draft of an assignment. Informal writing assignments are less common, indicating a deficient area of the curriculum. With slight modifications, many classes in the curriculum can meet the requirements to become WI. Faculty agreed that WI courses should be placed in upper level, smaller classes that place less emphasize on production techniques or plant identification.
Experiments were initiated to document the effect of cultivar, GA4+7, and number of fruit/spur on appendage number and flower bud initiation in apple. `Pacific Rose' is strongly biennial, `Braeburn' and `Fuji' are moderately biennial, and `Royal Gala' is not biennial. In the cultivar study, buds were sampled every 18 days starting at 50 days after full bloom and continuing through until leaf fall to determine the rate of appendage formation and appendage number in relation to doming. Because of the tendency for `Pacific Rose' to exhibit biennial bearing, the rate of appendage formation and the timing of doming were compared on nonfruiting trees, trees carrying a commercial crop, and trees sprayed with 300 PPM GA4+7 applied 14 days after full bloom. Number of appendages for the treatments were similar up to 100 days after full bloom. Presence of fruit on a spur has been demonstrated to inhibit flowering of apple. Spurs of `Pacific Rose', `Splendor', and `Royal Gala' were labeled with zero, one, two, and three fruit per spur and sampled three times during the season. As buds were harvested to count appendage number, the number of fruit per spur and the number of total seeds per spur were recorded. Correlation between number of seeds per spur and rate of appendage formation were done.
Lack of effective weed control is the major limiting factor in strawberry production. With few herbicides labeled for use in this perennial crop, weeds are controlled using manual labor, cultivation, and one or two herbicide applications. However, these practices do not provide long-term, effective weed control, and weeds continue to be the number one reason why strawberry fields are removed from production due to a reduction in yield. The objective of this study was to evaluate weed control during strawberry plant establishment using woven woolen mats and spring-sown canola. The effects of these mulches on weed control and strawberry plant production were studied independently and in tandem. Weed and daughter plant counts were compared among treatments to test for differences. Wool mulch, both single- and two-ply, was an effective barrier to weeds within the strawberry rows. Planting canola between rows or broadcasting in combination with the wool mulch decreased the number of weeds when compared to other treatments. The four treatments that included wool had the highest number of rooted daughter plants when compared to all the other treatments except the weed-free plot. The canola treatments without wool mulch did not produce as many rooted daughter plants and were not statistically different from the weedy-check.
Abstract
A nondestructive measurement technique for predicting the developmental stage of young embryos was devised and used to study developmental patterns of 2 Phaseolus crosses. While selfed P. coccineus Lam. produces normal seeds, P. coccineus × P. vulgaris L. aborts embryos when the seeds reach 10 mm in length. Seed growth of the interspecific cross was reduced with respect to days after pollination. Other characteristics of the interspecific cross included reduced pod length, an increased (pod length)/(number seeds per pod) ratio, reduced embryo fresh weight, and an increased volume of liquid endosperm. Between the self and the cross, pod thickness did not differ, and thus can be used to predict developmental stage of young embryos.
In Fall 1999, the University of Minnesota implemented a writing-intensive (WI) requirement for undergraduates. As part of the requirement, students must take one upper-division WI course in their major. As of Spring 2002, the environmental horticulture major through the Department of Horticultural Science had only one WI course in its entire curriculum. Teaching faculty were interviewed and syllabi were reviewed to gather information on what types of writing are currently being assigned and to discuss where more WI courses should be placed in the environmental horticulture curriculum in the future. These surveys and interviews revealed that the majority of classes require formal writing and that the majority of the faculty review or are willing to review a draft of an assignment, two key components of the WI requirement. Informal writing assignments are less common, indicating a deficient area of the curriculum. With slight modifications, many classes in the environmental horticulture curriculum can meet the requirements to become designated as WI. Faculty agreed that WI courses should be placed in upper-level, smaller classes that place less emphasis on production techniques or plant identification.
Abstract
Selection criteria to identify primocane-fruiting red raspberry seedlings (Rubus idaeus L.) with high, early yield are desirable in regions with short growing seasons. To identify possible parents contributing these desirable characteristics, ‘Heritage’, ‘Redwing’, and two genotypes from the Minnesota breeding program were subjected to yield component analysis. In all genotypes, yield was determined by canes/meter of row, fruit per node, and fruit weight. Over the 3-year period, ‘Heritage’ had the highest yield/meter of row, yield per cane, fruit per cane, and number of fruit per fruiting node among all genotypes. Component compensation was highest for ‘Redwing’, while MN 652 had the greatest degree of independence among components. In selecting seedlings for early fruiting and high yield, high cane densities and/or large fruit size will be needed.