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Leaf removal has been reported to be beneficial to fruit quality of several grape cultivars. However, climatic conditions, time of leaf removal and genotype have a strong influence on the effect of leaf removal on fruit quality traits, such as soluble solids and titratable acidity. The effect of leaf removal on fruit quality of two vinifera grape cultivar grown in Minnesota was examined in this study. The first six basal leaves were removed from four canes on each vine of `Riesling' and `Chardonnay'. Leaf removal was carried out at two different times after the onset of verasion--early August (8/2) and late August (8/23). Fruit was harvested in late September and yield and fruit quality data were recorded. The results of the 1989 study will be discussed here. Leaf removal did not significantly affect yields obtained from either cultivar, regardless of leaf removal date. Early leaf removal on `Chardonnay' vines resulted in significantly higher soluble solids and significantly lower titratable acidity than that observed for fruit of control or late removal treated vines. Similar results were observed for `Riesling', however the differences were not significant. Data from 1989 and 1990 will he presented and discussed in the talk.
Minnesota has a long history of strong citizen involvement in environmental, community development, economic development, and human rights issues. Therefore, it is not surprising there are many individuals, organizations, communities, and educational institutions in Minnesota actively involved in the sustainable agriculture debate. The challenge we face is how to help these strong forces work in collaboration to solve rural problem s.
In 1990 representatives of five community-based organizations and the U of M agreed to form the Minnesota Institute for Sustainable Agriculture (MISA) to be housed at the University and governed by a board of community and University representatives. The purpose of MISA is to bring farmers and other sustainable agriculture community interests together with University administrators, educators, researchers, and students in a cooperative effort to undertake innovative, agenda-setting programs that might not otherwise be pursued in the state.
We evaluated the extent to which `Swenson Red' seeded grape (Vitis × spp.) responded to single and repeated GA3 applications to induce seedless fruit development. Field studies were conducted to test the time of pre-anthesis GA3 application (18, or 24 May or 3 June), the usefulness of postanthesis application, the optimum GA3 concentration (0, 0.075, 0.15, or 0.3 mm), and the method of application. The treatment dates that gave a high percentage of seedless berries with an acceptable berry count per cluster were 24 May with postanthesis application and 3 June pre-anthesis only. The optimum GA3 concentration was 0.15 mm applied both before and after anthesis. The most seedless berries developed when pre- and postanthesis applications were used, indicating many seedless fruit developed from flowers that would have abscised. There was no difference in percent heedlessness, number of berries per cluster, or number of seeds per berry between clusters dipped or sprayed with 0.3 mm GA3. Chemical uame used: gibberellic acid (GA3).
Focus groups and surveys were used to align volunteers' work with the mission and organizational objectives of the Minnesota Landscape Arboretum (MLA) at the University of Minnesota. In focus groups, a cross-section of volunteers discussed several issues, including how they could more directly contribute to the mission and organizational objectives of the institution. Staff were surveyed on their perceptions of the volunteer workforce, including their current use of volunteers. Focus groups and surveys proved to be valuable tools to approach programmatic changes in volunteer involvement at the MLA by providing a platform to discuss the areas where change is needed, as well as what kind of change should occur. Focus groups can be a key tool in involving volunteers, by allowing them to provide input on changes that directly affect them, in addition to furthering the understanding of volunteer needs and motivations.
Consumer demand for local and organic strawberries (Fragaria ×ananassa) is increasing. Growers who can meet this demand have a competitive edge in the direct-to-consumer market. Innovations in strawberry production for northern climates offer new opportunities for growers to meet the demand for local organic strawberries. Typically adopted for season extension, the use of poly-covered tunnels for crop protection provides other benefits including protection from adverse weather. Low tunnels are easy to install, low cost, temporary protective structures that are well-adapted for annual day-neutral strawberry production, and they are more space efficient than high tunnels for these low-stature crops. A range of specialty tunnel plastics that modify and diffuse light are available, but there is little information on how these influence strawberry plant growth and performance in the field. Our objectives were to determine the effects of experimental ultraviolet blocking and transmitting plastics on light and microclimate in low tunnel environments and assess differences in fruit yield and quality in the day-neutral strawberry cultivar Albion in an organic production system. This research was conducted on U.S. Department of Agriculture-certified organic land over 2 years, in 2016 and 2017. We found that ultraviolet intensity and daily light integral (DLI) were lower in covered plots than in the open field. Maximum daily temperatures were slightly higher in covered plots. Both ultraviolet-blocking and ultraviolet-transmitting plastics improved marketable fruit yield compared with the open-field control. Strawberries grown in the open-field treatment were lower in chroma than covered plots in 2017, and there was no difference in total soluble solids between treatments in either year. Low tunnel systems allow for increased environmental control and improved fruit quality and are well-adapted for day-neutral organic strawberry production systems.
Application of calcium (Ca) sprays is a recommended practice to reduce the incidence of Ca-related disorders such as bitter pit in apple (Malus ×domestica), but effectiveness of sprays to increase Ca concentrations in the fruit is not always consistent. Strontium (Sr) has been used as a Ca analog to evaluate Ca transport processes and distribution in plants. A field study was conducted using foliar- and fruit-applied Sr as a tracer for Ca transport in 20-year-old `Honeycrisp' apple trees on Malling.26 (M.26) rootstock. The objectives of this study were to 1) measure the amount of Sr translocation from leaves to fruit, 2) determine the effectiveness of eight sprays applied over the growing season vs. four late-season sprays on increasing Sr concentrations in leaves and fruit, and 3) evaluate the effect of an experimental adjuvant consisting of alkyl-polysaccharides and monosaccharides on spray efficacy. Seven treatments were tested, which included a control and six Sr treatments applied in various combinations with or without an adjuvant. Trees were sprayed four or eight times during the growing season, either directly to leaves and fruit or to leaves only (fruit covered during application). Spray treatments did not significantly affect total fruit fresh or dry weight. Although some discrimination between Ca and Sr was detected, the similar distribution of Ca and Sr in fruit tissue of control treatments suggested that Sr is a suitable tracer for Ca. Based on the covered vs. uncovered fruit treatments, about 11% to 17% of the Sr in the fruit came from Sr applied directly to the leaves. Eight spray applications over the growing season more than doubled both the concentration and content of fruit Sr compared with four late season sprays. The tested adjuvant doubled Sr absorption by and translocation to fruit compared with not using an adjuvant. Assuming similar transport for Ca and Sr, and adjusting for the atomic weight of Ca relative to Sr, the maximum increase in fruit Ca concentration at harvest from foliar and fruit applications (eight sprays with adjuvant and uncovered fruit) would have been as follows: core = 78 mg·kg–1; flesh = 35 mg·kg–1; peel = 195 mg·kg–1; entire fruit = 67 mg·kg–1. In addition to being an underused tool for studying Ca transport patterns, the results also suggest that use of Sr may be a novel technique for testing the efficacy of various adjuvants used to enhance uptake and transport of Ca in leaves and fruit.
`McIntosh' apple trees [Malus ×sylvestris (L.) Mill. Var domestica (Borkh.)] on five semidwarfing rootstocks (CG.4814, CG.7707, G.30N, M.7 EMLA, and Supporter 4) were planted at 10 locations (MA, MI MN NS 2 in NY ON PA VT and WI) under the direction of the NC-140 Multistate Research Project. After four growing seasons (through 2002), trees on CG.7707, G.30N, Supporter 4, and M.7 EMLA were significantly larger than those on CG.4814. Cumulative root suckering was most from trees on M.7 EMLA, and least from trees on CG.7707, G.30N, and Supporter 4. Yield per tree in 2002 and cumulatively was greatest from trees on G.30N and least from trees on CG.7707 and M.7 EMLA. In 2002 and cumulatively, CG.4814 resulted in the greatest yield efficiency, and M.7 EMLA resulted in the lowest. In 2002, fruit from trees on M.7 EMLA were largest, and those from trees on CG.4814 were smallest. On average, M.7 EMLA resulted in the largest fruit, and G.30N resulted in the smallest. Limited data will be presented on CG.6210, CG.8, G.30T, and M.26 EMLA, which are planted only at some locations. Data for the fifth season (2003) will be presented.
`McIntosh' apple trees [Malus ×sylvestris (L.) Mill. Var domestica (Borkh.)] on 10 dwarfing rootstocks (CG.3041, CG.4013, CG.5179, CG.5202, G.16N, G.16T, M.9 NAKBT337, Supporter 1, Supporter 2, and Supporter 3) were planted at 10 locations (MA, MI MN NS 2 in NY ON PA VT and WI) under the direction of the NC-140 Multistate Research Project. After four growing seasons (through 2002), trees on CG.5202 and CG.4013 were significantly larger than those on all other rootstocks. Smallest trees were on M.9 NAKBT337. Trees on other rootstocks were intermediate. Rootstock did not influence cumulative root suckering. Yield per tree in 2002 was greatest from trees on CG.4013 and lowest from trees on M.9 NAKBT337; however, cumulatively, trees on M.9 NAKBT337 and CG.4013 yielded the most. Yield efficiency in 2002 was not affected by rootstock. Cumulatively, rootstock had very little effect, but trees on CG.5202 were the least efficient. In 2002, M.9 NAKBT337, CG.3041, and Supporter 2 resulted in the largest fruit, and CG.5179 resulted in the smallest. On average, M.9 NAKBT337 resulted in the largest fruit, and G.16T resulted in the smallest. Limited data will be presented on CG.5935 and M.26 EMLA, which are planted only at some locations. Data for the fifth season (2003) will be presented.
Researchers have collected a considerable amount of data relating to apple (Malus ×domestica) cultivars and rootstocks over the past 30 years, but much of this information is not easily accessible. The long-term goal of our working group is to increase access to this information using online technology available through eXtension. In eXtension, researchers and extension personnel are developing a community of practice (CoP) to increase the quality and amount of online information for individuals interested in our work [referred to as a community of interest (CoI)]. For this project, our CoI is broadly defined as commercial apple producers, nursery professionals, county extension educators, Extension Master Gardeners, home gardeners, and consumers. Our CoP is developing diverse educational tools, with the goals of increasing productivity, profitability, and sustainability for commercial apple production. Additionally, we will provide other members of our CoI access to research-based, reliable information on the culture of apples. We chose to begin our focus on cultivars and rootstocks adapted to the eastern United States and will add other U.S. regions as our resources and interest in our project grows.