Strawberry cultivars vary in productivity, sugars and phytonutrient content when grown in a greenhouse during the winter

In many areas of the US, fresh locally grown berries are not available during the winter. With this in mind, a research study comprised of three experiments was conducted focused on cultivar selection for berry yield, number, sweetness and phytonutrient content. Using a capillary mat system with under bench heating within a double-layer polyethylene greenhouse, strawberries were grown in the Great Plains Region of the US during the winter. During experiment 1, 12 cultivars were grown; berries were weighed, counted and analyzed for sugars and phytonutrients. “Albion” plants produced a high number/mass of berries, had relatively high sugar content but a lower level of phytonutrients when compared to other cultivars. Sugar and phytonutrients concentrations overlapped across cultivars and thus, one cultivar could not be statistically singled out as best. As all cultivars flowered and fruited, two additional 8-month-long experiments were conducted. It took only 7 weeks from potting of dormant crowns for most cultivars to produce fruit. Certain cultivars fruited more successfully during certain months than others, but this was not associated with response time. For example,” “Albion”, “Chandler”, “Darselect”, “Evie-2” and “Seascape” plants consistently produced fruit October to early January while “AC Wendy”, “Cavendish”, “Honeoye” and “Strawberry Festival” plants mainly produced berries in March/April. Summed over experiment 2, “Albion”, “ Cavendish”, “Chandler”, “ Evie-2”, “Portola” and “Seascape” plants produced the greatest mass of berries. “AC Wendy” and “Darselect” berries contained some of the highest levels of sugars while berries from “Chandler”, “Darselect”, “Evie-2”, “Seascape” and “Strawberry Festival” had some of the highest phytonutrient values. In the third experiment, of the 8 selected cultivars, “Evie-2”, “Evie−2+” and “Portola” plants had the highest total yield and average berry mass/plant. “Seascape” and” Chandler” plants were second in total production. Glucose, fructose and sucrose levels varied across cultivars with “Chandler” and “Seascape” berries possessing the lowest level of total sugars. Phytonutrient values varied among cultivars with some having better flavonoids (“Seascape”), phenols (“Seascape” and “Chandler”) and ant oxidant capacity (“Seascape”, “Evie-2” and “Cavendish”). Measurement of soluble solids concentration varied by week among the cultivars with “Seascape”, “Seascape+”, and “Albion” berries possessing higher levels than other cultivars such as “Cavendish”. Overall, under these winter greenhouse conditions using capillary mat fertigation and an under-bench heat delivery system, strawberries were successfully produced for the off-season market

Delay of Bud Break on \u27Edelweiss\u27 Grapevines with Multiple Applications of Amigo Oil and NAA

‘Edelweiss’ is an important grape cultivar grown in the Midwestern part of the USA. This grapevine is tolerant to extreme winter temperatures which can be experienced in the areas where it is most widely grown. ‘Edelweiss’ is one of the earliest cultivars in the vineyard to break bud, making it very susceptible to late spring freezes. The primary buds of ‘Edelweiss’ produce a significant amount of fruit, while unlike many other hybrids, the secondary and tertiary buds will have little to no yields, thus making it important to protect the primary buds from a late freeze. The objective of this research was to determine if multiple applications of Naphthaleneacetic acid (NAA) or Amigo Oil has a greater effect on bud delay when compared to single applications. ‘Edelweiss’ vines were treated with one, two, or three applications of NAA or Amigo Oil at monthly intervals starting in early January. The purpose of the Amigo Oil and NAA application was to delay bud break without affecting desired characteristics such as yield or fruit composition. Amigo Oil was applied at 10% concentration (v/v) and the NAA at 1000 ppm with a custom built all-terrain vehicle (ATV) sprayer. All treatments of Amigo Oil led to a significant bud break delay ranging from 3 to 11 days as compared to the control. None of the treatments resulted in negative effects on yield or fruit characteristics. A controlled laboratory experiment was also conducted, where single bud cuttings were forced in forcing solution containing 200 ppm 8-hydroxyquinoline citrate and 2% sucrose at 25°C under 12 hour days. Treatments of one, two, or three applications of 1000 ppm NAA and 10% (v/v) Amigo Oil were applied to single buds at weekly intervals. Julian days until bud break were recorded and treatment-related bud break delays were observed. Two and three applications of oil significantly delayed bud break ranging from 14 to 24 days. All NAA treatments led to significant bud delay ranging from 6 to 9 days. Grape growers in climates with the potential of late spring freezes may consider the use of Amigo Oil as a potential means to protect their vines from freeze injury. Advisor: Paul E. Rea

Replacing Herbicides with Groundcovers to Enhance Vineyard Sustainability

In many Midwestern vineyards a three to four-foot weed-free strip is maintained directly beneath the vines to reduce vine-weed competition. Conventionally, this strip has been conserved with repeated applications of herbicide, mainly glyphosate. The necessity for this weed-free strip to reduce vine-weed competition has been well documented in more arid climates. However, in areas with higher soil fertility and adequate rainfall, this strip may be unnecessary. Moreover, stand establishment and early vine growth have not been well documented when planting groundcovers (GC) immediately following the vine planting. The main objective of this project is to assess the severity of competition for water between ‘Edelweiss’ grapevines and neighboring permanent GC treatments. In year one (2014), the vineyard and GCs were established, where the GCs were planted immediately after the vines. Midday leaf water potential (Ψmd) measurements began in 2015 and lasted through 2017 to assess water competition between vines and GCs. Additional data collected during the four year project included: pruning weights, bud break, yield and fruit quality and soil nutrition. Generally, GC treatments had lower Ψmd than the herbicide sprayed control, however, none of the treatments exhibited even slight water stress. Vine-GC competition was most apparent in the three years of pruning weights, where the most native grass GC treatment had up to 99% in 2014, 193% in 2015 and 183% in 2016 lower weights than the control. Harvest in 2016 and 2017 showed significantly lower yields between GC treatments and the control. However, no differences were found in berry quality (pH, Titratable Acidity, °Brix). An additional greenhouse project was done to define water stress thresholds for ‘Edelweiss’ grapevines using Ψmd and high resolution thermal infrared images. Fully irrigated and 14-day dry vines exhibited a Ψmd of -8.7 bars and -13.3 bars, respectively. The grapevines exhibited a mild, moderate and severe water stress level at 8, 10 and 12 days-dry, respectively (Ψmd of -12 bars, -12.5 bars and -13 bars). Results suggest that planting groundcovers in both the alleyways and in-row areas of the vineyard during the first year of establishment is detrimental to vine growth and causes reduced yields. Advisor: Paul E. Rea

Growth of Black Walnut in Southeast Nebraska

Black walnut (Juglans nigra L.), within the family Juglandaceae, is a premier hardwood timber species in the United States. Its native range encompasses most of the eastern U.S., roughly extending from eastern South Dakota and eastern Texas on its western edge to Massachusetts and western Florida in the east (Figure 1). The occurrence and productivity of black walnut on the western edge of its native range, including eastern Nebraska, is largely a function of available water during the growing season. However, black walnut has been extensively planted west and north of its native range. Studies have shown black walnut can withstand moving 200 miles northward from its native range without likelihood of cold injury (Bey, 1980). Black walnut is sensitive to soil conditions. It grows best on deep, well-drained, nearly neutral soils that are generally moist and fertile (Williams, 1990). Black walnut grows in many mixed mesophytic forests, but it is seldom abundant (Schlesinger & Funk, 1977). Usually it is found scattered among other tree species. Pure stands are rare, relatively small, and usually located on the edge of its native range (Williams, 1990). Although there is no universal vegetative indicator, the presence of Kentucky coffeetree (Gymnocladus dioicus) seems to indicate a good walnut growing site (Brinkman, 1965). In general, where white ash, red oak, sugar maple, slippery elm, or yellowpoplar grow well, black walnut also thrives. The majority of black walnut trees occur in natural stands. Walnut plantations (ca. 13,800 ac) account for only about 1 percent of the black walnut timber volume harvested in the U.S. each year (Shifley, 2004), even though black walnut has been cultivated since 1686 (Michler, Woeste & Pijut, 2007). Eight states currently have the greatest volume of black walnut growing stock on timberland: Missouri, Ohio, Iowa, Indiana, Illinois, Tennessee, West Virginia, and Michigan (Shifley, 2004). Black walnut is classified as a “shade intolerant” tree. It tends to develop a straight, limb-free trunk when growing as a dominant and/ or co-dominant tree under competition with other forest trees. It typically forms a taproot and wide-spreading lateral roots. The growing season of black walnut ranges from 140 days in the north to 280 days in western Florida. Annual precipitation in its native range varies from less than 25 inches in northern Nebraska to more than 70 inches in the Appalachian Mountains of Tennessee and North Carolina (Williams, 1990). Black walnut is prized for its chocolate- brown, straight-grained wood which is used to make fine furniture, expensive gunstocks, and high-quality veneer products. The nuts of the black walnut are relished as food by humans and animals. Black walnut nutmeats are often used in baked goods (cookies, cakes, etc.) and ice cream products. The healthful nutmeats are low in sugar and saturated fats, high in polyunsaturated and monounsaturated fats, a good source of protein and fiber, and contain no cholesterol (USDA-ARS, 2004). Even the nut shells are made into useful products. During World War II, engine pistons were cleaned with a “nut shell” blaster. Later, the automobile industry used ground black walnut shell to de-burr precision gears (Williams, 1990). Today, ground black walnut shell is used in a variety of products—a soft abrasive to clean jet engines, electronic circuit boards, ship and automobile gear systems, a filler in dynamite, a filter agent for smokestack scrubbers, and in oil drilling

Replacing Herbicides with Groundcovers to Enhance Vineyard Sustainability

In many Midwestern vineyards a three to four-foot weed-free strip is maintained directly beneath the vines to reduce vine-weed competition. Conventionally, this strip has been conserved with repeated applications of herbicide, mainly glyphosate. The necessity for this weed-free strip to reduce vine-weed competition has been well documented in more arid climates. However, in areas with higher soil fertility and adequate rainfall, this strip may be unnecessary. Moreover, stand establishment and early vine growth have not been well documented when planting groundcovers (GC) immediately following the vine planting. The main objective of this project is to assess the severity of competition for water between ‘Edelweiss’ grapevines and neighboring permanent GC treatments. In year one (2014), the vineyard and GCs were established, where the GCs were planted immediately after the vines. Midday leaf water potential (Ψmd) measurements began in 2015 and lasted through 2017 to assess water competition between vines and GCs. Additional data collected during the four year project included: pruning weights, bud break, yield and fruit quality and soil nutrition. Generally, GC treatments had lower Ψmd than the herbicide sprayed control, however, none of the treatments exhibited even slight water stress. Vine-GC competition was most apparent in the three years of pruning weights, where the most native grass GC treatment had up to 99% in 2014, 193% in 2015 and 183% in 2016 lower weights than the control. Harvest in 2016 and 2017 showed significantly lower yields between GC treatments and the control. However, no differences were found in berry quality (pH, Titratable Acidity, °Brix). An additional greenhouse project was done to define water stress thresholds for ‘Edelweiss’ grapevines using Ψmd and high resolution thermal infrared images. Fully irrigated and 14-day dry vines exhibited a Ψmd of –8.7 bars and –13.3 bars, respectively. The grapevines exhibited a mild, moderate and severe water stress level at 8, 10 and 12 days-dry, respectively (Ψmd of –12 bars, –12.5 bars and –13 bars). Results suggest that planting groundcovers in both the alleyways and in-row areas of the vineyard during the first year of establishment is detrimental to vine growth and causes reduced yields

Replacing Herbicides with Groundcovers to Enhance Vineyard Sustainability

In many Midwestern vineyards a three to four-foot weed-free strip is maintained directly beneath the vines to reduce vine-weed competition. Conventionally, this strip has been conserved with repeated applications of herbicide, mainly glyphosate. The necessity for this weed-free strip to reduce vine-weed competition has been well documented in more arid climates. However, in areas with higher soil fertility and adequate rainfall, this strip may be unnecessary. Moreover, stand establishment and early vine growth have not been well documented when planting groundcovers (GC) immediately following the vine planting. The main objective of this project is to assess the severity of competition for water between ‘Edelweiss’ grapevines and neighboring permanent GC treatments. In year one (2014), the vineyard and GCs were established, where the GCs were planted immediately after the vines. Midday leaf water potential (Ψmd) measurements began in 2015 and lasted through 2017 to assess water competition between vines and GCs. Additional data collected during the four year project included: pruning weights, bud break, yield and fruit quality and soil nutrition. Generally, GC treatments had lower Ψmd than the herbicide sprayed control, however, none of the treatments exhibited even slight water stress. Vine-GC competition was most apparent in the three years of pruning weights, where the most native grass GC treatment had up to 99% in 2014, 193% in 2015 and 183% in 2016 lower weights than the control. Harvest in 2016 and 2017 showed significantly lower yields between GC treatments and the control. However, no differences were found in berry quality (pH, Titratable Acidity, °Brix). An additional greenhouse project was done to define water stress thresholds for ‘Edelweiss’ grapevines using Ψmd and high resolution thermal infrared images. Fully irrigated and 14-day dry vines exhibited a Ψmd of –8.7 bars and –13.3 bars, respectively. The grapevines exhibited a mild, moderate and severe water stress level at 8, 10 and 12 days-dry, respectively (Ψmd of –12 bars, –12.5 bars and –13 bars). Results suggest that planting groundcovers in both the alleyways and in-row areas of the vineyard during the first year of establishment is detrimental to vine growth and causes reduced yields

Greenhouse Production of Strawberries During the Winter

Strawberries are one of America’s favorite fruits and are available in grocery stores year round. Given increased shipping and other associated costs as well as the opportunity to provide a fresh, nutritious, local product, our research team is exploring the feasibility of growing strawberries during the winter in Nebraska

Strawberry cultivars vary in productivity, sugars and phytonutrient content when grown in a greenhouse during the winter

In many areas of the US, fresh locally grown berries are not available during the winter. With this in mind, a research study comprised of three experiments was conducted focused on cultivar selection for berry yield, number, sweetness and phytonutrient content. Using a capillary mat system with under bench heating within a double-layer polyethylene greenhouse, strawberries were grown in the Great Plains Region of the US during the winter. During experiment 1, 12 cultivars were grown; berries were weighed, counted and analyzed for sugars and phytonutrients. “Albion” plants produced a high number/mass of berries, had relatively high sugar content but a lower level of phytonutrients when compared to other cultivars. Sugar and phytonutrients concentrations overlapped across cultivars and thus, one cultivar could not be statistically singled out as best. As all cultivars flowered and fruited, two additional 8-month-long experiments were conducted. It took only 7 weeks from potting of dormant crowns for most cultivars to produce fruit. Certain cultivars fruited more successfully during certain months than others, but this was not associated with response time. For example,” “Albion”, “Chandler”, “Darselect”, “Evie-2” and “Seascape” plants consistently produced fruit October to early January while “AC Wendy”, “Cavendish”, “Honeoye” and “Strawberry Festival” plants mainly produced berries in March/April. Summed over experiment 2, “Albion”, “ Cavendish”, “Chandler”, “ Evie-2”, “Portola” and “Seascape” plants produced the greatest mass of berries. “AC Wendy” and “Darselect” berries contained some of the highest levels of sugars while berries from “Chandler”, “Darselect”, “Evie-2”, “Seascape” and “Strawberry Festival” had some of the highest phytonutrient values. In the third experiment, of the 8 selected cultivars, “Evie-2”, “Evie−2+” and “Portola” plants had the highest total yield and average berry mass/plant. “Seascape” and” Chandler” plants were second in total production. Glucose, fructose and sucrose levels varied across cultivars with “Chandler” and “Seascape” berries possessing the lowest level of total sugars. Phytonutrient values varied among cultivars with some having better flavonoids (“Seascape”), phenols (“Seascape” and “Chandler”) and ant oxidant capacity (“Seascape”, “Evie-2” and “Cavendish”). Measurement of soluble solids concentration varied by week among the cultivars with “Seascape”, “Seascape+”, and “Albion” berries possessing higher levels than other cultivars such as “Cavendish”. Overall, under these winter greenhouse conditions using capillary mat fertigation and an under-bench heat delivery system, strawberries were successfully produced for the off-season market