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Open access

Haruna Kobayashi, Kiyomi Hashimoto, Erika Ohba, and Yohei Kurata

Light-emitting diodes (LEDs) are known to affect plant morphology. In this study, we examined the relationship between changes in stem and root morphology in Populus sieboldii × Populus grandidentata induced by irradiation with blue (450 nm), red (630 nm), and white (combination of red, blue, and green; 525 nm) LED lights. Populus samples were reared for 36–55 days in separate LED incubators, and changes in their appearance were observed. After rearing, the main stem of each seedling was cut, leaving a section of stem extending from the roots to ≈20 mm above the medium surface; this part was used for tensile testing. The tensile tests were performed to clarify the relationship between the tensile force and displacement until 100 mm. Irradiation with blue light produced the tallest seedlings. The highest dry weight (root and stem) and largest stem diameter were obtained under red light. The results of the tensile tests showed that the work required to displace seedlings 100 mm was highest in plants reared under red light, followed by white and blue light. Numerous root branches developed under red light, and taproots were longest in saplings reared under blue light. The observed differences in root system morphology that were induced by rearing under light of different wavelengths were reflected in the tensile force required to extract the trees from the medium. The morphological changes observed in roots are important given the role of roots in forests after landslides, earthquakes, and other disruptions.

Open access

Adam Karl, Whitney Knickerbocker, and Gregory Peck

Harvesting labor is the largest annual variable operating expense for apple (Malus ×domestica) orchard enterprises and is subject to escalating costs and shortages. In Europe, much of the cider apple harvesting is done with machinery, greatly reducing production costs. However, despite a rapid increase in hard cider production in North America over the past 15 years, mechanical cider apple harvesting has not been widely implemented. In this study, we compared mechanical with hand harvesting costs for model 5-, 15-, and 60-acre cider apple orchards located in New York using a partial budget model. Scale-appropriate harvesters were identified for use at each farm scale. Sensitivity analyses were used to test the cost differential for using each piece of machinery on varying orchard sizes and to model changes in labor costs. Across all orchard scales, we found that mechanically harvesting cider apples was more profitable than hand harvesting, with larger operations breaking even sooner and realizing greater returns than operations using hand harvesting. Mechanical harvesting costs broke even with hand harvesting in years 16, 7, and 5 and by year 30 reduced cumulative harvesting costs by 23%, 52%, and 53% in our 5-, 15-, and 60-acre model orchards, respectively. Increasing the orchard size resulted in greater returns from mechanical harvesting. Using the machinery in the 15-acre orchard scenario on a 30-acre farm resulted in costs breaking even with hand harvesting in year 3; by year 30, the cumulative costs resulted in 66% lower harvesting costs than hand labor. Mechanical harvesting remained profitable when labor wages were decreased and became more profitable in scenarios with increasing wages. For example, in the 60-acre orchard, mechanical harvesting cost 41% less than hand harvesting with a 2% annual compounding decrease in labor wages; with 2% annual compounding increase in labor wages, the mechanical harvesting cost was 63% less than hand harvesting. In addition to the cost savings, mechanical harvesting allows for harvesting cider apples with fewer logistical challenges, such as contracting, housing, and transporting migrant labor.

Open access

Jie Zeng, Ting Zhou, Donglin Zhang, and Wangxiang Zhang

Open access

Giovani Rossi, Floyd M. Woods, and Courtney P. Leisner

Blueberries are an important fruit crop in the Ericaceae represented by multiple Vaccinium species and ecotypes. In addition to their economic value, blueberry fruit is known for an abundance of specialized metabolites with known human health benefits. Phenolic compounds, which include flavonoids and anthocyanins, are an important class of compounds found in blueberry that are known to contribute to fruit flavor and quality and for having health-promoting properties. Previous surveys of phenolic compounds in blueberry have demonstrated considerable variability in concentration of these metabolites, which is associated with differences in environmental factors and cultivars surveyed. This study expands this knowledge by surveying total phenolic, flavonoid, and anthocyanin content in ripe fruits of 71 blueberry cultivars from one growing season in Michigan. Included in this diversity panel are three ecotypes of blueberry (northern highbush, southern highbush, and half highbush). Rubel, Legacy, and Friendship were among the seven cultivars with the highest content of each compound. Total phenolic content showed a 5.03-fold difference among the lowest and highest cultivars, and total flavonoid content and total anthocyanin content demonstrated a 2.66-fold and 6.37-fold difference between the lowest and highest content across cultivars, respectively. There was no significant impact of ecotype on phytochemical composition of ripe fruits. This study also represents the first large-scale analysis of total phenolic content using the Fast Blue BB (FBBB) reagent. Data from this study have the potential to aid in future breeding efforts to enhance the human health benefits of this economically important fruit crop.

Open access

Qingyang Sun, Yue Zhao, Shusheng Zhu, Fei Du, Ruzhi Mao, Lijing Liu, Yifan Zhu, Su Li, Meng Sun, and Bin Tian

Rain-shelter cultivation could protect grape berries from many diseases and affect grape berry quality. However, there have been few studies of the effects of rain-shelter cultivation on the accumulation of volatiles in Shuijing grapes grown in Yunnan Province. Therefore, the goal of this research was to explore the effects of rain-shelter cultivation on the accumulation of volatiles in Shuijing grape berries during development. The Shuijing grapes used during this study were grown in the Yunnan Province of southwest China in two consecutive vintages (2018 and 2019). The results showed that rain-shelter cultivation promoted grape ripening and inhibited volatiles synthesis in Shuijing grape berries. However, the application of rain shelters did not affect the accumulation patterns of volatiles; instead, it affected the concentrations of volatiles in Shuijing grape berries, especially during the maturation phase [12–15 weeks after flowering (WAF)]. The concentrations of isoprenoid-derived volatiles (2019), fatty acid-derived volatiles, and amino acid-derived benzenoids in Shuijing grape berries were decreased by rain-shelter cultivation during the maturation phase. The concentration of 2,5-dimethyl-4-methoxy-3(2H)-furanone (mesifurane) was also decreased by rain-shelter cultivation during the late maturation phase (14 and 15 WAF). A principal component analysis (PCA) indicated that the vintage had a much greater influence on the physicochemical parameters and volatiles of the Shuijing grape berries than the cultivation method. This work reveals the formation and accumulation patterns of volatiles of Shuijing grape berries under rain-shelter cultivation during development and has significance for exploring the potential of rain-shelter cultivation in grape-producing regions with excessive rainfall.

Open access

Maria Brym, Yuqing Fu, Noah Frade, Elizabeth Baldwin, and Alan H. Chambers

Strawberry (Fragaria ×ananassa) is grown during the winter months in subtropical southern Florida and must thrive in higher than average temperatures and limestone soils. This is the first strawberry cultivar trial in southern Florida to include ‘Florida Beauty’, ‘Florida Brilliance’, ‘Strawberry Festival’, ‘Florida Radiance’, ‘Sensation FL127’, and ‘Winterstar’. Overall, ‘Strawberry Festival’ and ‘Sensation FL127’ were the top yielding cultivars, with the highest average total yields of 0.7 and 0.8 kg/plant fresh fruit, respectively. ‘Sensation FL127’ had a 36% greater late-season marketable yield compared with ‘Strawberry Festival’. ‘Sensation FL127’ consistently had the greatest soluble solids content (7.6% to 8.7%). Overall, this study demonstrates significant differences in yield and fruit quality among the cultivars tested in southern Florida.

Open access

Marina L. Curtis and Gerardo H. Nunez

Courses are the main source of data analysis training for students. The statistical software training taught in those courses can affect student career readiness. However, lack of information about statistical software use in horticulture leads students and mentors to select statistics courses based on course availability and/or anecdotal evaluations. This research aimed to describe statistical software use trends in horticulture research to inform student course selection. We surveyed ≈50% of all articles published in HortScience, HortTechnology, and the Journal of the American Society for Horticultural Science (JASHS) between 2005 and 2020. We found that SAS, SPSS, and R were the most frequently used software packages in this period. SAS use frequency decreased in HortScience and JASHS, but not in HortTechnology. SPSS use increased in JASHS and R use increased in all journals. Results from this retrospective survey suggest that training in SAS, SPSS, and R can help align students with horticulture research practices.

Open access

Katherine Brewer, Mary Hockenberry-Meyer, Susan Galatowitsch, and Stan C. Hokanson

Prairie dropseed [Sporobolus heterolepis (A. Gray) A. Gray] is a critical North American native grass that is often not incorporated into prairie restoration seed mixes due to its low survival and growth rates. This project investigated using hydrogels, landscape plugs, and native field soil to improve the survival and growth of prairie dropseed. At three tallgrass prairie restoration sites at the Minnesota Landscape Arboretum, we planted prairie dropseed plugs in Fall 2019, Spring 2020, and Fall 2020. When grown in the field from 42 to 94 weeks, we found that potting mix–grown plugs had increased growth as measured by dry weight compared with plugs grown in native soils. Soil medium did not influence survival rates. The use of hydrogels did not demonstrate increased survival or growth compared with plugs planted with water. We recommend land managers and restorationists use plugs grown in commercial potting mix rather than grown in native soils, and we found no advantage in using hydrogels over watering at planting.

Open access

Kevin Athearn, Marina Burani-Arouca, Nicholas Dufault, Clyde Fraisse, Joshua Freeman, Robert Hochmuth, Tatiana Sanchez, Tatiana Borisova, Tyler Pittman, and Luke Harlow

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] growers choose transplanting dates every year considering multiple risk factors. Earlier harvests linked to earlier planting typically find more favorable markets, but earlier planting has higher risk of freeze damage. Research also indicates that risk of fusarium wilt (caused by Fusarium oxysporum f. sp. niveum) is higher during cooler weather, adding to the risk of planting earlier. Thus, growers need to balance market risk (e.g., getting a low price) and production risk (e.g., lower harvest or higher cost due to freezing temperatures or disease) in selecting a planting date. The objective of this analysis is to examine the effect of planting date on the distribution of potential economic returns and evaluate whether late planting could be a favorable risk-management strategy. Probability distributions are estimated for key risk factors based on input from watermelon growers, published price data, historical freeze data, experiment station trials, and expert discussions. The distribution of economic returns is then simulated for three planting windows (early, middle, and late) using simulation software. Results demonstrate planting date risk–return tradeoffs and indicate that late planting is unlikely to be preferable to middle planting, even when risk of fusarium wilt is high.