Dudaim melon (Cucumis melo Group Dudaim) is a unique edible melon for which few postharvest physiology studies have been conducted. To investigate the postharvest behavior of dudaim melon, two cultivars (Zangi-Abad and Kermanshah) were planted, tagged at anthesis, and harvested at two maturity stages: 21 and 28 d after anthesis (DAA). Harvested fruit were stored at 5 or 13 °C for up to 3 weeks and various quality parameters including color, firmness, titratable acidity (TA), total soluble solids (TSS), weight loss, chilling injury (CI), ethylene production, protein content, glucose content, fructose content, sucrose content, and maltose content were assessed during storage. After 3 weeks of storage at 13 °C, early-harvested fruit (21 DAA) had relatively similar color values (L*, lightness; a*, green–red tones; b*, blue–yellow tones) and TA compared with late-harvested fruit (28 DAA); however, some quality traits, such as TSS, were not similar. Ethylene content decreased initially after harvest and then started to increase during storage at 13 °C. For most treatments, glucose and fructose contents decreased whereas sucrose and maltose contents increased with advancing maturity. Increased ethylene production, in concert with color development at 13 °C, similar to ripe fruit, and the changing balance of measured mono- and disaccharide sugars in harvested fruit likely indicates ‘Kermanshah’ is climacteric. Results for ‘Zangi-Abad’ were not as definitive. Dudaim melon fruit can be harvested at an optimum stage of maturity, similar to known climacteric melon fruit, and then allowed to ripen at proper storage temperatures before consumption. Based on the results of this study, we recommend that harvest at 21 DAA and storage at a nonchilling temperature such as 13 °C are the optimal stage and temperature for long storage purposes.
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Mohsen Hatami, Siamak Kalantari, Forouzandeh Soltani and John C. Beaulieu
Cristian E. Loyola, John M. Dole and Rebecca Dunning
In the United States and Canada, there has been an increase in the demand for local specialty cut flowers and a corresponding increase in production. To assess the needs of the industry, we electronically surveyed 1098 cut flower producers and handlers in the United States and Canada regarding their current cut flower production and postharvest problems, and customer issues. We received a total of 210 responses, resulting in a 19% response rate. The results showed that the main production problem was insect management; crop timing was the second most important problem and disease management was the third. Crop timing encompasses a range of related issues such as determining the correct harvest stage, harvest windows that are too short, flowering all at once, or lack of control when the crop is ready to harvest. The main postharvest problems were temperature management, hydration, and flower food management. Timing and stem length were the two most mentioned species-specific production issues, with each one listed by 10% or more of the respondents for eight of the total 31 species. Regarding on-farm postharvest handling, hydration and vase life were the two most mentioned issues; they were reported for five and three species, respectively. For postharvest during storage and transport, damage and hydration were the most common issues; these were listed for three species each. The most commonly mentioned customer complaints were vase life and shattering, which were reported for six and two species, respectively. These results will allow researchers and businesses to focus on the major cut flower production and postharvest issues and on crops that are most in need of improvement in North America.
Jaysankar De, Aswathy Sreedharan, You Li, Alan Gutierrez, Jeffrey K. Brecht, Steven A. Sargent and Keith R. Schneider
Cooling procedures used by blueberry (Vaccinium sp.) growers often include delays up to 24 hours that can damage the fruit through rough handling and adverse temperatures, thereby potentially compromising quality and, subsequently, safety. The objectives of this experiment were to compare forced-air cooling (FAC) compared to hydrocooling without sanitizer (HW) and hydrocooling with sanitizer (HS) regarding the quality and shelf life of southern highbush blueberry [SHB (Vaccinium corymbosum)] and to determine the efficacy of these treatments for reducing Salmonella in SHB. Freshly harvested SHB that were inoculated with a five-serovar cocktail of rifampin-resistant Salmonella were rapidly chilled by FAC or hydrocooling (HW and HS) using a laboratory model system. FAC did not show any significant reduction (P > 0.05) in Salmonella or in the effects on the microbiological quality of blueberries. HW and HS reduced Salmonella by ≈2 and >4 log cfu/g SHB, respectively, on day 0. These postharvest treatments was also evaluated for their ability to help maintain fruit quality throughout a storage period of 21 days at 1 °C. Hydrocooling (both HS and HW) provided more rapid cooling than FAC. Hydrocooled blueberries showed significant weight gain (P < 0.05), whereas FAC resulted in a slight, but insignificant (P > 0.05), reduction in final weight. The results of hydrocooling, both HS and HW, shown in this study could help to extend the shelf life while maintaining or increasing the microbiological quality of fresh market blueberries. Information obtained by this study can be used for developing the best temperature management practices to maintain the postharvest safety and quality of blueberries.
George E. Boyhan, Suzanne O’Connell, Ryan McNeill and Suzanne Stone
Organic production is a fast-growing sector of agriculture in need of variety evaluations under their unique production systems. This study evaluated 16 watermelon (Citrullus lanatus) varieties for their performance characteristics under organic production practices. Plants were grown on plastic mulch-covered beds on land that had been certified organic in accordance with the U.S. Department of Agriculture National Organic Program. Six of the entries were F1 hybrids; the remaining entries were open-pollinated (OP) varieties. Of the 10 OP varieties, three were considered heirloom varieties, including Cream of Saskatchewan, Georgia Rattlesnake, and Moon & Stars. ‘Georgia Rattlesnake’ was the highest yielding variety and had the greatest average fruit weight. Along with ‘Georgia Rattlesnake’, ‘Nunhems 800’, ‘Nunhems 860’, ‘Orangeglo’, and ‘SSX 8585’ were included in the top five yielding varieties. The top five yielding varieties had fruit size that averaged more than 20 lb. Fruit size correlated with rind thickness, with lighter fruit having thinner rind (Pearson’s correlation, r = 0.779), which is not unexpected. ‘Sangria’ had the greatest average soluble solids content at 11.2%, which was greater than all entries with soluble solids less than 10%.
Analena B. Bruce, Elizabeth T. Maynard and James R. Farmer
High tunnels are an increasingly popular part of the infrastructure among small and diversified farms that market their products directly to consumers. In addition to extending the growing season, research has strongly indicated that high tunnels can increase yield, enhance shelf life, and improve the quality of crops grown. The objective of this study was to gain a better understanding, from the perspective of farmers, of the challenges and opportunities associated with adopting high tunnels for specialty crops in Indiana. We collected information through a case study that included questionnaires and in-depth interviews with 20 farmers. We found that the additional labor and time requirements of high tunnel production, the increased complexity of high tunnel production, soil fertility, and disease management, and limited winter markets posed the greatest challenges. The ability to differentiate their products based on higher quality and longer shelf life, the ability to obtain a premium price, the ability to have a source of income during the off-season, and the ability to produce complementary crops were the most important opportunities for using high tunnels. This research implied ways to expand opportunities and reduce barriers to maximizing the potential of high tunnels. Understanding the human dimensions of managing high tunnels is important for providing extension educators and Natural Resources Conservation Service field staff with better knowledge of the common difficulties and benefits of this technology so they are better able to advise farmers considering investing in a high tunnel. A focus on the human dimensions is also helpful for identifying research priorities to evaluate new approaches to decreasing problems and increasing benefits. Consequently, this study provided an in-depth understanding of farm-level challenges associated with high tunnel adoption to improve future research in diverse fields.
Alberto Sánchez-Estrada and Julián Cuevas
In countries new to producing ‘Manzanillo’ olive trees (Olea europaea), free cross-pollination is often insufficient to obtain high levels of fruit set. An appropriate pollination design is therefore essential to ensure a timely, abundant, and compatible pollen supply. With a view to determining whether a pollination deficit exists in a nontraditional olive area such as the northern Mexico, pollination experiments were carried out in two consecutive seasons in both a monovarietal and a multivarietal Manzanillo orchard, where Sevillano, Barouni, Picual, Pendolino, Mission, Nevadillo, and Frantoio trees were growing nearby. The pollination treatments were self-, open, and cross-pollination with ‘Barouni’ and ‘Sevillano’ pollen, the latter only in the multivarietal orchard. The results confirmed the full self-incompatible condition of ‘Manzanillo’. Open-pollination did not improve fruit set in the monovarietal orchard, but it did so significantly in the multivarietal plot, where fruit set levels under open-pollination matched those of cross-pollination. Lower pollen adhesion, as well as occasional decreased germination, and reduced and delayed pollen tube growth were observed under self-pollination, highlighting self-incompatibility reactions. The reduction in fertilization rates led to low fruit set under self-pollination. Positive effects of open- and cross-pollination treatments were also noted on fruit weight (despite higher crop loads) and pulp-to-pit ratios. A strategic plantation design, including appropriate pollinizers in the right number and position, is therefore suggested for increasing ‘Manzanillo’ fruit quality and yield in Mexico. Both ‘Barouni’ and ‘Sevillano’ served as efficient pollinizers for ‘Manzanillo’, although we recommend ‘Barouni’ as a more efficient because the bloom periods of them matched that of ‘Manzanillo’
Jia Liu, Tingting Xue and Yongbao Shen
Freshly harvested empress tree (Paulownia elongata) seeds have physiologic dormancy. The aim of this study was to investigate the effects of exogenous and endogenous nitric oxide (NO) on the dormancy and germination of empress tree seeds. After treatment with different concentrations of sodium nitroprusside (an NO-releasing compound) solution, the germination percentage of seeds under 12 h of continuous light was significantly greater. Seed germination percentage was promoted significantly by 10–4 M sodium nitroprusside plus cold stratification compared with seeds treated with cold stratification only. At different hours during imbibition, empress tree seeds treated with 2-(4-carboxyphenyl)-4, 4, 5, 5- tetramethylimidazoline -1-oxyl-3-oxide potassium salt (c-PTIO), NG-nitro-L-arginine methyl ester (L-NAME), and sodium tungstate showed reduced seed germination percentages. During the early hours of imbibition, c-PTIO or sodium tungstate treatment inhibited seed germination significantly. The results showed that both exogenous and endogenous NO can release empress tree seed dormancy. Endogenous NO oxide was involved in dormancy release and germination of seeds during the early stages of imbibition. Wider application of NO may be used for breaking seed dormancy in other species.
Yuanshuo Qu, Ryan M. Daddio, Patrick E. McCullough, Stacy A. Bonos and William A. Meyer
Methiozolin is a new herbicide that controls annual bluegrass (Poa annua) in turfgrasses, but the differential tolerance levels of fine fescues (Festuca sp.) has received limited investigation. The objective of this study was to investigate the potential injury from methiozolin when applied to chewings fescue (Festuca rubra ssp. fallax), strong creeping red fescue (Festuca rubra ssp. rubra), and hard fescue (Festuca brevipila). Nine different fine fescue populations (14W2 Comp, Fairmont, and Survivor chewings fescue; FT345, Miser, and Fenway strong creeping red fescue; and 14H4 Comp, Stonehenge, and Oxford hard fescue) were sprayed with methiozolin at five different rates (0.42, 0.83, 1.25, 1.67, and 2.09 lb/acre) at four different application timings [4 weeks before seeding (WBS), 2 WBS, at seeding (AS), and 2 weeks after germination (WAG)]. Untreated controls were also included for each combination. Significant reduction in germination of fine fescue was observed when methiozolin was applied before emergence for all tested application rates. Methiozolin at 1.25, 1.67, and 2.09 lb/acre applied before or at the day of seeding led to complete inhibition of germination in all fine fescue species tested. It was less injurious compared with methiozolin applied at 2 WAG, although a reduction in the percentage of green cover and biomass was observed for application rates greater or equal to 0.83 lb/acre. The hierarchical ranking of species injury from high to low is as follows: hard fescue, chewings fescue, and strong creeping red fescue. A possible solution for annual bluegrass control in fine fescue species with methiozolin is multiple postemergence applications up to a maximum rate of 0.83 lb/acre. Turf managers need to make adjustments in methiozolin application rates and timings based on fine fescue species to maximize selectivity for annual bluegrass control.
Robert F. Heyduck, Steven J. Guldan and Ivette Guzmán
In a two-part study, we examined the effect of sowing date and harvest schedule on the yield of spinach (Spinacia oleracea) grown during the winter in 16 × 32-ft-high tunnels in northern New Mexico. Each part of the study was conducted for two growing seasons and took place between 2012 and 2015. In Study A (2012–13 and 2013–14), spinach was sown four times at roughly 2-week intervals (mid-October, early November, mid-November, and early December) and plant density (plants per square foot), plant height (centimeters), and yield (grams per square foot) were measured for three harvests in mid-January, mid-February, and mid-March. The earliest sowing date had the least-dense stands, and plant density increased with each subsequent sowing. The two earliest sowing dates had significantly higher season-long yield than the later two sowings. In Study B (2013–14 and 2014–15), all plots were sown in mid-October, but harvest schedule treatments were staggered such that harvests began at 9, 11, 13, or 15 weeks after sowing and continued at irregular intervals. Treatment 2, with harvests beginning after 11 weeks, had the greatest season-long yield, slightly greater than when harvests began at 9 weeks, and significantly more than when harvest began 13 weeks or later. More importantly, a staggered harvest schedule can provide spinach weekly for direct marketing opportunities.
David H Suchoff, Frank J. Louws and Christopher C. Gunter
Interest and use of grafted tomato (Solanum lycopersicum) in the United States continues to grow. Pioneered in Asia, herbaceous grafting is a commonly used cultural practice to manage many soilborne pathogens. Bacterial wilt (BW), caused by the pathogen Ralstonia solanacearum, is an aggressive soilborne pathogen that affects tomato grown in the southeastern United States. Traditional fumigation methods have limited effectiveness in the management of this pathogen. The present study was conducted to compare the bacterial wilt resistance of three commercially available tomato rootstocks, which are purported to be resistant to bacterial wilt: ‘Cheong Gang’, ‘RST-04-106-T’, and ‘Shield’. The determinate hybrid tomato ‘Red Mountain’, which is susceptible to bacterial wilt, was used as the scion and nongrafted control. Three locations were used over 2 years in North Carolina: an on-farm site with a history of bacterial wilt and two North Carolina Department of Agriculture Research Stations with no recent history of bacterial wilt. No disease symptoms were observed in any of the three grafted treatments, whereas the nongrafted controls showed between 30% and 80% disease incidence at the on-farm location. The resultant rootstock-imparted resistance improved marketable yields by between 88% and 125% compared with the nongrafted plants. When grown in locations lacking BW there were no yield benefits to grafting with any of the three rootstocks.