Hazelnut (Corylus avellana L.) is a monoecious, dichogamous plant species that flowers in winter and early spring. In traditional hazelnut growing regions, hazelnut cultivars generally express protandry where the male flowers bloom before the female flowers. Nut set requires that compatible pollen be shed when the stigmas of the main cultivar are receptive. In this study, the floral phenology and date of leaf budbreak of five selections and 19 hazelnut cultivars from Europe and North America were observed over 4 yr in southern Ontario, and results were compared with cumulative growing degree days (GDD). In the continental climate of southern Ontario, most cultivars showed protogyny. Flowering dates varied over the years with pollination occurring in a period of 2–3 wk in early spring. These cultivars were classified into early, mid, and late blooming types. A GDD model was a better tool than average daily temperatures to predict the flowering dates of catkins and female flowers. Averaged over years, most of the cultivars in this study have a female bloom that is likely too early for the pollen shed by most of the other cultivars. This would likely impact yields in a commercial orchard. However, ‘Jefferson’, ‘Gene’, and ‘Epsilon’ have late females that are receptive when other cultivars are shedding pollen.

Twenty-eight apple cultivars were selected for their potential for hard cider production in Ontario. An experiment was conducted to evaluate their horticultural potential in the province. After being planted in spring 2015, the trees were evaluated annually for their survival, tree height and spread, trunk growth, flowering dates, flower counts, fruit per tree, pre-harvest drop, crop load, fruit weight, fruit firmness, juicing extraction efficiency, and harvest dates. These horticultural attributes were sufficient to discriminate between cultivars. Additional exploratory analyses indicated a relationship between horticultural attributes and a cultivar’s origin, with British cider cultivars blooming the latest, American cider apples producing the most juice, and French cider cultivars having the highest pre-harvest fruit drop. Cultivars in this study that show promise for continued research in Ontario include Binet Rouge, Bramley’s Seedling, Breakwell, Bulmer’s Norman, Calville Blanc d’Hiver, Cline Russet, Cox Orange Pippin, Crimson Crisp^®, Dabinett, Enterprise, Esopus Spitzenberg, Golden Russet, GoldRush, Medaille d’Or, Porter’s Perfection, and Stoke Red.

Twenty-eight apple cultivars were selected for their potential for hard cider production in Ontario; their juice characteristics were measured in 2017 and 2018, beginning two years after planting in 2015. After being harvested and pressed, each juice sample underwent analyses to determine soluble solids concentration (SSC), titratable acidity (TA), pH, yeast assimilable nitrogen (YAN), and polyphenolic concentration. Soluble solids concentration ranged from 10.6 °Brix in Brown’s Apple to 18.3 °Brix in Ashmead’s Kernel. Titratable acidity ranged from 31 as mg malic acid per 100 mL juice in Sweet Alford to 191 as mg malic acid per 100 mL juice in Bramley’s Seedling. The pH ranged from 2.88 in Breakwell to 4.76 in Sweet Alford. Yeast assimilable nitrogen concentration ranged from 60 mg YAN·L⁻¹ juice in Medaille d’Or to 256 mg YAN·L⁻¹ juice in Bulmer’s Norman. Polyphenols in juice ranged from 131 μg gallic acid equivalents (gae)·mL⁻¹ juice in Tolman Sweet to 1042 μg gae·mL⁻¹ juice in Stoke Red. Firmness ranged from 6.3 kg in Yarlington Mill to 11.7 kg in GoldRush. The relationships between these variables were also analyzed, showing a connection between acidity and juicing efficiency as well as a relationship between polyphenol concentration and fruit weight. Exploratory analyses indicated that juice attributes can be used to distinguish between cultivars and their origins. Cider producers can use these data to determine what to expect in juice from these cultivars.

Baseline data on the boreal jack pine associated chanterelle (Cantharellus cibarius Fr.) and pine mushrooms (Tricholoma magnivelare (Peck) Redhead) in the Boreal Plain Ecozone of Saskatchewan were collected in five ecosites of productive mushroom areas. It investigated hourly weather parameters correlated with daily purchase volumes over 4 yrs; yield data over 5 yrs; and varying age, tree density, and species for presence of mushrooms in over 100 stands. All plots fell within the lichen jack pine (jP) ecosite with an overstory entirely of jack pine. The understory was dominated by reindeer lichen, bearberry, and blueberry. Plots were well- to rapidly drained, subxeric to submesic, with low nutrient regime. Both chanterelle and pine mushrooms were present in jack pine stands of < 20 yrs, with greatest occurrence in pure jack pine stands of 41–60 yrs in moderately open A-B canopy density. Weekly purchase data correlated with environmental parameters. Growing degree days (GDD) (base temperature 5 °C) + soil temperature (minimum 500 ± 70 GDD), + either soil moisture or precipitation (cumulative 50–100 mm) provided the highest regression value with chanterelle yield 6–13 wks prior to first appearance. The 5-yr total chanterelle yield from this region averaged 7100 kg·yr⁻¹. Chanterelle cap diameter was a good predictor of fresh weight and proxy for yield. Pine mushroom was < 10% of chanterelle yield, averaging 1.72 kg·ha⁻¹ over 4 yrs based on 5 days picking. With future climate predictions of warmer and moister conditions, timing of fruiting body appearance is anticipated to advance.

In recent years, new vineyards have been established in southwestern Ontario. The open water of Lake Erie provides some winter protection for Vitis hybrids and winter-hardy Vitis vinifera L. cultivars in this area. However, winter damage is possible when vines are grown distant from the open water or when lakes are frozen. To better understand the risks to winter survival, the dormancy and chilling phenology were studied over three winters from 2013–2016. Ten dormant canes of two V. vinifera cultivars, ‘Chardonnay’ and ‘Riesling’, were collected weekly from 1 September until 30 March from the mature vines in a commercial vineyard located at St. Williams (Ontario). The canes defoliated in early October, and the endodormancy was completed by the end of December. The cumulative chilling hours (0–7.2 °C) from defoliation until the completion of endodormancy were averaged 606 hours for ‘Chardonnay’ and 665 hours for ‘Riesling’. ‘Chardonnay’ buds were slightly less hardy than ‘Riesling’ to cold temperatures, with a threshold of about −24 °C for ‘Chardonnay’ and −25 °C for ‘Riesling’. Most primary buds of both cultivars died after 16 February 2015, and more than half died after 12 February 2014, due to severe low temperatures of −33.1 and −26 °C, respectively.

Ginseng replant disease (GRD) has had a major impact on the American ginseng (Panax quinquefolius L.) industry in Canada and is a threat to its survival. With only 150 yr of domestic ginseng cultivation, GRD and its effect on the industry in North America is well documented compared with replant diseases in other crops. However, minimal research has been published on the etiology and management of GRD. Research and observations of replant diseases of the major commercial Panax species worldwide are presented to propose mechanisms of GRD and potential management options. The available evidence suggests the specific involvement of the soil-borne fungus Ilyonectria mors-panacis (A.A. Hildebr.) A. Cabral & Crous combined with an unknown host-related factor as the ultimate cause of GRD, since other proposed mechanisms seem unlikely to have occurred in the diversity of regions where GRD is reported. Other abiotic and biotic factors influencing the severity of the disease are also likely to be involved. Given the lack of clarity in the scientific literature between problems associated with continuous cultivation of ginseng and true replant disease, a definition of GRD is proposed. The development of an effective and economical management regime will require a better understanding of the mechanisms of GRD. Potential management options include reducing ginseng debris after harvest of the first crop, preplant testing to identify low-risk sites for replanting, fumigation, alternative disinfestation techniques, and fungicides (including biofungicides) targeting I. mors-panacis.

Tomato vine decline (TVD) disease complex results in fruit yield loss, but what soil management strategies might mitigate it? In commercial fields with a history of TVD, five approaches (soil organic amendments and transplant treatments) were evaluated for their impact on fruit yield, fruit quality, and microbial abundance or diversity at four site-years. One site-year had very high TVD pressure and high variability with no yield differences, thus efforts focused on the remaining site-years. Marketable yield was not different among treatments but numerically followed a trend similar to total yield. Amending soil with poultry manure delayed maturity (i.e., increased proportion of green fruit) and had the greatest total yield increases of 17.2%, congruent with decreased abundance of root pathogens (Verticillium dahliae, Rhizopicnis vagum). Microbial DNA fingerprinting data of rhizospheres, roots and (or) stems suggested treatments did not significantly shift the total diversity fungal nor bacterial populations, but the aforementioned pathogen loads were reduced with the application of organic amendments relative to the untreated control. While drenching tomato transplants with pseudomonad culture increased their presence in roots, pathogen load was not reduced relative to the untreated control. Overall, these results show that soil organic amendments were able to improve tomato total yield in two of four site-years without reducing fruit quality (i.e., soluble solids, pH, colour), perhaps, in part, due to their ability to suppress specific root pathogens in commercial fields.

Neck rot caused by the fungus Botrytis allii Munn. is one of the most devastating diseases of onions (Allium cepa L.), resulting in significant yield losses. This disease is latent in nature developing symptomless onion plants in the field with bulbs typically showing symptoms 1–2 months after harvest in the storage. Molecular studies were conducted to detect latent infections of Botrytis neck rot in the onion fields of Manitoba, Canada. Plant samples of onion cultivars ‘Redwing’ and ‘Pocono’ were collected every 10 days throughout the growing season, starting from planting until bulb harvesting during 2018, 2019, and 2020 from a research farm in Brandon, Manitoba, and plant samples of ‘Redwing’ were collected during 2019 and 2020 from a commercial vegetable farm in Portage La Prairie, Manitoba. The amplified DNA fragment of onion leaves and the neck region of collected samples were subjected to polymerase chain reaction using the Botrytis-specific primer pair BA2f/BA1r. Botrytis allii was detected on onion samples collected from the commercial farm as early as the end of June 2019 and 2020 when plants were at the 5–7 leaf stage. The majority of onion samples collected from the research farm also started testing positive for the pathogen from June (2019, 2020) and July (2018) onwards. This knowledge about the timing of infection in the field will be useful in helping farmers to develop and evaluate management strategies in the field, and also predict the storability and availability of quality bulbs for sale.

To investigate whether low-level lighting is necessary and which narrow-band light spectra are effective in seed germination, seeds of 14 genotypes from begonia (Begonia × tuberosa), echinacea (Echinacea spp.), gerbera (Gerbera jamesonii), petunia (Petunia × hybrida), and vinca (Catharanthus roseus) were germinated under ultraviolet-B (UVB), blue (B), green (G), red (R), far-red (FR) light, or darkness. Light-emitting diode (LED) fixtures provided all spectrum treatments except for UVB, which was provided by a narrow-band fluorescent light. The photon flux density at seed level was ≈18 μmol·m⁻²·s⁻¹ for B, G, R, and FR, and 0.4 μmol·m⁻²·s⁻¹ for UVB. Based on daily germination observations, final germination percentage, germination onset time, germination time spread, and germination speed were compared among different spectrum treatments for each of the plant genotypes. There were no promotive effects on final germination percentage, germination onset time, and germination time spread under the narrow-band lights compared with darkness. For all plant genotypes, B had a similar effect as darkness on seed germination. FR inhibited seed germination relative to darkness by reducing final germination percentage by 31%–88%, delaying germination onset time by 30%–40%, and decreasing germination speed by 11%–48% in some genotypes. Under R, G, and UVB compared with darkness, germination speed was promoted for begonia ‘Apricot Shade’, a light-requiring genotype, and inhibited for vinca ‘Burgundy’, a light-inhibited genotype. Therefore, lighting at low levels used in our study is unnecessary for seed germination of the tested species except light-requiring genotypes, where R, G, and UVB are the most promotive among the tested narrow-band lights.

To optimize light-emitting diode (LED) spectral recipes for gerbera (Gerbera jamesonii) seedling propagation, seed germination and seedling morphology, biomass, flowering, and storage quality were observed in four cultivars, ‘Midi Dark Purple’, ‘Majorette Red Dark Eye’, ‘Maxi Pink’, and ‘Maxi White’, under six spectrum treatments: (1) FL, cool white fluorescent light; (2) RB, a photon flux ratio of 85% red and 15% blue (RB-LED); (3) RB + UVB, RB-LED combined with 0.5 μmol·m⁻²·s⁻¹ of ultraviolet-B; (4) RB + UVA, RB-LED combined with 9.6 μmol·m⁻²·s⁻¹ of ultraviolet-A; (5) RB + G, a photon flux ratio of 60% red, 15% blue, and 25% green; (6) RB + FR, RB-LED combined with 17.3 μmol·m⁻²·s⁻¹ of far-red. For all treatments, the photosynthetic photon flux density was 165 μmol·m⁻²·s⁻¹ under a 16-h photoperiod. Seedling growth and morphology were similar under FL and RB for all cultivars, except for a wider canopy of ‘Majorette Red Dark Eye’ under RB. Each of the tri-chromatic light treatments (i.e., RB + UVB, RB + UVA, RB + G or RB + FR) showed similar effects as RB, except for thicker ‘Maxi Pink’ stems under RB + FR. Furthermore, the quality index, an integrated evaluation of seedling quality, was similar under all the treatments for each cultivar. Given the similar seedling quality and the advantages of LEDs, RB-LED can potentially replace FL for controlled-environment gerbera seedling production, but the tri-chromatic lights tested in this study appear to be unnecessary.

Microgreens growing under electric (artificial) lighting in controlled environments often have short hypocotyls, which can be difficult for machine harvest. To investigate whether early-stage dark treatment can promote hypocotyl elongation without compromising microgreen yield and quality, two different seed-size species, sunflower (Helianthus annuus ‘Black oil’) and arugula (Eruca sativa ‘Rocket’), were tested. Seeds of sunflower and arugula were sown in pots, and the pots were placed inside support trays. During the first 5 days after seeding, half of the pots per species within each tray were covered with an upside-down black tray as dark treatment, and another half were kept under light. The light treatment was provided by continuous (24-h) lighting with a combination of red (85%) and blue (15%) light-emitting diodes at a photosynthetic photo flux density of around 100 μmol·m⁻²·s⁻¹. After 5 days of dark treatment, the black covers were removed and the plants were grown under the above lighting treatment till harvesting. The microgreens were harvested at 7 d and 12 d after seeding for sunflower and arugula, respectively. Early-stage dark treatment promoted hypocotyl elongation by 26% and 28% for sunflower and arugula, respectively. Microgreen yield was increased by 13% for sunflower and reduced by 24% for arugula under dark treatment. Dark treatment increased cotyledon succulence by 14% for sunflower, but reduced cotyledon size by about 25% for arugula despite increases in red color and succulence of arugula hypocotyls. For both species, cotyledon color and soluble solids content were not affected by dark treatment.

Subirrigation systems are popular for reducing nutrient usage in indoor floricultural production. Two open subirrigation experiments were conducted in a commercial setting using multiple chrysanthemum cultivars and up to 75% less N–P–K than industry standards. The lowest N–P–K levels supplied in the nutrient solution (in mmol·L⁻¹: 5.4 N, 0.71−0.97 P, 1.9−4.1 K) up to bud break, were associated with acceptable leaf N–P–K levels [4.5−5.4% dry matter (DM), 0.23−0.60% DM, and 3.3−5.6% DM, respectively]. These findings validate our modified delivery practice and the use of lower N–P–K inputs in the production of subirrigated pot chrysanthemums.

Municipal solid waste (MSW) compost is used to enrich soils by virtue of its bio-physicochemical properties. However, undesirable accumulation of chemical elements can reduce soil quality and cause food safety issues. A 5-yr field study was carried out to investigate the impact of Compost Quality Alliance (CQA)-tested MSW compost application frequency (annual, biennial and no-compost) on soil quality and chemical element accumulation in edible portions of lettuce (Lactuca sativa cv. Grand Rapids), beet (Beta vulgaris cv. Detroit Supreme), carrot (Daucus carota cv. Nantes), and green bean (Phaseolus vulgaris cv. Golden Wax). Analysis of soil showed that chemical elements were highest in annual application followed by biennial, but less in control (no-compost) and fallow soils. Soil background levels of chemical elements influenced the concentrations of iron (Fe) and manganese (Mn) in green bean, aluminum (Al) in green bean and beet, and barium (Ba) in carrot, beet, and lettuce. Cadmium (Cd) concentration in beet, lettuce, and green bean grown in the annual plot was increased by 48%, 52% and 62%, respectively while carrot recorded a 56% increase in the biennial plot compared with no-compost. Bioaccumulation factors were < 1 for all of the essential and non-essential trace elements in all of the plant species, except boron (B) and molybdenum (Mo). However, lettuce showed a higher tendency to accumulate Cd, rubidium (Rb), and strontium (Sr). Overall, the health risk for human consumption is low. Although long-term annual application of compost to vegetables seemed safe for human consumption, it is necessary to continuously monitor potential chemical element accumulation, particularly non-essential trace elements in soils and plants.

Nitrogen (N) management is critical for sugarbeet (Beta vulgaris L.) because N inversely influences root yield and recoverable white sucrose per tonne (RWST). In Ontario, from 2015 to 2017, the use of optical sensors (e.g., a soil plant analysis development (SPAD) chlorophyll meter, GreenSeeker handheld crop sensor) was evaluated as a method to guide N application and harvest date (late-September, late-October) selection by predicting root yield RWST and partial profit margins. In a commercial field, 4 to 5 fertilizer N rates, and 8 to 12 cultivars were tested in a split block design experiment with three replications and two harvest dates. In all years, few cultivars (≤2) had a root yield response to applied N, which was attributed to high inherent soil fertility, and limited our evaluation of optical sensors to adjust in-season N applications. The optimal N rate to maximize RWST and profits was 0 to 45 kg N·ha⁻¹ and confirmed their negative relationship to applied N. Optical sensor readings correlated negatively with RWST across the majority (>60%) of cultivars tested in mid-August and September. Across all cultivars, the regression model of optical sensors to predict RWST at early harvest was strongest (R² = 0.48 for SPAD; 0.24 for GreenSeeker) when readings were taken in early September. Although future research to refine this relationship is needed, we recommend the use of optical sensors, particularly the SPAD meter, in early September to guide harvest selection to maximize RWST.

Horticultural systems, specifically vegetable production systems, are considered intensive agricultural systems as they are characterized by high nitrogen (N) fertilizer application rate, frequent tillage, and irrigation operations. Accordingly, horticultural production in temperate climates is prone to N losses — mainly during post-harvest (during fall and winter) or pre-plant (spring) periods — such as N₂O emissions and nitrate leaching. The risk for N losses is linked to low crop N use efficiency (NUE) combined with a narrow C:N and high N content of crop residues. Here we reviewed the studies conducted in Canada and similar climates to better understand the risk of N₂O emission and potential agronomic management strategies to reduce N₂O emissions from horticultural systems. Current knowledge on N₂O emissions from horticultural systems indicate that increasing crop NUE, modifying the amount, type, time, and rate of N fertilizer inputs, and adopting cover crops in crop rotations are some of the effective approaches to decrease N₂O emissions. However, there is uncertainty related to the efficiency of the existing N₂O mitigation strategies due to the complex interactions between the factors (soil characteristics, type of plant species, climatic conditions, and soil microbial activity) responsible for N₂O production from soil. Little research on N₂O emissions from Canadian horticultural systems limits our ability to understand and manage the soil N₂O production processes to mitigate the risk of N₂O emissions. Thus, continuing to expand this line of research will help to advance the sustainability of Canadian horticultural cropping systems.

Cover crops have the potential to immobilize nitrogen (N) that would otherwise be lost before or after the main crop production, leading to improved N management. However, information on how cover crops influence N management in intensive vegetable cropping systems is scarce. This study aimed to determine how an overwintering rye cover crop impacts crop yield and N cycling, for three common prairie vegetable crops. From 2017 to 2019, a broccoli – sweet corn – root crop sequence was tested (in which all crops of rotation were present each year), with each crop type receiving five N fertilizer treatments, ranging from 0 to 300 kg N·ha⁻¹. After harvest each year, sub-plots were established with vs. without a rye cover crop, and the effect on vegetable yield, soil inorganic N, and N use efficiency (NUE) was followed into the subsequent growing season. In most cases, the cover crop increased vegetable crop productivity and N content in the subsequent growing season. The cover crop also lowered soil inorganic N levels at vegetable planting but increased levels at harvest. Vegetable crop NUE indices were frequently improved with vs. without the cover crop. As for the N fertilizer response, increasing N fertilizer rate did not continually increase vegetable crop productivity and N content. Higher N fertilizer rates increased soil inorganic N levels at vegetable planting and harvest, and often lowered vegetable crop NUE indices. These results demonstrate the importance of adjusting soil N levels to better align with crop needs — and that including a rye cover crop in the vegetable rotation is one method of doing so.

Hexanal slows down the ripening process in fresh produce by inhibiting the activity of phospholipase D, thereby increasing shelf life. This study focused on comparing the single time exposure and continuous exposure of post-harvest Anjou and Bartlett pears to hexanal by dipping or fumigating them to enhance their shelf life. Continuous exposure of hexanal was achieved by developing a hexanal encapsulated fiber (HEF), which releases hexanal vapor due to the increased humidity (96 ± 2% RH) in the container headspace as a result of respiration. The fruits were stored in cold storage (0 ± 2 °C) as well as at normal room temperature (20 ± 2 °C) and their storage capacity was compared between the treatments. Fruit parameters such as physiological loss of weight (PLW), firmness, and total soluble solids (TSS) showed only minor differences between hexanal treated and untreated fruits. Between the two varieties, Anjou exhibited slightly higher values than Bartlett. However, when the fruits are visually evaluated, the main aspect of consumer preference, HEF-treated fruits had a better appeal in both varieties and in both conditions. Bartlett responded better than Anjou even in cold storage conditions, suggesting that there are varietal differences in their response to hexanal. Both hexanal treatments helped color retention and reduced fungal infection under the storage conditions tested.

Summer fruitlet thinning is implemented as a routine orchard practice to produce apple fruits with good quality. However, its impacts on the dynamics of fruit quality metrics during the growing season and in the postharvest storage, remain unclear. In this study, summer hand thinning on fruitlets of Ambrosia™ apple (Malus × domestica Borkh.) was conducted on two dwarfing rootstocks, Malling 9 (M.9) and Budagovsky (B.9), in an organic orchard and a conventional orchard under the semi-arid climate in Similkameen Valley, BC. Adequate thinning [(AT) in which 70% of fruitlets were removed] and light thinning [(LT) in which 30% of fruitlets were removed] were implemented in randomized plots in 8 wk after full bloom. Fruit development and dry matter content (DMC) were then monitored during the growing season; fruit quality was subsequently evaluated at harvest and after 4 mo of air storage at 0.5 °C. Relative to LT, AT enhanced fruit quality attributes in DMC, surface blush coverage and intensity, and soluble solids content (SSC) at harvest. The apples with higher DMC under AT also possessed higher compositional quality and lower incidences of fruit disorder in the postharvest stage. This study suggests that summer fruitlet thinning of Ambrosia apples can have significant impacts on fruit composition during subsequent on-tree fruit development, on the onset of ripening and eventually on the retention of quality and minimization of disorders over 4 mo of cold air storage. This effect is found for organic orchard (OG) and conventional orchard (CV) production systems and with both dwarfing rootstocks.

Haskap (Lonicera caerulea L.) is a relatively new berry crop in North America, and little research exists regarding its postharvest storage characteristics or storage life. Postharvest changes in berry quality, and principal factors limiting storage life at 1.1 °C and 95% relative humidity, were evaluated up to 14 days for three cultivars in 2019 and up to 28 days for six cultivars in 2020. Containerized berries were periodically assessed for soluble solids content (SSC), skin rupture force (SRF) (both 2019 and 2020) and flesh firmness, titratable acidity (TA), and Brix/acid ratio (B/A) (2020 only). External appearance was also evaluated both years, revealing berry shrivel as the primary factor negatively impacting visual appeal, followed distantly by low incidence of spoilage later in storage. All cultivars exhibited relatively constant postharvest SSC and decreasing SRF, flesh firmness, and TA (resulting in increasing B/A ratio). Postharvest quality differed slightly between years; relative SRF was consistent among cultivars while SSC was not. Some cultivars had a portion of shriveled berries at harvest, pointing to a need for cultivar-specific harvest indices. Mean days to slight shrivel for individual berries varied among cultivars evaluated, ranging from 7.5–21.9 d postharvest, with mean weight loss ranging from 1.2%–1.6% at this stage. Combined with group marketability estimates — set at a threshold of 10% severely shriveled berries — we estimate a storage life of 7–10 d for fresh haskaps. Additional research is needed to delineate maturation physiology and optimize harvest timing.