ASHS 2024 Conference

Phosphate Solubilizing Bacteria: Leveraging The Soilless Substrate For Improved Phosphorus Nutrition In Controlled Environment Agriculture. - Michelle Jones
Phosphate Solubilizing Bacteria Isolated From Greenhouse Ornamentals Solubilize Phosphate In Vitro And Ameliorate P Deficiency Symptoms In Marigold ‘Durango Yellow’ Fertilized With Calcium Phosphate. - Juan Quijia Pillajo
Activated Aluminum Amended Substrates Reduce Phosphorus Leaching in Floriculture Production - Damon Abdi
Iron-coated Sand as a Sustainable Substrate Amendment for Nutrient Management of Containerized Floriculture Crops - Savannah Mead
Phosphorous Restriction Suppresses Growth of Containerized Coneflower - Garrett Owen
Investigating Synergistic Effects of Biostimulants and Biochar on Water Use Efficiency for Containerized Celosia (Argentea cristata) and Gomphrena (Gomphrena globose) Production - Lilin Chen
Effects of Reduced Water Usage During Production on Economic Value, Growth, And Quality of Flowering Indoor Plants - Kaitlin Hopkins

Phosphorus (P) is an essential macronutrient with low availability for plant uptake. The availability of P is reduced by the formation of insoluble complexes with calcium (Ca) and iron (Fe). Phosphorus solubilizing bacteria (PSB) can enhance P uptake by producing organic acids that acidify the rhizosphere and breakdown the insoluble P compounds. The goal of this research is to identify PSB that can increase P uptake efficiency in soilless production systems. A collection of bacteria isolated from the rhizosphere of greenhouse grown ornamentals was used to identify PSB using both in vitro and in planta evaluations. A malachite green assay optimized for 96-well plates was used to screen 1,056 bacterial isolates for the ability to solubilize phosphorus from both calcium phosphate and iron phosphate. This in vitro assay identified 14 and 24 PSB that solubilized 25% or more of the P from Ca2(PO4)3 and FePO4·2H20, respectively. There was no overlap between the PSB that solubilized Ca2(PO4)3 and those that solubilized FePO4. In planta evaluations were conducted in Marigold ‘Durango Yellow’ (Tagetes patula) and Tomato ‘Bush Beefsteak’ (Solanum lycopersicum) grown in a peat-based substrate (pH=7) and inoculated with individual PSB as a media drench (20 mL; OD595=0.1). Digital phenotyping with the TraitFinder (Phenospex) was used to quantify growth promotion (digital biomass and bloom area), and the severity of P deficiency symptoms [Green Leaf Index (GLI), normalized difference vegetation index (NDVI), Normalized Pigment Chlorophyll Ratio Index (NPCI), and Plant Senescence Reflectance Index (PSRI)]. Only seven FePO4·2H20 solubilizers (Fe-PSB) and six Ca2(PO4)3 solubilizers (Ca-PSB) performed better than the control in at least one of the evaluated parameters. A validation experiment was conducted to confirm the beneficial activity of the seven Fe-PSB (C2F9, C3A8, C11G1, C8D10, C6E7, C3G9, and C3F10) and the six Ca-PSB (C4A1, C2G6, B3A7, C11A5, C4B6, C12F4, and C6H6). The validation experiments were conducted with Marigold ‘Durango Yellow’ and Tomato ‘Early girl’ grown in a peat-based substrate (pH=7) and inoculated with individual PSB as a media drench (20 mL; OD595=0.1). Bacillus megaterium (C3F10), Pseudomonas sp. (C6E7), and two strains of Pantoea rwandensis (C3A8 and C8D10) showed a beneficial response when applied to plants fertilized with FePO4·2H20. Only, Enterobacter soli C4A1 showed a beneficial response when applied to plants fertilized with Ca2(PO4)3. The malachite-green assay and digital phenotyping are suitable tools for high-throughput identification of PSB that can be used to improve phosphorus nutrition in soilless culture systems.

Phosphorus (P) is an essential macronutrient absorbed by plants as orthophosphate (PO4). P availability depends on the pH of the substrate. At high pH, P forms insoluble compounds like Ca3(PO4)2 which is unavailable for plant uptake. Phosphate solubilizing bacteria (PSB) are plant-associated microorganisms that can break down Ca3(PO4)2 by secreting organic acids. PSB have been primarily evaluated as inoculum for crops grown in soil to improve P availability. However, less is known about the application of PSB in ornamentals grown in soilless substrates. Our goal was to identify PSB from a collection of bacteria isolated from the rhizosphere of greenhouse ornamentals. First, the collection was screened in vitro for the bacterial capacity to reduce pH of the media using the bromophenol-blue color assay. Thirty-five isolates were identified to reduce media pH, and their P solubilization capacity was quantified using ion chromatography. Fourteen isolates with the highest P solubilization were selected for whole-genome sequencing, but only two bacterial isolates (C2B11 and C8D10) were advanced to the in-planta evaluation using Marigold (Tagetes patula) 'Durango Yellow' grown in a peat-based substrate (pH = 7). Plants were irrigated with 100 mg·L-1 N from a 15N-0P-15K fertilizer, and P was supplemented weekly as Ca3(PO4)2 via substrate drench applications. Lalrise Vita (Lallemand Plant Care) and Bacillus velezensis (the active ingredient in Lalrise Vita) were included as positive controls. Plant phenotyping was conducted using the TraitFinder automatic system (Phenospex). TraitFinder assessment parameters included digital biomass, bloom area, Green Leaf Index (GLI), Normalized Pigment Chlorophyll Ratio Index (NPCI), and Plant Senescence Reflectance Index (PSRI). Lalrise Vita performed better than the control in all the parameters evaluated. B. velezensis increased bloom area and showed higher GLI and lower NPCI than the control. Pantoea sp. C2B11 significantly increased digital biomass, bloom area, and GLI. Pantoea sp. C8D10 only showed an increase in GLI values. Both C2B11 and C8D10 possess various genes involved in gluconic acid production. We identified two PSB that solubilize P in vitro, promote growth and bloom area, and improve canopy health (high GLI or low NPCI) in marigold plants fertilized with Ca3(PO4)2. Our next step is to validate the growth-promoting capacity of the identified PSB in other ornamentals. PSB can contribute to improving phosphorus nutrition and fertilizer use efficiency in greenhouse ornamental production.

The use of water-soluble fertilizers in floricultural production provides readily available nutrients to sustain short-term crop production; however, nutrients such as phosphorus are poorly retained in typical peat substrates. Activated aluminum is an amendment that has demonstrated success in binding phosphorus within substrates, reducing the amount of phosphorus that is leached from the container. This research investigated the production of Tagetes in peat-based substrates amended with or without activated aluminum and provided four different phosphorus fertilizer regimens. The fertilizer regimens encompassed a nitrogen, phosphorus, and potassium liquid blend applied weekly; however, phosphorus was only included for 0, 2, 4, or 6 weeks in total over the duration of the study. Growth of Tagetes was effectively similar, and leachate analysis provided insights that can be applied towards more efficient production methods. In this research, utilizing activated aluminum resulted in less phosphorus loss in container leachate than unamended substrates. The potential to decrease applied phosphorus during floricultural production can similarly be achieved when using substrates amended with activated aluminum. This presentation will decipher the dynamics of the movement of phosphorus and other anions of interest that may be relevant to sustainable floriculture production.

As natural resources dwindle, sustainable alternatives to current fertilization methods are essential for environmental and economic progress. Acid mine drainage (AMD) and phosphorus from fertilizer runoff are significant sources of water pollution in the Appalachian region of the United States. Horticultural producers are faced with rising prices of phosphate fertilizers, putting the industry in a tenuous position: reducing these costly inputs to minimize water pollution but, in turn, diminishing product quality. AMD-based iron-coated sand is a novel phosphate sorbent that can potentially ameliorate AMD and prevent further phosphate pollution. This technology can cut growers’ input costs and slow the consumption of finite phosphate resources. This study aimed to determine the viability of iron-coated sand as a substrate amendment for reducing phosphate leaching and enhancing growth, flowering, and phosphorus uptake of floriculture crops during and after production. The ideal sand-to-potting mix ratio was determined based on pansies, petunias, and chrysanthemums' growth, flowering, and leachate content. The rate of applied phosphate and P-saturation of sand were determined from growth, flowering, and leachate data of chrysanthemum during production. Finally, the effects of the coated sand were examined on petunia and chrysanthemum growth, flowering, mineral content, and leachate composition over time in production and post-production environments. Twenty percent P-saturated iron-coated sand with low to moderate rates of applied phosphorus reduces leached phosphate with no deleterious, and usually positive, effects on the performance of floriculture crops during and after production. Iron-coated sand as a substrate amendment in container production of ornamentals has tremendous potential for advancing environmental and economic sustainability in the horticultural industry.

Containerized coneflower (Echinacea sp.) production in greenhouses and nurseries often relies on commercial fertilizers, such as 20 nitrogen (N)–4.4 phosphorous (P)–16.6 potassium (K), applied at 100 to 200 mg·L−1 N; however, increasing N concentrations proportionately increase phosphorous pentoxide (P2O5) and thus, elemental P concentrations. As such, the recommended N fertilization supplies P concentrations of 21.8 to 43.6 mg·L−1 P, exceeding plant requirements and potentially leading to excessive stem elongation and P runoff, posing ecological risks. Therefore, the objective of this study was to evaluate the effects of P concentrations on the growth, ornamental value, and tissue mineral nutrient concentrations of coneflower (E. × hybrida Sombrero® Granada Gold ‘Balsomold’). A custom soilless substrate was formulated with (by vol.) 55% aged pine bark, 35% sphagnum peatmoss, and 10% perlite, and amended with 0.6 kg·m−3 wetting agent and 3.9 kg·m−3 dolomitic limestone to achieve a final pH of ≈5.6 to 5.8. Young plants of coneflower were individually transplanted into 16.5-cm-diameter (1.7 L) containers filled with the custom soilless substrate. Upon transplanting and throughout the experiment, plants were irrigated with nutrition solutions formulated from technical grade salts providing 0, 2.5, 5, 7.5, 10, 15, 20, or 30 mg·L–1 P. Plants were grown in a glass-glazed greenhouse at 20 °C under ambient daylight supplemented with a photosynthetic photo flux density of ≈120 µmol·m–2·s–1 delivered from light-emitting diode lamps from 0600 to 2200 hr (16-h photoperiod) to achieve a daily light integral of 14 mol·m–2·d–1. At anthesis (≈69 d after transplant), data were collected. In general, plant height, plant diameter, and shoot and root dry weights were significantly influenced by P concentrations, although to different magnitudes. Quadratic plateau models demonstrated plant height, plant diameter, and shoot dry weight were maximized at 52.7 cm, 36.5 cm, and 27.2 g, respectively, with P concentrations of 18.3, 15.9, and 23.4 mg·L−1 P, respectively. Root dry weight demonstrated a positive linear correlation with increasing P concentration where roots were 74% (3.3 g) larger at a P concentration of 30 than 0 mg·L−1 P. Concentrations of ≤ 7.5 mg·L−1 P resulted low (≤ 0.2% P) leaf tissue P concentrations and ≤ 2.5 mg·L−1 P resulted in low-quality plants with incipient symptoms of P deficiency. Collectively, these results indicate that a narrow range of P concentrations may be used to control coneflower growth and mitigate P pollution.

Given the escalating demands for water and the accompanying scarcity, enhancing water use efficiency (WUE) in horticultural practices has become imperative. Research has revealed that both biochar (BC) and seaweed extract biostimulants (BS) significantly enhanced WUE in plant growth, presenting promising avenues for sustainable agricultural advancement. This study aimed to investigate the synergistic effect of BC and BS on WUE for celosia (Argentea cristata) and gomphrena (Gomphrena globose) production. Three factors were included in this experiment including 1) mixed hardwood biochar blended with commerical substrate mixes (CS) at 0%, 10%, 15%, and 25% 2) 60% or 80% irrigation and 3) 0 or 5 mL BS(seaweed extract). The physical properties of substrate, including container capacity (CC), total porosity (TP), air space (AS), bulk density (BD), and water holding capacity (WHC), and chemical properties including leachate pH and electrical conductivity (EC) were measured. Plant growth parameters including growth index (GI) and leave greenness (indicated with SPAD value), biomass, and numbers of flowers were measured biweekly. Photosynthesis rate, transpiration rate, and stomatal conductance rate were measured at 6, 7, 8 WAT. The results showed that BC rates had significant effects on CC, and BD, but no effects on either TP, AS or WHC. Celosia plants grown in the 25% BC mix treated with 5mL BS at 80% irrigation had significantly higher biomass and WUE, and both plants in the same mix (25

The objective of this study was to investigate the effects of soil moisture content during greenhouse production of selected floriculture crops. Over the course of several seasons, multiple flowering species were investigated, including Euphorbia milii, Cyclamen persicum, and Begonia x tuberhybrida. Plant quality characteristics were evaluated both during the production timeframe, and after a simulated shipping and retail setting. Treatments included two soil moisture content levels (20% and 40%), which was monitored by soil moisture probes. Production timelines varied, due to the differences in species. Once the predetermined production weeks were concluded the plant went into simulated shipping and retail environment. Qualities such as growth index (GI), leaf greenness (SPAD), Leaf thickness, petiole thickness, irrigation events, and irrigation amount were measured weekly. Flower number and foliage fresh /dry weights were gathered after the two week simulated retail period. Results varied depending on the species. In all species the 20% group had less watering events, which equates to producer savings in fertigation inputs as well as labor. All species had reduced canopy size in the 20% treatment, which could equate to bench space conservation. Some of the plant quality characteristics depending on the species had similar results after simulated retail. This equates to the idea that producers could reduce water application events and volumes and generate an equal quality plant compared to the traditional watering methods, while also saving on input and labor costs.

Postharvest Performance of Tomato Fruit at Shelf-life Conditions in Relation to Fertilization Rate During Plant Production and Fruit Ripening Stage at Harvest - Sotirios Tasioulas
Identification of NAC Transcription Factors Involved in the Ripening and Senescence of Pepper (Capsicum annuum L.) Fruit - Kyeonglim Min
Comparative Analysis of Volatile Organic Compounds of Eight Microgreens in the Brassicaceae Family - Jinhe Bai
Nutritional Quality and Shelf-Life of “Living Lettuce” Through 28 Days of Cold Storage - Marlee Trandel Hayse
Comparing the Postharvest Phytonutrient Content of Red and Green Butterhead Lettuce Cultivars - Marlee Trandel Hayse
Production System Alters Phytonutrient Content of ‘Skyphos’ Butterhead Lettuce - Marlee Trandel Hayse
Improving Postharvest Storage and Late-Season Production of Caladium Tubers in Florida Through Chemical Treatments - Gasselle Cordova
Impact of Storage Environment on Dormancy Progression and Microbiome of Potato Tubers - Munevver Dogramaci
Strawberry Anthocyanins, Extraction, Assessments and Storage - Toktam Taghavi
Isolation of Pathogenic Strain of Trichoderma atroviride from Symptomless, Disease-Free Sweetpotato (Ipomoea batatas L.) Storage Roots - Richard Noel Torres

This study investigates how the ripening stage at harvest and fertilization rate impact tomato fruit quality. Tomato plants (cv. HM1823) were grown during the Fall 2023 season under four levels of fertilization (75%, 100%, 125%, and 150% of the recommended UF/IFAS rate, which is 200 lb/A nitrogen and potassium). Fruit were harvested at four distinct ripening stages: mature green (MG), turning (T), pink (P), and red (R), as assessed visually and stored at 25°C. Color, firmness, soluble solids content (SSC), pH, and titratable acidity (TA) were measured every 4 days until 12 or 16 days (for MG fruit). According to the analysis of variance, all factors (fertilization rate-FR, ripening stage at harvest- RS and shelf life period- SL), as well as the interaction RSSL significantly (P

Pepper (Capsicum annuum L.) as a non-climacteric fruit is usually harvested at either mature green or ripe stage, and fruit quality including texture, color, and nutritive values is different according to the fruit developmental stages. Understanding molecular mechanisms of fruit ripening and senescence processes is crucial to control the fruit quality and reduce the postharvest loss. This study was aimed to identify NAC transcription factors (TFs) involved in the ripening and senescence of pepper fruit by analyzing gene expressions and protein-protein interactions. To identify NAC genes related to the ripening, transcript levels of total 104 NAC TFs were investigated using publicly available transcriptome data. Among them, transcript levels of 8 genes significantly increased during the ripening and senescence. Their phylogenetic analysis also showed that they are closely associated with NAC TFs which play a role in ripening or senescence in other crop species. Among them, 4 genes showing abundant transcript levels at the ripening stage were selected, including CaNAC14, 45, 84, and 92, to further investigate their roles. In pepper (C. annuum var. ‘Gyeonggiyangpyeiong’) fruit, their expressions clearly increased during the ripening or induced by exogenous ABA, the major phytohormone regulating non-climacteric fruit ripening. To reveal a relationship between the CaNACs and ABA signaling, protein-protein interactions between the CaNACs and ABA receptors were analyzed through yeast- two-hybrid and bimolecular-fluorescence complementation assays. Among them, CaNAC92 and CaPYL12, the ABA receptor, interacted each other in a nucleus with an ABA-dependent manner. This result indicated that their interaction may affect the ABA signaling or the transcriptional regulation during the ripening. We identified CaNAC TFs involved in the pepper fruit ripening and suggested CaNAC92 as a putative molecule functioning in the ripening. These findings will provide genetic information to control the ripening and to improve pepper fruit quality.

This study investigates the volatile organic compounds (VOCs) of eight microgreens in the Brassicaceae family, known for their robust flavors and potential health benefits, including detoxification properties and anti-cancer effects. The microgreens analyzed included five Brassica species—B. juncea (mustard), B. napus (kale), B. rapa (mizuna), B. oleracea L. var. capitata (red cabbage), and B. oleracea L. var. italica (broccoli)—as well as Eruca sativa (arugula), Lepidium sativum (cress), and Raphanus sativus (radish). The above-ground plant tissues were homogenized in saturated salt water and the VOCs were examined using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GCMS). A total of 117 VOCs were identified across all tested species, with individual species VOC counts ranging from 42 to 67. Radish showed the highest total ion current at 676 million (mTIC), with other species varying down to 190 mTIC in arugula. Notably, sulfur and/or nitrogen-containing compounds (SCCs and/or NCCs) constituted over 90% of the total VOCs collected from all species, with Brassica species containing more than 96% SCCs and 93% NCCs. Conversely, radish and arugula had less than 88% NCCs, and cress contained only 66% SCCs. Dominant compounds were primarily isothiocyanates, with significant variability in major VOCs across different species. For instance, allyl isothiocyanate was prevalent in mustard, mizuna, and red cabbage; 4-isothiocyanato-1-butene in kale and mizuna; isothiocyanatomethyl-benzene in cress; 1-isothiocyanato-4-(methylthio)-butane in arugula and broccoli; and (E)-4-isothiocyanato-1-(methylthio)-1-butene in radish. The reduced SCCs in cress were attributed to the higher presence of benzyl nitrile and benzyl isocyanate, while the lower NCCs in radish were linked to increased levels of dimethyl disulfide and dimethyl trisulfide. This diversity in SCCs and NCCs contributes to the varied volatile flavors and potential health benefits of these microgreens.

Lettuce (Lactuca sativa) is cultivated in controlled environment agriculture via vertical production or hydroponic well systems. To extend shelf-life, growers harvest “living lettuce” by keeping roots intact, but there is limited data supporting this harvesting technique. The objective of this study was to assess the use of clamshell and root treatments on the shelf-life and nutritional quality of lettuce. Treatments included storage either inside or outside of plastic clamshells and with roots removed or intact. Lettuce was stored for 28 days at 4 oC, 85% relative humidity. Percent weight loss (%weight loss), visual ratings (1 to 5 scale, 1 = poor and 5 = excellent), and colorimeter analysis (L*, a*, b*, c*, hue angle) were measured every 3 days. Total assays of chlorophyll, carotenoids, anthocyanins, flavonoids and phenolic activity were analyzed via UV VIS spectrophotometry every 7 days throughout storage. Few differences were seen in root treatment. As days in storage progressed, %weight loss progressed to 16.9%. Closed clamshells decreased %weight loss (5.5%) compared to open (18.1%). Visual ratings of yellowing/nutrient deficiency, relative greenness, wilt/head looseness, and salability decreased through storage. Lettuce stored in closed clamshells decreased %weight loss by 12% and delayed wilt/head looseness by 11 days. Similarly, lettuce stored in closed clamshells with roots were salable until 18 days in storage, while open clamshells were no longer salable after 7 days. Short root length (~4 cm) may be the dominant factor for the lack of significance as previous research suggested harvesting “living lettuce” with 9 cm roots increased storage and quality. Color data differed, and lettuce stored in closed clamshells with roots had more intense red color a* (-3.7 vs. -2.7), blue color b* (12.6 vs 10.1), and were purer in color c* (13.3 vs. 10.5) compared to open clamshells with roots. No differences were seen in total anthocyanin (mg/L), total chlorophyll (g/g) or total carotenoid (g/g) content in clamshell or root treatment (p > 0.05). Through 14 days of storage, total anthocyanins degraded by 7.55 mg/L (Day 0 = 10.78 vs. Day 14 = 3.22), while no loss of total chlorophyll (9204.84 g/g) or total carotenoids (1947.25 g/g) were seen. Anthocyanins are water soluble pigments and with increased weight/water loss, anthocyanins solubilize leading to degradation. Chlorophylls and carotenoids were not lost, potentially due to low enzyme activity of chlorophyllase. This experiment indicates consumers should eat lettuce within 7-10 days of harvest for highest nutritional and postharvest quality.

Lettuce is a popular leafy vegetable that can play an important role in human nutrition and diets with regular consumption. Lettuce cultivars can vary considerably in their postharvest nutritional composition. It is critically important to determine which lettuce cultivars have the highest nutritional quality to allow growers to select those that are best for their market. The objectives of this experiment were twofold, to determine differences in the phytonutrient content of two butterhead lettuce cultivars, ‘Nancy’ (green butterhead) and ‘Skyphos’ (red butterhead), and if leaf location within the head (lower or mid leaves) differs in nutritional composition. The experiment was conducted in the spring of 2023 in a high tunnel, and setup as a completely randomized design with 4 replications. At horticultural maturity (40 days after germination), the lower and mid leaves were harvested. Lettuce samples were frozen and shipped to Auburn University where samples were assayed for total chlorophyll, carotenoids, anthocyanins, flavonoids, phenolics and antioxidant activity via UV VIS spectrophotometry. Carotenoids of violaxanthin, neoxanthin, lutein and -carotene were quantitated by UPLC/MS. The interaction of leaf location*cultivar (P < 0.05) indicated that the lower leaves of ‘Skyphos’ lettuce had the highest total anthocyanin content at 2.94 mg/L compared to ‘Nancy’ at 0.05 mg/L, respectively. No other differences (P > 0.05) were detected between the cultivars. Sample location differed in total carotenoids (mg/g) and total chlorophyll (mg/g) with the lower leaves having the highest nutritional composition at 1380.18 and 5973.58 mg/g, respectively compared to the mid leaves (509.02 and 1684.42 mg/g, respectively). Chlorophyll a (4399.67 mg/g) and b (1573.90 mg/g) was also highest in the lower leaves of both cultivars compared to the mid leaves. Our results indicate that both butterhead lettuce cultivar and leaf location strongly impacts human health. ‘Skyphos’, a red butterhead lettuce, had the high highest total anthocyanin content in the lower leaves. Anthocyanins are critical phytochemicals known for many health promoting properties such as free radical scavenging, and anti-cancer and anti-diabetic properties. This experiment also indicated the lower leaves of both cultivars had the highest amount of total chlorophyll and carotenoids. The lower leaves of red butterhead lettuces, such as ‘Skyphos’, should be eaten to obtain the highest nutrition for their diet.

Lettuce is one of the most widely consumed vegetables in the world and can provide various health benefits to consumers. The type of production system, such as high tunnel, green roof or open field environments, can influence the nutritional composition of lettuce. To determine the extent of phytonutrient content change, ‘Skyphos’ lettuce was grown in these various production environments to compare phytonutrient content at harvest. The production experiment was conducted at Southern Illinois University-Carbondale and set up with three treatment locations and four replications. Two production systems used organic fertility practices (high tunnel and green roof), while the field production system used conventional fertilizers. At horticultural maturity (40 days after germination), the lower and mid leaves were harvested to determine phytonutrient content. Lettuce samples were frozen and shipped to Auburn University where samples were assayed for total chlorophyll, carotenoids, anthocyanins, flavonoids, phenolics and antioxidant activity via UV VIS spectrophotometry. Carotenoids of violaxanthin, neoxanthin, lutein and b-carotene were quantitated by UPLC/MS. The interaction of production system*leaf sampling location differed (P < 0.05) in total anthocyanins, total carotenoids and total chlorophyll. Total anthocyanins were highest in the lower leaves of ‘Skyphos’ lettuce cultivated on the green roof at 3.57 mg/L. In comparison, total carotenoids, total chlorophyll and chlorophyll a were highest in the lower leaves of lettuce cultivated in the high tunnel at 1316.48, 6093.45 and 4401. 97 mg/g, respectively. Cultivating lettuce in the high tunnel provided the highest Chlorophyll b content (1638.37 mg/g) compared to the field (888.80 mg/g) or green roof (893.43 mg/g). The phytonutrient content of lettuce can be influenced by location, temperature, soil type, humidity and UV radiation. The green roof increased total anthocyanin content which may be due to the higher temperatures and irradiation levels on compared to the field or high tunnel. Total Chlorophyll and carotenoid content was increased in the high tunnel likely due to increases of UV-A and UV-B exposure from the poly film leading to an increase in photosystem response. This experiment suggests the specific phytonutrient content (e.g., anthocyanin or carotenoids) in a red lettuce like ‘Skyphos’ differs based on production system and can be used in market development to increase consumer consumption by highlighting the specific phytonutrients highest in each production system.

Florida is home to the largest caladium production in the world, supplying essentially all the global caladium tuber demand. These plants are famous for their vibrant leaf colors and patterns and are asexually propagated through tubers. Following plant development, tubers are harvested and stored for a few months before being forced from March to September for potted plant production and direct landscape planting. During extended postharvest storage, caladium tubers risk severe weight loss, tissue decay, and Fusarium tuber rot. The current storage practices under ambient conditions with high temperatures and high relative humidity exacerbate weight loss and tuber rot. The challenges of long-term tuber storage make it difficult to produce pot caladium plants for winter holidays, including Thanksgiving, Christmas, and New Year. These challenges also affect the commercialization of tubers in the Southern Hemisphere during the summer. Opening these marketing opportunities can allow growers to extend and increase their production. Additionally, identifying caladium tubers suitable for late-season production will give Florida growers a competitive advantage. To identify caladium varieties with long-term tuber storage potential and late-season production, 12 varieties were evaluated to target Thanksgiving and Valentine’s Day. No.1-sized tubers were potted in 5-inch containers and grown in a greenhouse. For each variety, 10 tubers were monitored for sprouting and leaf expansion and later evaluated for plant quality using a rating scale from 1 to 5. Potted tubers from all cultivars achieved suitable market quality standards when targeting Thanksgiving, with the higher ratings obtained by cultivars ‘Splash of Wine’, ‘Classic Pink’, and ‘Lemon Blush’. The higher number of leaves and height were obtained by cultivars ‘Classic Pink’, ‘Desert Sunset’, and ‘White Wonder’, and ‘Party Punch’, ‘Ballet Slipper’, and ‘Classic Pink’, respectively. For Valentine’s Day, despite sprouting decreasing, cultivars ‘Splash of Wine’, ‘Hot 2 Trot’, ‘Desert Sunset’, ‘Party Punch’, ‘Classic Pink’, ‘White Wonder’, and ‘Lemon Blush’ reached suitable market quality standards. Overall, the number of leaves and height decreased compared to plants targeting Thanksgiving, however, cultivars with a more desirable number of leaves were ‘Classic Pink’ and ‘Lemon Blush’ whereas cultivars with higher height were ‘Party Punch’ and ‘Ballet Slipper’. Identifying cultivars suitable for late-season production will allow growers to expand their commercialization window for major holidays and to supply tuber demand to the Southern Hemisphere.

Preservation of nutritional and market qualities of potato tubers during postharvest storage is essential for optimum economic return. Protecting tubers from unintended sprouting during storage is one of the major postharvest challenges that potato growers and stakeholders encounter. Storage environment, particularly storage temperature, significantly impacts dormancy progression and sprouting and effect overall marketability. Potato tubers carry significant amount of microbiome in different tissues of tubers from field to storage, which might contribute to overall storage qualities. However, how storage temperature impacts overall potato tuber microbiome and how changes in microbiome influence tuber dormancy are largely unknown. Therefore, the primary objective of this study was to investigate the impact of different storage temperatures on tuber microbiome and monitor the dormancy progression and sprout growth during long-term storage. Certified seed tubers of Russet Burbank were cured after harvest following industry practices. Then, one subset of tubers was stored at constant 8°C, and a second subset was stored at constant 21°C. Three types of tuber tissues (primary meristem, secondary meristem, and tuber flesh) were collected after 4, 8, 12, 17, and 24 weeks of storage for microbiome profiling and sugar and protein analysis. Additionally, a third subset was generated by moving tubers from 8°C to 21°C three days before sampling time of 8, 12, and 17 weeks. Tuber dormancy progression was monitored using additional subsets for each storage condition. As expected, the subset of tubers stored at 8°C had delayed sprouting compare to 21°C, and rapid sprout growth was observed when tubers were moved from 8°C to 21°C. Increase in reducing sugar content was observed in meristem tissues, while it decreased in tuber flesh with progression of storage duration. Interestingly, higher protein content was determined in secondary meristem tissues compare to primary meristems and tuber flesh. Overall, greater bacterial and fungal diversity and abundance were observed in meristem tissues when compared to tuber flesh. Additionally, storage temperatures, storage time, and tuber tissue types significantly impacted tuber microbial profile. In tuber tissues, Ascomycota and Basidiomycota were predominant fungal phyla, while Actinobacteria, Proteobacteria, and Cyanobacteria were the predominant bacterial phyla. Our results suggested that storage temperature and storage duration significantly impact both dormancy progression and tuber microbiome and subsequently contribute to postharvest qualities of potato tubers.

The anthocyanin pigments have antioxidant activities and play critical roles in plant and human health. They are abundant in flowers, vegetables, and fruits and are soluble in water, methanol, and nonpolar solvents such as chloroform. Extracting stable pigments with higher concentrations has been the research community's and industries' goal. Spectrophotometric methods can easily measure the total anthocyanin content. Other complex and more expensive methods, such as high-pressure liquid chromatography and ultrasound-assisted methods, are also available to identify and quantify the anthocyanin pigment. Strawberry color affects the appearance, fruit quality after harvest, and consumers' decision-making process. A large group of factors, such as sample type, temperature, pH, solvent type, and the ratio of its components, affect strawberry anthocyanin yield. We studied the effect of some of these variables on the anthocyanin yield, profile, and color of strawberries. Extraction solvents significantly changed the anthocyanin yield. The results suggest that acidified chloroform-methanol extracted the highest anthocyanin content compared to water-based solvents. Methanol-water-based solvents also performed better than water alone. Processing time (incubation time) was lowest in the pH differential method; however, the haze produced in this method may interfere with the spectrophotometry. Chloroform-methanol solvent with higher pH extracted pelargonidin as the main anthocyanin, and methanol and water-based solvents extracted delphinidin in UHPLC. Chloroform extracts reduced the redness and increased the extracts' brightness mainly due to higher pelargonidin content. Less redness and increased brightness indicated some level of color degradation of the extracts after storage for 48h at 4 °C.

Many fungal endophytes have the ability to promote plant growth, as well as increase the host plant’s tolerance to abiotic and biotic stresses. Most endophytic species of Trichoderma are well known biocontrol agents and have been used to control diseases caused by phytopathogens of the genera Rhizoctonia, Fusarium, and Phytophthora. However, our recent research has isolated a strain of Trichoderma from sweetpotato storage roots purchased from a local farm, which was shown to develop root rot symptoms. Therefore, the objective of this project was to evaluate this isolate, especially for its potentially pathogenic nature. In the laboratory, the ITS region of the isolate was amplified, and gene sequencing placed it to T. atroviride with 99% homology. However, T. atroviride has never been identified as a disease-causing agent for sweetpotato in literature so far. Pathogenicity test was carried out accordingly, by inoculating this isolate onto healthy, symptomless sweetpotato storage roots. Two weeks post-inoculation, the storage roots were cut in half to reveal necrotic lesion development between 1.7 and 2.1cm in diameter based on three replications. The necrotic tissue was sampled and cultured on PDA, and the re-isolated fungal specimen was confirmed to be T. atroviride through gene sequencing. This result demonstrated that under environmental conditions conducive for pathogen development, this strain of T. atroviride is capable of causing root rot disease in sweetpotatoes. This finding is particularly significant as farmers typically store sweetpotatoes for an extended time, sometimes up to a year, which increases the possibilities for disease occurrence. Dual-culture assays are still ongoing to determine if this strain of T. atroviride could be a beneficial endophyte under different storage conditions, especially when other fungal endophytes are co-existing in the same storage root.

Peperomia mauiensis can tolerate low indoor light conditions for up to 12 months - Orville Baldos
Investigating the Effect of Hydrafiber and Biochar As a Substitute for Peat-based Substrate for Zinnia (Zinnia elegans) - Lilin Chen
The Impact of Cold and Darkness on Osmanthus fragrans Flowering and Growth - Yulong Chen
Growth and Quality of Four Zinnia Cultivars Grown in Eastern South Dakota - Kristine Lang
Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Callirhoe involucrata - James Klett
Consumer testing and surveys indicate a market for Peperomia mauiensis, an endemic succulent with potential use as an indoor potted plant - Orville Baldos
Trials of Low Elevation Tolerant Leucospermum Hybrids on Oahu, HI - Russell Galanti

Peperomia mauiensis is an endemic peperomia found on west Maui, and the islands of Molokai and Lanai. Its short stature and reddish stems and leaves make it highly ornamental. To evaluate its feasibility as an indoor foliage plant, potted plants (n=6) were grown under three light levels (0.2 mol·m-2·d-1 [low], 0.4 mol·m-2·d-1 [office] and 2.9 mol·m-2·d-1 [high] for 12 hours) in airconditioned settings (22°C, 61% RH) for 1 year. Plant height and diameter as well as visual quality [1 = poor, 2 = fair (not saleable), 3 = acceptable (saleable), 4 = good, and 5 = excellent quality) were recorded 0, 3, 6 and 12 months after placing in light chambers. Height and diameter of plants between light treatments were similar at 0 (height = 5.9 cm; diameter = 10.5 cm) and 3 (height = 7.1 cm and diameter = 15.0 cm) months after the plants were placed in light chambers. Visual quality ratings also did not differ between light treatments at 0 (3.5) and after 3 (3.6) months. After 6 months, plants under office light conditions were the tallest (10.8 cm) and the widest (18.2 cm). Visual quality ratings between treatments at 6 months were similar (3.4). At 12 months, plant height between treatments were similar (8.8 cm), but office light plants exhibited the widest diameter (23.2 cm). Visual quality ratings between treatments at 12 months were similar (2.1) but was no longer acceptable. Results of the study indicate that Peperomia mauiensis can tolerate low indoor light levels and can be used as an indoor potted foliage plant.

The increasing environmental concerns and economic pressures necessitate the search for peat moss alternative as a substrate component, aiming to balance ecological sustainability with cost-effectiveness. This study aims to assess whether the biochar (BC) and hydrafiber (HF) could be a partially replacement for peat moss for zinnia and snapdragon production. Twelve substrates were formulated by either mixing BC (20%,40%, or 60% by vol) with HF (20%, 40%, or 60% (by vol), with the remaining being peat moss or blending BC (0%, 20%,40%, and 60%, by vol) with the commercial peat moss-based substrates (CS). The physical properties of substrate, including container capacity (CC), total porosity (TP), air space (AS), bulk density (BD), and water holding capacity (WHC), and chemical properties including leachate pH and electrical conductivity (EC) were measured. Plant growth parameters including growth index (GI) and leave greenness (indicated with SPAD value), biomass, and numbers of flowers were measured biweekly. The results showed all the substrate mixes had similar AP, BD and SPAD. Treatment with 20%BC and 80%CS had the highest plant growth, biomass, and numbers of flowers for both zinnia and snapdragon plants. In conclusion, BC could be used to partially (20%) replace commercial peat moss-based substrate mix for container-grown zinnia and snapdragon production.

Osmanthus fragrans, a culturally and economically significant plant in Asian countries, exhibits unique floral characteristics influenced by endogenous metabolites. Previous studies suggest its flowering timing and intensity may be affected by environmental factors including cold and darkness. This study aimed to investigate the effects of cold and darkness factors on the response of Osmanthus fragrans flowering and growth. This experiment included 7 cold and dark treatments (plants were sitting in the dark coolers from 0-15 days) and dark-only treatments (plants were sitting in the GH with plastic bags from 0-9 days). Plant responses were assessed based on the number of flowers, height, and width measurements on the 5th, 7th, 9th, 11th, 13th, and 15th days post-treatment. The results showed there was no significant difference in plant height across treatments. Dark-only treatment for 7 days significantly increased width growth compared to the control group (9 days), and dark-cold treatment for 5, 7, 9, 11, and 13 days. The increase in the number of flowers in the cold-dark treatment for 9 and 15 days was significantly higher than in other treatments, except for the control. In conclusion, the cold and darkness could promote flowering in Osmanthus fragrans without negatively affecting plant growth.

Over the past two decades, interest in local specialty cut flower production in Eastern South Dakota has grown with several new flower farms being established across the region. However, there is currently no local, research-based information available to support growers in this new wave of interest. The purpose of this study was to assess the production and quality of four zinnia cultivars grown in Eastern South Dakota to support local specialty cut flower growers in their operations. This was a randomized complete block study with four zinnia cultivars (Zinderella Peach, Oklahoma Ivory, Queen Red Lime, and Benary’s Giant Purple) grown in 2022 and 2023. Zinnias were started in the greenhouse and then transplanted into the field in early summer each season. Harvest began each year when flowers reached maturity (July), with one harvest event taking place each week until the first frost. Harvested flowers were rated as marketable or non-marketable based on categories of stem length (18 -inch-long, 13-17.99-inch-long, 8-12.99-inch-long, and

Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Callirhoe involucrata James E. Klett and Ronda Koski Colorado State University Department of Horticulture and LA Production of attractive and desirable plants, native to the plains and prairies of central North America, can sometimes be limited due to problems associated with successful rooting of vegetative cuttings. Species that have a long period of bloom can be challenging to vegetatively propagate during the growing season, because sufficient juvenile (vegetatively) growth is necessary for high-quality cuttings. Callirhoe involucrata (winecups) is a native herbaceous perennial with sprawling stems, palmately divided leaves, and dark pink flowers that creates a long lasting, colorful groundcover in landscapes with limited or no supplemental irrigation. Winecups can be difficult to propagate due to seed dormancy and poor rooting of vegetative cuttings. Manipulating the growing conditions of stock plants to suppress reproductive growth may improve rooting success of vegetative cuttings. Based on previous research at Colorado State University with other ornamental perennials and programmed photoperiods, winecups were grown under three programmed photoperiods to determine if a particular photoperiod could be used to suppress reproductive growth and promote vegetative growth. The research was replicated three times, all conducted in a similar fashion, but at different times of the year. Results indicate that plants grown under 10-hour light and 8-hour light photoperiods remained vegetative longer when compared to plants grown under 12-hour photoperiod. Plants grown under 12-hour photoperiods had greater mean ending dry weight when compared to plants grown under 10 hour and 8-hour photoperiods. Cuttings harvested from plants grown under 8-hour photoperiod had higher percent rooting and greater number of roots per cutting when compared to vegetative cuttings harvested from plants grown under 12-hour photoperiod. Based on these research findings, plant propagators may be able to increase production of winecups by growing stock plants under 8-hour photoperiod.

Peperomia mauiensis is an endemic succulent found on the islands of Maui, Molokai and Lanai. Its reddish stems and foliage as well as its small stature make it a potential indoor ornamental plant. To assess consumer acceptance, a public plant giveaway with surveys was conducted. Fifty-six plants in plastic and ceramic pots were distributed to the public with the completion of a survey. A six-month follow up survey was conducted to assess the condition of the plant and obtain consumer feedback. During the plant giveaway, 77% of participants completed the survey. Nearly all respondents are willing to buy the plant and recommend it to friends and co-workers. Thirty percent of respondents are willing to buy the plant for $5 in a ceramic pot and $3 to $5 for a plastic pot. Six months after the giveaway, 39.5% of initial respondents completed the follow-up survey. About half of the respondents (52.9%) reported the plant was growing healthy and vigorous. The majority of the respondents did not fertilize the plant (81.3%) and did not report any pest (94.1%) and disease (88.2%) issues. Most responded that they liked it as a houseplant (88.2%) and it was easy to maintain (82.4%). Most respondents (35.3%) were willing to buy the plant again for $5. Results of the surveys indicate that there is consumer interest in Peperomia mauiensis as a new native indoor plant.

Leucospermum species are temperate climate plants native to South Africa and have restricted production regions in Hawaii limited to elevations of 457 m or higher. This limitation and competition for land has been partially responsible to a decline in Leucospermum production in Hawaii. Agriculture land at lower elevations is more abundant and cheaper, and is an option for growing low elevation tolerant varieties. Breeding programs at the University of Hawaii at Manoa have focused on developing hybrids that will perform to commercial standards for plant growth, yield and quality, and grow at or near sea level. 14 hybrids of Leucospermum were trialed at 152 m elevation on Oahu HI. 10 hybrids exhibited adequate survival and were selected for continued trial. Weahter, plant growth (height and width), flower count, flowering seasonality, and plant health data were collected from 2021-2023. Flower length and quality data, and vase life data were collected in 2024. Average relative humidity was 79%, average monthly rainfall was 3.53 cm, and average temperature was 21.8 C with maximum temperature of 33.4 C and low of 14.2 C. The 10 hybrids all had acceptable fitness at 500’ elevation. Some hybrids showed more fitness than others. Hybrid 602 had the highest overall average health (3.8) and highest total flower count. Hybrids 620 and 626 also showed excellent fitness as well as highest flower counts. While none of the hybrids are considered unfit for production in similar conditions, some did perform less well. Hybrid 88 and Hybrid 633 had the lowest average health at 3.0 followed closely by Hybrids 583 (3.2), 679 (3.3), and 563 (3.3). These varieties also had some of the lowest total flower counts. All of the hybrids in this study are considered potential candidates for release and continued trialing. Future work can include long term trialing of these plants, and trialing at different microclimates across the State.

Do Plant “Growth Regulators” Really Regulate Growth? Plant Development And Plant Growth Are Not Synonymous. - Ted DeJong
Using GDR to Enable Rosaceae Research - New Data, Functionality and Future Direction - Dorrie Main
Raspberry Cultivar Evaluation Trial in Mississippi - Apphia Santy
Evaluating Sufficiency Levels and Peach Leaf Analysis for Fertilizer Decision-Making - Juan Carlos Melgar
Common Mechanisms Controlling Fruit Shapes may be Mediated by Changes in Cell Wall Properties - Easther van der Knaap
Pomological Nomenclature: Recent Developments and Problems - David Karp

Much scientific literature refers to plant development and growth as though they are synonymous. While plant physiology texts (E.g., Taiz et al. 2015) and horticulture texts (E.g., Sansavini et al. 2019) emphasize the roles of various plant hormones in coordinating plant development, they simultaneously refer to them as plant growth regulators. On the other hand, the same texts emphasize assimilation processes and the important role of carbohydrate and nutrient availability as well as water relations in enabling growth to occur. The terms growth and development are often used interchangeably and the literature rarely emphasizes the difference between plant development and plant growth. This causes confusion and a lack of clear thinking when attempting to develop explanations for plant growth responses in specific circumstances. Hormone physiologists often try to explain particular growth responses in terms of hormonal theory whereas environmental physiologists will likely explain the same responses in terms of environmental conditions and availability for the resources required for achieving growth. In this paper I will argue for a clearer differentiation between plant development and plant growth and suggest that plant hormones should not be thought of as plant growth regulators, but rather as plant development coordinators. Plant development coordinators (plant hormones) set up the conditions necessary for plant growth but availability of plant growth substances; carbohydrate and nutrient availability along with temperature and water relations, are often what actually regulate plant growth rates. Treating development and growth as separate but interdependent processes could clarify much understanding of the underlying processes involved in the regulation of plant growth. These concepts will be discussed in the context of understanding the mechanisms involved in several physiological phenomenon of fruit trees.

Initiated in 2003, the Genome Database for Rosaceae (GDR, www.rosaceae.org) is a comprehensive community database that provides access to curated and integrated genomics, genetics, and breeding data for the biologically and economically important Rosaceae family. It serves as steward of critical research and breeding data, and provides access to online query and analysis tools that enable researchers to readily interrogate this wealth of data, facilitating basic and applied research across Rosaceae. This presentation will highlight the impact of GDR on Rosaceae research, demonstrate new data and tools, and share plans for future development and sustainability options.

Many states in the US produce raspberries, however, most of the production is concentrated in three states: California, Oregon and Washington as most raspberry cultivars grow best in regions with cool summers and mild winters. However, newer raspberry cultivars have been developed exhibiting heat tolerance. Cultivars with heat tolerance provide an opportunity for the growers in the Southern states to include raspberries in their crop production. Local Mississippi growers are interested in incorporating raspberries into their productions. However, there lacks research-based recommendations on raspberry cultivars suitable for Mississippi's climate. The objective of this study was to evaluate raspberry cultivars in terms of plant growth, heat and cold tolerance, pest and disease resistance, berry yield, quality, and fruiting season to identify the best-suited cultivars for Mississippi. This experiment was conducted in a randomized complete block design with two types of fertilizer: conventional and organic. Data collection included measurements of plant growth and performance, berry yield and quality and fruiting season. The results showed that raspberry yield, single berry weight and fruit size were influenced by fertilizer treatment. The soluble solid contents, acidity, and fruit color were not influenced by fertilizer treatment. Raspberry yield was higher for “Polka”, “Encore”, “Heritage”, and “Latham” under conventional fertilizer. Cultivars “Himbo”, “Prelude”, ‘Bp1”, and “Encore” treated with conventional fertilizer had higher single berry weight. The average fruit size of cultivars “Prelude”, “Himbo”, “Encore”, “Bp1” treated with conventional fertilizer produced larger fruits in comparison to the other cultivars. The fruit's soluble solid content was highest in “Heritage”, indicating a sweeter taste. Cultivars “Polana” and “Anne” produced fruits with the highest acidity, indicating a tarter taste compared to other cultivars. Fruit color varied between cultivars, with differences in lightness, redness, and yellow coloration.

The increasing demand for tree fruit production necessitates optimizing nutrient balance in intensified orchard systems to maximize profits efficiently. While peach growers are advised to follow Extension and recommended guidelines for fertilization, such recommendations may not align with orchard-specific variables and environmental conditions. As a consequence, crop sufficiency ranges may require updating to reflect modern growing practices and environmental factors. Although leaf nutrient analysis is the most reliable method for diagnosing tree nutritional status, the prevalence of annual fertilizer application, driven by the low cost of fertilizers relative to crop value, often leads to excessive fertilization in peach orchards. Consequently, our objective was to evaluate established sufficiency levels and leaf analysis as tools for determining the need for annual fertilizer applications. To achieve this, we implemented a two-year study involving two fertilization programs in an orchard with three rows of 17 peach trees: two rows adhered to grower standard, annual fertilization, while the remaining row followed a rational fertilization program. The latter implied applying fertilizer only when leaf analyses indicated nutrient concentrations below established sufficiency thresholds for peaches. Leaf analyses were conducted annually in July, and if nutrient concentrations were within or exceeded sufficiency thresholds, no fertilizer was applied postharvest or the following spring. If nutrient concentrations fell below sufficiency thresholds associated with a significant difference in yield and fruit quality between the two programs, fertilization occurred in late summer and during bloom time the following spring. We assessed tree quality and productivity by measuring yield (total weight of all the fruit per tree) and fruit quality (size and brix) annually. The results of the first year showed that despite deficient leaf nitrogen and phosphorus concentrations and other nutrients such as potassium, calcium, and magnesium remaining within or above their sufficiency ranges, we observed no significant differences in yield or fruit quality between trees subjected to rational and standard fertilization practices. Consequently, fertilization for the upcoming year was deemed unnecessary in trees following the rational program. The outcomes of this study are expected to guide peach growers in making informed decisions based on updated data, reducing the environmental impact of overfertilization, which is inefficient for fruit production and uneconomical, and enhancing farm profitability.

Fruit shape variation is abundantly present in horticultural crops. This variation is critical to highlight the market class as well as the culinary purpose of the produce. Many of the underlying genes have been cloned in tomato, offering insights into the molecular mechanisms of morphological diversity. Specifically, members of the OFP, TRM and SUN family regulate produce shape variation in tomato and other crops, thereby highlighting the importance of these three families in regulating phenotypic diversity. Despite the knowledge of the genes, mechanistic insights into the function of members of these three gene families are lacking. Our research on the tomato genes OVATE and OFP20 has shown that changes in produce shapes are noticeable early in the development of the flower. Cell counts in ovaries at anthesis implied that changes in cell division patterning may underlie morphological diversity. However, gene expression studies showed that morphological changes were associated with cell wall processes and not with changes in cell division patterning.

In addition to botanical names, at least a dozen distinct categories of nomenclature are applied to plant cultivars, including various forms of cultivar denominations, breeders references, and trade names. Two sets of rules, the International Code of Nomenclature for Cultivated Plants (9th ed., 2016), and the Explanatory Notes on Variety Denominations Under the UPOV Convention (2022) provide current guidelines for plant cultivar nomenclature. In some instances UPOV and ICNCP rules differ, and stakeholders may wish to consider whether it would be feasible to seek harmonization, and the mechanisms by which that might be achieved. This session will trace a brief history of cultivar denomination rules for U.S. plant patents. The United States Patent and Trademark Office, which issues plant patents, does not provide detailed nomenclatural guidelines. In the past two decades a new model for plant nomenclature has prevailed, in which an alphanumeric code serves as the official cultivar denomination, and this is paired with a trademark, either registered or unregistered. The relationship between cultivar denominations and trade names can be complex and fluid. As co-editor of the Register of New Fruit and Nut Cultivars, the presenter professionally researches all new pomological cultivar denominations and trade names, to avoid publishing names that conflict with previous names or nomenclatural standards. The establishment of an official cultivar denomination has important practical consequences that are sometimes ignored by breeders and rights owners. When a cultivar has been granted a plant patent or plant breeders’ rights, the cultivar denomination recorded by the statutory plant registration authority that issues the grant becomes officially established (a “statutory epithet”), and cannot be casually changed or replaced by the rights owner. When such informal synonyms are used, they are best regarded as trade names, often as unregistered trademarks. Common mistakes and pitfalls in nomenclature are described.

Competition participants must bring your poster pdf on a thumb drive or the physical poster to your assigned room. You will be lined up to present to the judges in order of arrival. You will enter the room one at a time.

Students will be given 5 minutes to make a presentation to the judges, followed by a 2 minute period of questions and answers.

This competition is open to graduate students that have a poster presentation scheduled during the ASHS conference AND have also signed up to participate in this competition (Note: This is separate of the assigned time to present your abstract during the conference program).

Please note that if you do not also present your poster during the regularly scheduled Poster session, you will be disqualified from the Poster Competition.