Pub Date : 2023-12-01DOI: 10.21273/hortsci16963-22
M. McMillan, Karen Williams, Kimberly Moore, Samira Daroub, John E. Erickson, Stanley Kostka, Michael Fidanza
Methods to evaluate soil water repellency (SWR) require extensive studies on field soils and are subject to the heterogeneity of SWR throughout the soil profile as well as plant/soil interactions. The objectives of this study were to develop a synthetic method to create hydrophobic sand, and to determine if that hydrophobic sand would affect the establishment of bermudagrass (Cynodon dactylon L. Pers. × C. transvaalensis Burtt-Davy, cv. Tifeagle) sprigs. Two techniques were developed to render sand hydrophobic: soap:sand method (hydrophobic sand; HSS) and sand:peat method (hydrophobic sand and read sedge peat; HSP). Both HSS and HSP remained severely hydrophobic at 0 cm depth for only 7 d, and at the 1- to 6-cm depth for 77 continuous days, as determined by water drop penetration time. Bermudagrass establishment, root growth, or shoot growth in two greenhouse experiments with four root zone substrates–HSS, HSP, WSAND (wettable sand), and WSP (wettable sand and reed sedge peat)—were not consistent. In conclusion, both HSS and HSP were shown to be safe and effective methods to synthetically produce hydrophobic sand for potential use in laboratory research, but further evaluation is needed to determine the feasibility of using HSS and HSP for turfgrass growth evaluations.
评估土壤拒水性(SWR)的方法需要对田间土壤进行广泛的研究，并受到整个土壤剖面中土壤拒水性的异质性以及植物/土壤相互作用的影响。本研究的目的是建立一种合成疏水砂的方法，并确定疏水砂是否会影响百慕大草(Cynodon dactylon L. Pers)的生长。× C. transvaalensis Burtt-Davy, cv。Tifeagle)枝。开发了两种使砂具有疏水性的技术:皂砂法(疏水性砂;HSS)和砂:泥炭法(疏水砂和读莎草泥炭;HSP)。通过水滴渗透时间测定，HSS和HSP在0 cm深度仅持续7 d，在1 ~ 6 cm深度持续77天。在4种根区基质——hss、HSP、WSAND(可湿性砂)和WSP(可湿性砂和芦苇莎草泥炭)的2个温室试验中，百德草的建立、根生长或地上部生长均不一致。综上所述，HSS和HSP都是安全有效的合成疏水砂的方法，具有实验室研究的潜力，但需要进一步评估HSS和HSP用于草坪草生长评价的可行性。
{"title":"Evaluation of a Method to Induce Hydrophobicity on Sand","authors":"M. McMillan, Karen Williams, Kimberly Moore, Samira Daroub, John E. Erickson, Stanley Kostka, Michael Fidanza","doi":"10.21273/hortsci16963-22","DOIUrl":"https://doi.org/10.21273/hortsci16963-22","url":null,"abstract":"Methods to evaluate soil water repellency (SWR) require extensive studies on field soils and are subject to the heterogeneity of SWR throughout the soil profile as well as plant/soil interactions. The objectives of this study were to develop a synthetic method to create hydrophobic sand, and to determine if that hydrophobic sand would affect the establishment of bermudagrass (Cynodon dactylon L. Pers. × C. transvaalensis Burtt-Davy, cv. Tifeagle) sprigs. Two techniques were developed to render sand hydrophobic: soap:sand method (hydrophobic sand; HSS) and sand:peat method (hydrophobic sand and read sedge peat; HSP). Both HSS and HSP remained severely hydrophobic at 0 cm depth for only 7 d, and at the 1- to 6-cm depth for 77 continuous days, as determined by water drop penetration time. Bermudagrass establishment, root growth, or shoot growth in two greenhouse experiments with four root zone substrates–HSS, HSP, WSAND (wettable sand), and WSP (wettable sand and reed sedge peat)—were not consistent. In conclusion, both HSS and HSP were shown to be safe and effective methods to synthetically produce hydrophobic sand for potential use in laboratory research, but further evaluation is needed to determine the feasibility of using HSS and HSP for turfgrass growth evaluations.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"51 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138622466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.21273/hortsci17363-23
Steven J Knapp, Glenn S. Cole, Dominique D. A. Pincot, Cindy M. López, Omar A. Gonzalez-Benitez, Randi A. Famula
{"title":"‘UC Eclipse’, a Summer Plant-adapted Photoperiod-insensitive Strawberry Cultivar","authors":"Steven J Knapp, Glenn S. Cole, Dominique D. A. Pincot, Cindy M. López, Omar A. Gonzalez-Benitez, Randi A. Famula","doi":"10.21273/hortsci17363-23","DOIUrl":"https://doi.org/10.21273/hortsci17363-23","url":null,"abstract":"","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"2 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138626453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.21273/hortsci17370-23
Yelderem Akhoundnejad, Seyhmus Baran
Drought is a primary abiotic stressor that markedly impairs pepper growth and quality. This study aimed to investigate the effects of foliar applications of phytohormones, including salicylic acid (SA), jasmonic acid (JA), and root application of arbuscular mycorrhizal fungi (AMF), on severe and moderate drought stress of 38-day-old ‘Anemon F1’ pepper plants. The results showed that drought stress led to a considerable decrease in plant growth parameters, nutrient uptake, leaf water content, and chlorophyll content, and it increased leaf temperature, phenolic and flavonoid contents, and antioxidant enzyme activity. Nevertheless, the combined application of AMF with SA and JA demonstrated substantial synergistic effects, resulting in a notable improvement in the ability to alleviate the detrimental impacts of drought stress. Furthermore, the combined application of AMF and phytohormones exhibited a stronger effect on drought stress compared with the individual application of AMF or phytohormones alone. The application of AMF+SA and AMF+JA not only improves the availability of essential nutrients but also leads to an increase in fresh shoot weight, relative water content, leaf area, and chlorophyll and antioxidant capacity. Consequently, the combined application of SA and JA with mycorrhiza emerged as a promising treatment for enhancing pepper growth under drought-stress conditions. The positive results observed in pepper cultivation through the combined use of phytohormones and mycorrhizae in regions with limited water availability emphasize the importance of investigating the effectiveness of similar approaches in other agricultural crops.
{"title":"Boosting Drought Resistance in Pepper (Capsicum annuum L.) with the Aid of Arbuscular Mycorrhizal Fungi and Key Phytohormones","authors":"Yelderem Akhoundnejad, Seyhmus Baran","doi":"10.21273/hortsci17370-23","DOIUrl":"https://doi.org/10.21273/hortsci17370-23","url":null,"abstract":"Drought is a primary abiotic stressor that markedly impairs pepper growth and quality. This study aimed to investigate the effects of foliar applications of phytohormones, including salicylic acid (SA), jasmonic acid (JA), and root application of arbuscular mycorrhizal fungi (AMF), on severe and moderate drought stress of 38-day-old ‘Anemon F1’ pepper plants. The results showed that drought stress led to a considerable decrease in plant growth parameters, nutrient uptake, leaf water content, and chlorophyll content, and it increased leaf temperature, phenolic and flavonoid contents, and antioxidant enzyme activity. Nevertheless, the combined application of AMF with SA and JA demonstrated substantial synergistic effects, resulting in a notable improvement in the ability to alleviate the detrimental impacts of drought stress. Furthermore, the combined application of AMF and phytohormones exhibited a stronger effect on drought stress compared with the individual application of AMF or phytohormones alone. The application of AMF+SA and AMF+JA not only improves the availability of essential nutrients but also leads to an increase in fresh shoot weight, relative water content, leaf area, and chlorophyll and antioxidant capacity. Consequently, the combined application of SA and JA with mycorrhiza emerged as a promising treatment for enhancing pepper growth under drought-stress conditions. The positive results observed in pepper cultivation through the combined use of phytohormones and mycorrhizae in regions with limited water availability emphasize the importance of investigating the effectiveness of similar approaches in other agricultural crops.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"244 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135011813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.21273/hortsci17248-23
Che Deer, Bruce L. Dunn, Bizhen Hu, Carla Goad, Daniel E. Shoup
‘Cherokee Purple’ tomato ( Solanum lycopersicum L.) plants are a highly sought-after heirloom cultivar in the United States but are low yielding and highly susceptible to soil-borne pathogens, and may benefit from being grafted. Soilless systems such as aquaponics and hydroponics help increase yield, mitigate disease, and serve as an alternative to field production. The objective of this study was to evaluate a grafting combination of ‘Cherokee Purple’ × ‘Maxifort’ and nongrafted controls in 1.85-m 2 media grow beds with hydroponic and aquaponic systems using copper nose bluegill in a greenhouse. Grafting increased stem diameter, leaf count, stem height, flower count, and bud count compared with nongrafted plants. In aquaponics, grafting increased the phosphorus uptake over nongrafted plants grown in the aquaponic system. Grafting resulted in greater fresh (49.2%) and dry (40.0%) shoot biomass, and fresh (33.3%) and dry (42.8%) root biomass. Grafting also increased the uptake of copper and sulfur in the aquaponic systems. The hydroponic systems resulted in greater leaf count, soil plant analysis development, stem height, shoot biomass, and greater boron, phosphorus, potassium, iron, and manganese levels than aquaponic systems. Total fruit number and weight were greater in hydroponic systems than in aquaponic systems by 35.4% and 30.4%, respectively, but fruit splitting was a problem in both. Aquaponics resulted in greater root fresh weight than hydroponics. The nutrients zinc and copper increased with the use of aquaponic systems over hydroponic systems. This research suggests that the type of system can affect growth and nutrient uptake, and ‘Cherokee Purple’ should not be used in a soilless system because of excessive fruit splitting, leading to unmarketable fruit and low yield, unless environmental conditions can be managed during the heat of the summer.
“切罗基紫番茄”(Solanum lycopersicum L.)在美国是一种非常受欢迎的传家宝品种，但产量低，对土壤传播的病原体高度敏感，嫁接可能会受益。无土栽培系统，如鱼菜共生和水培，有助于提高产量，减轻病害，并作为田间生产的替代方案。本研究的目的是在温室中使用铜鼻蓝鳃鱼，在1.85 m 2的培养基栽培床上，用水培和水培系统嫁接‘切罗基紫’和‘马克西福特’与未嫁接的对照。与未嫁接植株相比，嫁接植株的茎粗、叶数、茎高、花数和芽数增加。在水培系统中，嫁接比未嫁接的植物增加了磷的吸收。嫁接带来了更高的鲜枝生物量(49.2%)和干枝生物量(40.0%)，以及鲜根生物量(33.3%)和干枝生物量(42.8%)。接枝也增加了水共生系统对铜和硫的吸收。水培系统比水培系统具有更高的叶片数、土壤植物分析发育、茎高、地上部生物量和更高的硼、磷、钾、铁和锰含量。水培系统的总果数和总重分别比水培系统高35.4%和30.4%，但两者都存在果裂问题。水培法的根鲜重大于水培法。与水培系统相比，水培系统增加了营养元素锌和铜的含量。这项研究表明，系统的类型可以影响生长和营养吸收，并且' Cherokee Purple '不应该用于无土系统，因为水果过度分裂，导致水果滞销和低产量，除非在夏季炎热的环境条件下可以管理。
{"title":"Grafted and Nongrafted ‘Cherokee Purple’ Tomato Performance in Aquaponic and Hydroponic Greenhouse Production in Oklahoma","authors":"Che Deer, Bruce L. Dunn, Bizhen Hu, Carla Goad, Daniel E. Shoup","doi":"10.21273/hortsci17248-23","DOIUrl":"https://doi.org/10.21273/hortsci17248-23","url":null,"abstract":"‘Cherokee Purple’ tomato ( Solanum lycopersicum L.) plants are a highly sought-after heirloom cultivar in the United States but are low yielding and highly susceptible to soil-borne pathogens, and may benefit from being grafted. Soilless systems such as aquaponics and hydroponics help increase yield, mitigate disease, and serve as an alternative to field production. The objective of this study was to evaluate a grafting combination of ‘Cherokee Purple’ × ‘Maxifort’ and nongrafted controls in 1.85-m 2 media grow beds with hydroponic and aquaponic systems using copper nose bluegill in a greenhouse. Grafting increased stem diameter, leaf count, stem height, flower count, and bud count compared with nongrafted plants. In aquaponics, grafting increased the phosphorus uptake over nongrafted plants grown in the aquaponic system. Grafting resulted in greater fresh (49.2%) and dry (40.0%) shoot biomass, and fresh (33.3%) and dry (42.8%) root biomass. Grafting also increased the uptake of copper and sulfur in the aquaponic systems. The hydroponic systems resulted in greater leaf count, soil plant analysis development, stem height, shoot biomass, and greater boron, phosphorus, potassium, iron, and manganese levels than aquaponic systems. Total fruit number and weight were greater in hydroponic systems than in aquaponic systems by 35.4% and 30.4%, respectively, but fruit splitting was a problem in both. Aquaponics resulted in greater root fresh weight than hydroponics. The nutrients zinc and copper increased with the use of aquaponic systems over hydroponic systems. This research suggests that the type of system can affect growth and nutrient uptake, and ‘Cherokee Purple’ should not be used in a soilless system because of excessive fruit splitting, leading to unmarketable fruit and low yield, unless environmental conditions can be managed during the heat of the summer.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"62 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135012572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.21273/hortsci17339-23
Noah Willsea, Victor Blanco, Orlando Howe, Thiago Campbell, Erica Casagrande Biasuz, Lee Kalcsits
Protective netting and evaporative cooling are commonly used for sunburn protection in apple ( Malus domestica Borkh.) orchards in semiarid environments such as central Washington state. Sunburn is caused by a combination of solar radiation and heat, which can cause significant economic losses. Although protective netting and evaporative cooling can be effective for preventing apple sunburn, netting can also introduce new risks, including red color development on the fruit surface. This study evaluated whether retracting netting before harvest improves red color development and/or changes sunburn risk compared with leaving netting in place until after harvest. An experiment was conducted that compared three netting treatments: 1) netting from June until harvest, 2) netting retracted 10 d before harvest, and 3) no netting all season combined with the presence or absence of evaporative cooling. Fruit was harvested and assessed for sunburn incidence and external quality characteristics immediately after harvest. In retracted netting treatments, red color was higher when netting was retracted compared with the nonretracted controls, and sunburn risk did not increase with netting retraction. Evaporative cooling reduced sunburn incidence. Retractable netting can be used to minimize the loss of fruit to sunburn while allowing a full light environment that promotes red color near harvest. There is no inherent increase in sunburn risk from netting retraction, and the proportion of fruit with red color improved.
{"title":"Retractable Netting and Evaporative Cooling for Sunburn Control and Increasing Red Color for ‘Honeycrisp’ Apple","authors":"Noah Willsea, Victor Blanco, Orlando Howe, Thiago Campbell, Erica Casagrande Biasuz, Lee Kalcsits","doi":"10.21273/hortsci17339-23","DOIUrl":"https://doi.org/10.21273/hortsci17339-23","url":null,"abstract":"Protective netting and evaporative cooling are commonly used for sunburn protection in apple ( Malus domestica Borkh.) orchards in semiarid environments such as central Washington state. Sunburn is caused by a combination of solar radiation and heat, which can cause significant economic losses. Although protective netting and evaporative cooling can be effective for preventing apple sunburn, netting can also introduce new risks, including red color development on the fruit surface. This study evaluated whether retracting netting before harvest improves red color development and/or changes sunburn risk compared with leaving netting in place until after harvest. An experiment was conducted that compared three netting treatments: 1) netting from June until harvest, 2) netting retracted 10 d before harvest, and 3) no netting all season combined with the presence or absence of evaporative cooling. Fruit was harvested and assessed for sunburn incidence and external quality characteristics immediately after harvest. In retracted netting treatments, red color was higher when netting was retracted compared with the nonretracted controls, and sunburn risk did not increase with netting retraction. Evaporative cooling reduced sunburn incidence. Retractable netting can be used to minimize the loss of fruit to sunburn while allowing a full light environment that promotes red color near harvest. There is no inherent increase in sunburn risk from netting retraction, and the proportion of fruit with red color improved.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135012573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.21273/hortsci17320-23
Clark Kogan, Lisa W. DeVetter, Gwen-Alyn Hoheisel
Freezing temperatures in fall, winter, and spring can cause damage to multiple perennial fruit crops including northern highbush blueberry ( Vaccinium corymbosum ). Predictive modeling for lethal temperatures allows producers to make informed decisions about freeze mitigation practices but is lacking for northern highbush blueberry grown in the Pacific Northwest. If buds are hardier than air temperatures, unnecessary use of propane heaters and/or wind machines is costly. In contrast, use of heaters and/or wind machines during freezing, damaging temperatures can minimize crop damage and potential yield loss. The objective of this study was to model cold hardiness across multiple cultivars of northern highbush blueberry grown in various regions in Washington, USA, and to generate predictive cold hardiness models that producers in the Pacific Northwest could use to inform freeze mitigation. Multiple years of experimental cold hardiness data were collected on four cultivars of northern highbush blueberry grown in western and eastern Washington, USA. Freeze chambers were used to reduce bud temperatures systematically, after which buds were dissected and bud survival was assessed. A generalized linear mixed model with a binomial response and logit link was fit to each cultivar to characterize the relationship between bud survival, freezer temperature, recent air temperatures, and growing degree days from fall acclimation to late winter/spring deacclimation. Model simulation was performed to obtain marginal-scale lethal temperature estimates. Model error estimation was performed using cross validation. Results show cultivar-specific cold hardiness models can be generated, and model development and use can help growers make more informed decisions regarding freeze protection that also minimizes costly applications of freeze protection when unnecessary. Furthermore, such models can be adapted to other blueberry growing regions and cultivars experiencing similar climactic conditions.
{"title":"Modeling Northern Highbush Blueberry Cold Hardiness for the Pacific Northwest","authors":"Clark Kogan, Lisa W. DeVetter, Gwen-Alyn Hoheisel","doi":"10.21273/hortsci17320-23","DOIUrl":"https://doi.org/10.21273/hortsci17320-23","url":null,"abstract":"Freezing temperatures in fall, winter, and spring can cause damage to multiple perennial fruit crops including northern highbush blueberry ( Vaccinium corymbosum ). Predictive modeling for lethal temperatures allows producers to make informed decisions about freeze mitigation practices but is lacking for northern highbush blueberry grown in the Pacific Northwest. If buds are hardier than air temperatures, unnecessary use of propane heaters and/or wind machines is costly. In contrast, use of heaters and/or wind machines during freezing, damaging temperatures can minimize crop damage and potential yield loss. The objective of this study was to model cold hardiness across multiple cultivars of northern highbush blueberry grown in various regions in Washington, USA, and to generate predictive cold hardiness models that producers in the Pacific Northwest could use to inform freeze mitigation. Multiple years of experimental cold hardiness data were collected on four cultivars of northern highbush blueberry grown in western and eastern Washington, USA. Freeze chambers were used to reduce bud temperatures systematically, after which buds were dissected and bud survival was assessed. A generalized linear mixed model with a binomial response and logit link was fit to each cultivar to characterize the relationship between bud survival, freezer temperature, recent air temperatures, and growing degree days from fall acclimation to late winter/spring deacclimation. Model simulation was performed to obtain marginal-scale lethal temperature estimates. Model error estimation was performed using cross validation. Results show cultivar-specific cold hardiness models can be generated, and model development and use can help growers make more informed decisions regarding freeze protection that also minimizes costly applications of freeze protection when unnecessary. Furthermore, such models can be adapted to other blueberry growing regions and cultivars experiencing similar climactic conditions.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"765 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135012000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.21273/hortsci17275-23
Silvia Valles-Ramirez, James E. Altland, Anna L. Testen, Jelmer W. Poelstra, Frederick C. Michel
Soilless substrates are widely used for plant cultivation. However, little is known about how soilless substrate components, plant growth, or their interactions impact microbial communities in soilless media. The objectives of this study were to analyze microbial communities in typical pine bark substrates used for nursery crop production and determine the impacts of substituting peat with a compost substrate, and planting, on microbial community dynamics over a production cycle. Three soilless substrate mixtures were compared. The substrate mixes consisted of 80:20:0, 80:10:10, and 80:0:20 (volume:volume:volume) ratios of pine bark:peatmoss:leaf compost, respectively. One set of each treatment was planted with a single birch ( Betula nigra ‘Cully’) liner and another set was not planted. The treatments (n = 3) were maintained in a nursery production setting, and samples were taken after 0, 1, 2, 3, and 4 months. Bacterial and fungal communities were characterized by sequencing polymerase chain reaction-amplified 16s rRNA genes and internal transcribed spacer regions. Initially, the two substrate mixtures that contained compost had more phyla than the substrate mixture that only contained peat and bark. After 1 month, microbial communities in all treatments contained similar phyla, but at different relative abundances based on the amount of compost they contained. Over time, Nitrosomonadaceae and Acetobacteraceae were the most abundant bacterial families in substrate mixes containing 10% and 20% compost, but they were absent from treatments without compost. The communities were dynamic and changed the most over the first 2 months. Microbial communities and their dynamics were similar between planted and unplanted treatments. Planting had less of an effect on microbial communities than compost amendment. Among the fungal communities, differences were observed based on both compost amendment and plant presence. Ascomycota and Basidiomycota were the most abundant fungal phyla and resembled those originally in the peat and compost, respectively. These findings could be used to understand the importance and dynamics of specific microbial communities present in substrate components and how they develop during greenhouse production.
{"title":"Microbial Community Structure in Soilless Substrates Used for Nursery Crops","authors":"Silvia Valles-Ramirez, James E. Altland, Anna L. Testen, Jelmer W. Poelstra, Frederick C. Michel","doi":"10.21273/hortsci17275-23","DOIUrl":"https://doi.org/10.21273/hortsci17275-23","url":null,"abstract":"Soilless substrates are widely used for plant cultivation. However, little is known about how soilless substrate components, plant growth, or their interactions impact microbial communities in soilless media. The objectives of this study were to analyze microbial communities in typical pine bark substrates used for nursery crop production and determine the impacts of substituting peat with a compost substrate, and planting, on microbial community dynamics over a production cycle. Three soilless substrate mixtures were compared. The substrate mixes consisted of 80:20:0, 80:10:10, and 80:0:20 (volume:volume:volume) ratios of pine bark:peatmoss:leaf compost, respectively. One set of each treatment was planted with a single birch ( Betula nigra ‘Cully’) liner and another set was not planted. The treatments (n = 3) were maintained in a nursery production setting, and samples were taken after 0, 1, 2, 3, and 4 months. Bacterial and fungal communities were characterized by sequencing polymerase chain reaction-amplified 16s rRNA genes and internal transcribed spacer regions. Initially, the two substrate mixtures that contained compost had more phyla than the substrate mixture that only contained peat and bark. After 1 month, microbial communities in all treatments contained similar phyla, but at different relative abundances based on the amount of compost they contained. Over time, Nitrosomonadaceae and Acetobacteraceae were the most abundant bacterial families in substrate mixes containing 10% and 20% compost, but they were absent from treatments without compost. The communities were dynamic and changed the most over the first 2 months. Microbial communities and their dynamics were similar between planted and unplanted treatments. Planting had less of an effect on microbial communities than compost amendment. Among the fungal communities, differences were observed based on both compost amendment and plant presence. Ascomycota and Basidiomycota were the most abundant fungal phyla and resembled those originally in the peat and compost, respectively. These findings could be used to understand the importance and dynamics of specific microbial communities present in substrate components and how they develop during greenhouse production.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"62 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135012571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.21273/hortsci17287-23
Anish Malladi, Krittika V. Tonapi, Thomas M. Kon
Aminoethoxyvinylglycine (AVG) is widely used in commercial apple ( Malus × domestica Borkh.) production to reduce preharvest fruit drop (PFD) and delay ripening for harvest management. Recently, the maximum allowable concentration of AVG was doubled (up to 264 mg⋅L −1 ). Reports of the relationship between the AVG concentration and fruit growth, size, and quality have been contradictory. We evaluated the relationship between the AVG concentration and PFD, fruit size, fruit quality, and expression of ethylene signaling-related and cell wall modification-related genes. Experiments were conducted in 2019 and 2020 using mature ‘Red Delicious’ in western North Carolina. The AVG treatments [0 and 132 (AVG-1x) and 264 mg⋅L −1 (AVG-2x)] were applied 3 weeks before the expected harvest. The AVG treatments reduced fruit drop and internal ethylene concentration relative to the control in both years. There was no difference in drop between AVG-1x and AVG-2x applications. Only in 2020 did AVG treatments delay fruit softening and starch hydrolysis and reduce soluble solids concentration. There were no effects on red fruit color development. Fruit size was unaffected by AVG in 2019, but it was reduced in 2020 with the AVG-2x application. AVG reduced ethylene synthesis and altered signaling, evidenced by decreased relative expression of genes related to ethylene signaling ( ARGOS1, ARGOS2 ). AVG applications also reduced the expression of EXPA8;1 , suggesting that reduced cell wall disassembly was associated with a reduction in fruit softening. These results indicate that preharvest applications of 132 mg⋅L −1 AVG effectively reduced PFD via altering ethylene evolution and signaling. Use of a higher AVG concentration was of limited benefit.
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