Pub Date : 2023-10-01DOI: 10.21273/hortsci17158-23
Kenneth W. Pierce, Michael P. Nattrass
Cover crops are defined as crops grown primarily for agroecosystem improvement rather than for market or sale. The use of cover crops to decrease the negative effects of weeds and improve soil and ecosystem health is increasing, but unanticipated allelopathic responses to those cover crops by subsequent crops is sometimes a problem. Allelopathy is broadly defined as the biochemical interactions between all types of plants, including microorganisms. Because allelopathic effects include both inhibitory and stimulatory responses and may be species- and cultivar-specific, a method of rapidly screening donor and recipient crops for allelopathic interactions is needed. The objective of this research was to evaluate a growth chamber bioassay for rapidly screening spinach (Spinacia oleracea L.) cultivars for allelopathic interactions with an aqueous extract from fresh whole-plant tissue of sorghum-sudangrass [Sorghum bicolor (L.) Moench; SSG] cultivars. The bioassay exposed the seed of 10 spinach cultivars to the aqueous extract of three cultivars of SSG during the imbibition and germination processes and evaluated the consequent root and stem development. Compared with the control, the extract from all three SSG cultivars decreased the root length of all spinach cultivars. A subsequent field screen where spinach cultivars were planted into decomposing SSG residue resulted in a similar pattern of growth suppression. These results demonstrate that the growth chamber bioassay is suitable for predicting allelopathic interactions between cultivars of SSG and cultivars of spinach and can be used by growers for making cultivar selection decisions when spinach follows SSG in a cropping sequence. This rapid-screening growth chamber bioassay protocol eliminates many of the environmental and other challenges frequently associated with field trials and may be adaptable for predicting allelopathic interactions among other cover crops, weeds, and subsequent market crops.
{"title":"Rapid-screening Bioassay Assessing Potential Allelopathic Influence on Spinach by Aqueous Extract from Fresh, Whole-plant Sorghum-sudangrass Tissue","authors":"Kenneth W. Pierce, Michael P. Nattrass","doi":"10.21273/hortsci17158-23","DOIUrl":"https://doi.org/10.21273/hortsci17158-23","url":null,"abstract":"Cover crops are defined as crops grown primarily for agroecosystem improvement rather than for market or sale. The use of cover crops to decrease the negative effects of weeds and improve soil and ecosystem health is increasing, but unanticipated allelopathic responses to those cover crops by subsequent crops is sometimes a problem. Allelopathy is broadly defined as the biochemical interactions between all types of plants, including microorganisms. Because allelopathic effects include both inhibitory and stimulatory responses and may be species- and cultivar-specific, a method of rapidly screening donor and recipient crops for allelopathic interactions is needed. The objective of this research was to evaluate a growth chamber bioassay for rapidly screening spinach (Spinacia oleracea L.) cultivars for allelopathic interactions with an aqueous extract from fresh whole-plant tissue of sorghum-sudangrass [Sorghum bicolor (L.) Moench; SSG] cultivars. The bioassay exposed the seed of 10 spinach cultivars to the aqueous extract of three cultivars of SSG during the imbibition and germination processes and evaluated the consequent root and stem development. Compared with the control, the extract from all three SSG cultivars decreased the root length of all spinach cultivars. A subsequent field screen where spinach cultivars were planted into decomposing SSG residue resulted in a similar pattern of growth suppression. These results demonstrate that the growth chamber bioassay is suitable for predicting allelopathic interactions between cultivars of SSG and cultivars of spinach and can be used by growers for making cultivar selection decisions when spinach follows SSG in a cropping sequence. This rapid-screening growth chamber bioassay protocol eliminates many of the environmental and other challenges frequently associated with field trials and may be adaptable for predicting allelopathic interactions among other cover crops, weeds, and subsequent market crops.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46203722","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 : 2023-10-01DOI: 10.21273/hortsci17118-23
Gabriel Campbell-Martínez, Mack Thetford, Debbie Miller, Sandra Wilson, Celina Gómez
Sandhill milkweed [ Asclepias humistrata (Walter)] is important for monarch butterfly [ Danaus plexippus (L.)] conservation efforts, yet precise cultivation practices are largely not available. We tested the effects of three fertilizer rates and four substrate types and four container types on the performance of sandhill milkweed during greenhouse production. Seedlings fertilized with a high (0.90 g per 48-cell container) controlled-release fertilizer rate of 15N–3.9P–10.0K (15–9–12 Osmocote ® Plus) had reduced performance compared with low and medium fertilizer rates (0.34 and 0.56 g per 48-cell container, respectively). Seedlings grown in large containers (∼175 mL including standard 32-cell liners and tall tree-tubes) outperformed seedlings grown in small containers (∼100 mL including standard 48-cell liners and short tree tubes). A transplant ready plant can be produced for spring within 16 weeks when seeds are sown in early January. Although sandhill milkweed seedlings can be grown under various fertilizer rates and in various containers and substrates, seedlings grown in tall tree tubes in a peat-based mix (Sunshine Mix) outperformed a nursery standard substrate and two wood fiber substrates. We recommend growing plants in a peat-based substrate within tall tree tube containers and applying a medium fertilizer rate.
沙丘乳草对帝王蝶(Danaus plexippus, L.)的保护工作很重要，但精确的栽培方法在很大程度上是不可用的。试验了三种施肥水平、四种基质类型和四种容器类型对沙山乳草温室生产性能的影响。施用15N-3.9P-10.0K (15-9-12 Osmocote®Plus)高控释肥料量(0.90 g / 48细胞容器)的幼苗，与低和中施肥量(分别为0.34 g / 48细胞容器和0.56 g / 48细胞容器)相比，表现较差。在大容器(~ 175 mL，包括标准32细胞衬垫和高树管)中生长的幼苗优于在小容器(~ 100 mL，包括标准48细胞衬垫和短树管)中生长的幼苗。在1月初播种时，16周内就可以生产出适合春季移植的植株。虽然沙丘乳草幼苗可以在不同的肥料用量和不同的容器和基质中生长，但在泥炭基混合物(阳光混合物)中生长的幼苗比苗圃标准基质和两种木纤维基质表现更好。我们建议在高大的树管容器中种植植物，并施用中等肥料。
{"title":"Effect of Fertilizer Rate, Substrate, and Container Type on Greenhouse Production of Sandhill Milkweed","authors":"Gabriel Campbell-Martínez, Mack Thetford, Debbie Miller, Sandra Wilson, Celina Gómez","doi":"10.21273/hortsci17118-23","DOIUrl":"https://doi.org/10.21273/hortsci17118-23","url":null,"abstract":"Sandhill milkweed [ Asclepias humistrata (Walter)] is important for monarch butterfly [ Danaus plexippus (L.)] conservation efforts, yet precise cultivation practices are largely not available. We tested the effects of three fertilizer rates and four substrate types and four container types on the performance of sandhill milkweed during greenhouse production. Seedlings fertilized with a high (0.90 g per 48-cell container) controlled-release fertilizer rate of 15N–3.9P–10.0K (15–9–12 Osmocote ® Plus) had reduced performance compared with low and medium fertilizer rates (0.34 and 0.56 g per 48-cell container, respectively). Seedlings grown in large containers (∼175 mL including standard 32-cell liners and tall tree-tubes) outperformed seedlings grown in small containers (∼100 mL including standard 48-cell liners and short tree tubes). A transplant ready plant can be produced for spring within 16 weeks when seeds are sown in early January. Although sandhill milkweed seedlings can be grown under various fertilizer rates and in various containers and substrates, seedlings grown in tall tree tubes in a peat-based mix (Sunshine Mix) outperformed a nursery standard substrate and two wood fiber substrates. We recommend growing plants in a peat-based substrate within tall tree tube containers and applying a medium fertilizer rate.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135275174","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 : 2023-10-01DOI: 10.21273/hortsci17229-23
Yun-long Yin, Zhi-quan Wang, Ming-yi Sun, David Creech
{"title":"Magnolia compressa Zhongshanhanxiao: A New Magnolia L. Cultivar (Magnoliaceae)","authors":"Yun-long Yin, Zhi-quan Wang, Ming-yi Sun, David Creech","doi":"10.21273/hortsci17229-23","DOIUrl":"https://doi.org/10.21273/hortsci17229-23","url":null,"abstract":"","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46985529","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 : 2023-10-01DOI: 10.21273/hortsci17246-23
Kimberly Heagy, Jonathan R. Schultheis, Travis Birdsell, Melinda Knuth, Jason K. Ward
Pumpkins ( Cucurbita sp.) grown in North Carolina are a nascent specialty crop that has only risen to a national production level in the past 10 years. There are only general cultural management guidelines for this region, resulting in variation in plant density and inefficient production. Production field studies of the cultivar Kratos were conducted to investigate the impact of plant density and row width on marketable yield and individual fruit size for large carving pumpkins. Plant densities of 2691, 3588, 5382, and 10,764 plants per hectare with row widths of 1.5 and 3.0 m were grown in 2020 and 2021 in North Carolina. Data regarding fruit size, fruit size variance, and yield per area were collected. Fruit size in terms of weight, length, and diameter increased as plant density decreased. There was no difference in fruit size variation between plant densities and row widths. The fruit number per hectare and fruit weight per hectare increased as plant density increased, with the highest production at 10,764 plants per hectare. For years combined, reducing the row width from 3.0 to 1.5 m increased the fruit weight and diameter, but not the length. Additionally, the 1.5-m row width produced more fruit weight per hectare than the 3.0-m row width for both years. Growers can optimize fruit weight per area and fruit number per area by using a density of 10,764 plants per hectare. Overall, using a row width distance that is more equidistant to the in-row spacing promotes higher fruit yield and larger fruit size.
{"title":"High-density Planting and a Smaller Row Width Increased Yield and Decreased Fruit Size of Pumpkins","authors":"Kimberly Heagy, Jonathan R. Schultheis, Travis Birdsell, Melinda Knuth, Jason K. Ward","doi":"10.21273/hortsci17246-23","DOIUrl":"https://doi.org/10.21273/hortsci17246-23","url":null,"abstract":"Pumpkins ( Cucurbita sp.) grown in North Carolina are a nascent specialty crop that has only risen to a national production level in the past 10 years. There are only general cultural management guidelines for this region, resulting in variation in plant density and inefficient production. Production field studies of the cultivar Kratos were conducted to investigate the impact of plant density and row width on marketable yield and individual fruit size for large carving pumpkins. Plant densities of 2691, 3588, 5382, and 10,764 plants per hectare with row widths of 1.5 and 3.0 m were grown in 2020 and 2021 in North Carolina. Data regarding fruit size, fruit size variance, and yield per area were collected. Fruit size in terms of weight, length, and diameter increased as plant density decreased. There was no difference in fruit size variation between plant densities and row widths. The fruit number per hectare and fruit weight per hectare increased as plant density increased, with the highest production at 10,764 plants per hectare. For years combined, reducing the row width from 3.0 to 1.5 m increased the fruit weight and diameter, but not the length. Additionally, the 1.5-m row width produced more fruit weight per hectare than the 3.0-m row width for both years. Growers can optimize fruit weight per area and fruit number per area by using a density of 10,764 plants per hectare. Overall, using a row width distance that is more equidistant to the in-row spacing promotes higher fruit yield and larger fruit size.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135274135","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 : 2023-09-01DOI: 10.21273/hortsci17277-23
Evan E. Lentz, Jessica D. Lubell-Brand, M. Brand
Aroniaberry (Aronia mitschurinii) produces small pome fruits that possess health promoting compounds. Management practices for orchards are lacking, since aroniaberry is a relatively new crop. Pruning is an important cultural practice to optimize fruit yield in orchards. The response of an established aroniaberry orchard to pruning was evaluated over three years (2020 to 2022). Pruning treatments were as follows: 1) renewal pruning (removal of shoots to the base) only in year 1; 2) renewal pruning in year 1 + thinning to 18 shoots in year 2; 3) renewal pruning in year 1 + thinning to 9 shoots in year 2; and 4) no-pruning (control). In response to renewal pruning, plants grew uniformly and vigorously, producing 28 new vegetative primary shoots with an average length of 66 cm by the end of the first growing season. Limited flowering and fruiting occurred in the second season for plants receiving pruning treatments. Fruit yield on pruned plants was significantly less than for unpruned controls. In season 2, increased thinning of renewal-pruned plants negatively affected the number of inflorescences per plant, but positively affected individual fruit fresh weight and fruit °Brix:titratable acidity ratios. Fruits from all treatments had similar monomeric anthocyanins, total phenolics and mineral content. In season 3, flower production and predicted fruit yield from pruned plants and unpruned controls were similar, even though pruned plants were substantially smaller. In the third season, there were no longer any differences between renewed + thinned plants and those that received only renewal pruning, making shoot thinning an unnecessary practice. The results of this study demonstrate that renewal pruning can be an effective way to manage and rejuvenate an aging aroniaberry orchard.
{"title":"Renewal Pruning Alone or in Combination with Thinning Pruning Affects Growth, Fruit Yield and Fruit Quality of Aroniaberry","authors":"Evan E. Lentz, Jessica D. Lubell-Brand, M. Brand","doi":"10.21273/hortsci17277-23","DOIUrl":"https://doi.org/10.21273/hortsci17277-23","url":null,"abstract":"Aroniaberry (Aronia mitschurinii) produces small pome fruits that possess health promoting compounds. Management practices for orchards are lacking, since aroniaberry is a relatively new crop. Pruning is an important cultural practice to optimize fruit yield in orchards. The response of an established aroniaberry orchard to pruning was evaluated over three years (2020 to 2022). Pruning treatments were as follows: 1) renewal pruning (removal of shoots to the base) only in year 1; 2) renewal pruning in year 1 + thinning to 18 shoots in year 2; 3) renewal pruning in year 1 + thinning to 9 shoots in year 2; and 4) no-pruning (control). In response to renewal pruning, plants grew uniformly and vigorously, producing 28 new vegetative primary shoots with an average length of 66 cm by the end of the first growing season. Limited flowering and fruiting occurred in the second season for plants receiving pruning treatments. Fruit yield on pruned plants was significantly less than for unpruned controls. In season 2, increased thinning of renewal-pruned plants negatively affected the number of inflorescences per plant, but positively affected individual fruit fresh weight and fruit °Brix:titratable acidity ratios. Fruits from all treatments had similar monomeric anthocyanins, total phenolics and mineral content. In season 3, flower production and predicted fruit yield from pruned plants and unpruned controls were similar, even though pruned plants were substantially smaller. In the third season, there were no longer any differences between renewed + thinned plants and those that received only renewal pruning, making shoot thinning an unnecessary practice. The results of this study demonstrate that renewal pruning can be an effective way to manage and rejuvenate an aging aroniaberry orchard.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42253563","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 : 2023-09-01DOI: 10.21273/hortsci17256-23
Harpreet Singh, B. Dunn, C. Fontanier, Hardeep Singh
The color of horticultural shade nets is known to influence crop growth and quality because of variations in the amount and quality of light. Four ornamental plant species (celosia, begonia, gerbera, and fountain grass) were grown under aluminet, pearl, and red shade nets plus black as the control at 50% shade intensity for 8 weeks. Black had the least transmittance (∼10% to 30% of ambient) within the red spectrum (620–750 nm), whereas red had the greatest at ∼70% to 80%. Aluminet and pearl resulted in a similar reduction in photosynthetic photon flux at ∼50% to 55% and ∼55% to 65% of ambient, respectively. Aluminet increased the shoot dry weight for begonia and celosia, whereas no differences among shade nets were seen for gerbera or fountain grass. The chlorophyll concentration was greatest under aluminet for each species except begonia. Shade net color did not affect flower number.
{"title":"Colored Shade Nets Affect Growth but Not Flowering of Four Greenhouse-grown Potted Ornamental Species","authors":"Harpreet Singh, B. Dunn, C. Fontanier, Hardeep Singh","doi":"10.21273/hortsci17256-23","DOIUrl":"https://doi.org/10.21273/hortsci17256-23","url":null,"abstract":"The color of horticultural shade nets is known to influence crop growth and quality because of variations in the amount and quality of light. Four ornamental plant species (celosia, begonia, gerbera, and fountain grass) were grown under aluminet, pearl, and red shade nets plus black as the control at 50% shade intensity for 8 weeks. Black had the least transmittance (∼10% to 30% of ambient) within the red spectrum (620–750 nm), whereas red had the greatest at ∼70% to 80%. Aluminet and pearl resulted in a similar reduction in photosynthetic photon flux at ∼50% to 55% and ∼55% to 65% of ambient, respectively. Aluminet increased the shoot dry weight for begonia and celosia, whereas no differences among shade nets were seen for gerbera or fountain grass. The chlorophyll concentration was greatest under aluminet for each species except begonia. Shade net color did not affect flower number.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44435141","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 : 2023-09-01DOI: 10.21273/hortsci17205-23
J. Fields, Kristopher S. Criscione
Bark particle screening is a critical secondary processing stage when engineering bark-based horticultural substrates. There are several factors that can influence bark screening efficiency; however, the bark moisture content immediately before screening may have the largest impact. The objectives of this study were to determine the effect bark moisture content has on bark particle separation across two commonly used screen apertures and the subsequent static physical properties of the screened bark. The moisture contents examined herein ranged from 50%, 55%, 60%, 65%, and 70% and were gravimetrically determined. The screen apertures used were 6.3 mm and 9.5 mm. The results showed that moisture content has a considerable effect on both screening yield and the physical properties. Generally, as moisture content increased, bark yield (i.e., bark processed through the aperture) decreased. Moreover, as moisture content increased, the proportions of fine bark particles adhered to coarse bark increased, shifting the air-filled porosity: water-holding capacity of the substrate. In summation, the drier moisture content had the greatest (i.e., most equal) separation, regardless of screen aperture. Future research should identify the interaction between feed rate and moisture content.
{"title":"Pine Bark Particle Separation Improves as Moisture Content Decreases at Time of Screening","authors":"J. Fields, Kristopher S. Criscione","doi":"10.21273/hortsci17205-23","DOIUrl":"https://doi.org/10.21273/hortsci17205-23","url":null,"abstract":"Bark particle screening is a critical secondary processing stage when engineering bark-based horticultural substrates. There are several factors that can influence bark screening efficiency; however, the bark moisture content immediately before screening may have the largest impact. The objectives of this study were to determine the effect bark moisture content has on bark particle separation across two commonly used screen apertures and the subsequent static physical properties of the screened bark. The moisture contents examined herein ranged from 50%, 55%, 60%, 65%, and 70% and were gravimetrically determined. The screen apertures used were 6.3 mm and 9.5 mm. The results showed that moisture content has a considerable effect on both screening yield and the physical properties. Generally, as moisture content increased, bark yield (i.e., bark processed through the aperture) decreased. Moreover, as moisture content increased, the proportions of fine bark particles adhered to coarse bark increased, shifting the air-filled porosity: water-holding capacity of the substrate. In summation, the drier moisture content had the greatest (i.e., most equal) separation, regardless of screen aperture. Future research should identify the interaction between feed rate and moisture content.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44661501","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 : 2023-09-01DOI: 10.21273/hortsci17128-23
Elizabeth Houghton, M. Noonan, K. Hannam, L. Nelson, D. Neilsen
Plant cold hardiness is a dynamic process, and seasonal changes occur through cold acclimation and deacclimation to help prevent lethal injury from the cold. Cold weather injury resulting from inadequate plant cold hardiness can result in significant economic losses to growers of perennial crops in temperate climates. The objective of the current study was to develop models that estimate the lethal temperature that causes 10%, 50%, and 90% mortality (LT10, LT50, LT90) to two cultivars of sweet cherry (Prunus avium) flower buds from the early fall through to spring. We parameterized regression models using lethal temperature data collected in the Okanagan Valley, British Columbia, Canada, over six seasons (2013–17, 2019–20, 2021–22) for ‘Sweetheart’ sweet cherry and three seasons (2013–15, 2016–17) for ‘Lapins’ sweet cherry. These models incorporate parameters that are based on equations that describe chill and heat accumulation that rely on measures of hourly air temperature. Model evaluation and validation using several seasons of lethal temperature data not included in model development were completed. Models for estimating the cold hardiness of sweet cherry showed good agreement between model lethal temperature predictions and observed values for both sweet cherry cultivars. In addition, an open-access, interactive, web-based application was developed to access the outputs of these models in real time for use by growers, researchers, and extension workers. These current models of sweet cherry cold hardiness have potential application for use as a decision support tool for cold damage management as well as crop site suitability modeling.
{"title":"Models for Estimating the Cold Hardiness of Sweet Cherry (Prunus avium cv. Sweetheart and Lapins) in Cold Climate Regions","authors":"Elizabeth Houghton, M. Noonan, K. Hannam, L. Nelson, D. Neilsen","doi":"10.21273/hortsci17128-23","DOIUrl":"https://doi.org/10.21273/hortsci17128-23","url":null,"abstract":"Plant cold hardiness is a dynamic process, and seasonal changes occur through cold acclimation and deacclimation to help prevent lethal injury from the cold. Cold weather injury resulting from inadequate plant cold hardiness can result in significant economic losses to growers of perennial crops in temperate climates. The objective of the current study was to develop models that estimate the lethal temperature that causes 10%, 50%, and 90% mortality (LT10, LT50, LT90) to two cultivars of sweet cherry (Prunus avium) flower buds from the early fall through to spring. We parameterized regression models using lethal temperature data collected in the Okanagan Valley, British Columbia, Canada, over six seasons (2013–17, 2019–20, 2021–22) for ‘Sweetheart’ sweet cherry and three seasons (2013–15, 2016–17) for ‘Lapins’ sweet cherry. These models incorporate parameters that are based on equations that describe chill and heat accumulation that rely on measures of hourly air temperature. Model evaluation and validation using several seasons of lethal temperature data not included in model development were completed. Models for estimating the cold hardiness of sweet cherry showed good agreement between model lethal temperature predictions and observed values for both sweet cherry cultivars. In addition, an open-access, interactive, web-based application was developed to access the outputs of these models in real time for use by growers, researchers, and extension workers. These current models of sweet cherry cold hardiness have potential application for use as a decision support tool for cold damage management as well as crop site suitability modeling.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45806442","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 : 2023-09-01DOI: 10.21273/hortsci17150-23
Changshan Chen, Yan-Ting Chen, Huey-Ling Lin
Two key trends of sustainable agriculture are reducing the amount of inputs such as pesticides, fungicides, or fertilizer and finding ways to reduce or reuse agricultural waste. Leafy plant waste can be burned to produced smoke-water extracts that have effective antimicrobial and germination properties. Damping-off disease caused by Pythium spp. leads to significant losses at the papaya seedling stage and is usually managed with fungicides. Five smoke-water extracts derived from burning different plant residues—namely, rice straw smoke-water (R-SW), wheat straw smoke-water (W-SW), pangola grass smoke-water (P-SW), cornstalk smoke-water (C-SW), and bamboo leave smoke-water (B-SW)—were prepared. These were mixed into the V8 media used for culture of Pythium aphanidermatum. In vitro treatment with 5% P-SW, C-SW, or B-SW reduced mycelial growth rate significantly, whereas 5% B-SW inhibited mycelial growth completely. All 1% smoke-water preparations reduced zoospore production significantly, but the inhibition rate of 3% R-SW, 3% W-SW, 1% P-SW, 1% C-SW, and 1% B-SW reached 100%. For in vivo experiments, P. aphanidermatum was inoculated in 1 kg of potting soil and mixed with B-SW in concentrations of 1% to 5%. The papaya seedlings treated with 2% to 5% B-SW maintained the growth parameter without damping-off symptoms.
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Pub Date : 2023-09-01DOI: 10.21273/hortsci17132-23
Anthony C. Percival, J. Craver
Greenhouse production of high-quality young annual bedding plants (plugs) at northern latitudes often requires supplemental lighting to compensate for a low natural daily light integral (DLI), but radiation interception by plugs is limited by a low leaf area index. Some species show an increase in leaf area in response to growth under a low ratio of red to far-red radiation (R:FR), and an early increase in leaf area may allow for more effective radiation capture by seedlings and a reduction in wasted radiation. Thus, the objective of this study was to examine the effects of end-of-day far-red (EOD-FR) radiation treatments varying in intensity, R:FR (600–700 nm/700–780 nm), and duration on early leaf expansion and plug quality for petunia (Petunia ×hybrida) ‘Wave Purple’ and ‘Dreams Midnight’. Seedlings were grown in 128-cell trays in a common greenhouse environment under a simulated winter DLI (∼5.3 mol·m−2·s−1) and received one of four EOD-FR treatments, control conditions (no EOD-FR or supplemental lighting), or supplemental lighting (target photosynthetic photon flux density of 70 μmol·m−2·s−1). The EOD-FR treatments were provided for 3 weeks on cotyledon emergence and included the following: 10 μmol·m−2·s−1 of far-red radiation for 30 minutes with a R:FR of ∼0.8 (EODFL), 10 or 20 μmol·m−2·s−1 of far-red radiation for 30 minutes with a R:FR of ∼0.15 (EOD10:30 and EOD20:30, respectively), or 20 μmol·m−2·s−1 of far-red radiation for 240 minutes with a R:FR of ∼0.15 (EOD20:240). Destructive data were collected 14 and 21 days after cotyledon emergence. Seedlings that received EOD-FR treatments did not show any increase in leaf area compared with control or supplemental lighting treatments. Stem length generally increased under EOD-FR treatments compared with supplemental lighting and control treatments; greater elongation was observed when the R:FR decreased from 0.8 to 0.15, and when treatment duration increased from 30 minutes to 240 minutes. However, at a R:FR of 0.15 and a treatment duration of 30 minutes, an increase in far-red radiation intensity from 10 to 20 μmol·m−2·s−1 did not promote further stem elongation resulting in similar stem lengths for both cultivars under EOD10:30 and EOD20:30. Results of this study indicate that under low DLIs, EOD-FR radiation applied in the first 3 weeks of seedling production does not promote early leaf area expansion, and generally decreases seedling quality for petunia. As responses to far-red radiation may vary based on study taxa, incident radiation, and DLI, future research examining EOD-FR–induced morphological changes is warranted.
{"title":"End-of-day Far-red Lighting with a Low Daily Light Integral Increases Stem Length But Does Not Promote Early Leaf Expansion for Petunia ×hybrida Seedlings","authors":"Anthony C. Percival, J. Craver","doi":"10.21273/hortsci17132-23","DOIUrl":"https://doi.org/10.21273/hortsci17132-23","url":null,"abstract":"Greenhouse production of high-quality young annual bedding plants (plugs) at northern latitudes often requires supplemental lighting to compensate for a low natural daily light integral (DLI), but radiation interception by plugs is limited by a low leaf area index. Some species show an increase in leaf area in response to growth under a low ratio of red to far-red radiation (R:FR), and an early increase in leaf area may allow for more effective radiation capture by seedlings and a reduction in wasted radiation. Thus, the objective of this study was to examine the effects of end-of-day far-red (EOD-FR) radiation treatments varying in intensity, R:FR (600–700 nm/700–780 nm), and duration on early leaf expansion and plug quality for petunia (Petunia ×hybrida) ‘Wave Purple’ and ‘Dreams Midnight’. Seedlings were grown in 128-cell trays in a common greenhouse environment under a simulated winter DLI (∼5.3 mol·m−2·s−1) and received one of four EOD-FR treatments, control conditions (no EOD-FR or supplemental lighting), or supplemental lighting (target photosynthetic photon flux density of 70 μmol·m−2·s−1). The EOD-FR treatments were provided for 3 weeks on cotyledon emergence and included the following: 10 μmol·m−2·s−1 of far-red radiation for 30 minutes with a R:FR of ∼0.8 (EODFL), 10 or 20 μmol·m−2·s−1 of far-red radiation for 30 minutes with a R:FR of ∼0.15 (EOD10:30 and EOD20:30, respectively), or 20 μmol·m−2·s−1 of far-red radiation for 240 minutes with a R:FR of ∼0.15 (EOD20:240). Destructive data were collected 14 and 21 days after cotyledon emergence. Seedlings that received EOD-FR treatments did not show any increase in leaf area compared with control or supplemental lighting treatments. Stem length generally increased under EOD-FR treatments compared with supplemental lighting and control treatments; greater elongation was observed when the R:FR decreased from 0.8 to 0.15, and when treatment duration increased from 30 minutes to 240 minutes. However, at a R:FR of 0.15 and a treatment duration of 30 minutes, an increase in far-red radiation intensity from 10 to 20 μmol·m−2·s−1 did not promote further stem elongation resulting in similar stem lengths for both cultivars under EOD10:30 and EOD20:30. Results of this study indicate that under low DLIs, EOD-FR radiation applied in the first 3 weeks of seedling production does not promote early leaf area expansion, and generally decreases seedling quality for petunia. As responses to far-red radiation may vary based on study taxa, incident radiation, and DLI, future research examining EOD-FR–induced morphological changes is warranted.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46552382","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}
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