Pub Date : 2023-12-01DOI: 10.21273/hortsci17430-23
Madhav Parajuli, Jacob H. Shreckhise, Donna Fare, Benjamin Moore, P. Liyanapathiranage, Pratima Subedi, F. Baysal-Gurel
Susceptibility to low-temperature injury and diseases is a major concern associated with ornamental camellia production. To comprehensively understand their growth, cold-hardiness, flowering, and disease resistance, 24 camellia (Camellia spp. and hybrids) cultivars and selections were evaluated in McMinnville, TN, USA (USDA plant hardiness zone 7a). During Mar 2011, camellias were planted in the field plots. Plant height and canopy width were measured annually from 2011 to 2019, and low-temperature damage was recorded in 2014 and 2023. The flowering duration was recorded each year from 2011 to 2020. The Camellia Yellow Mottle Virus, monochaetia leaf spot (Monochaetia sp.), edema, flower blight (Ciborinia camelliae), and flower spot (Botrytis cinerea) severity (% affected) were evaluated from Oct to Nov in 2016 and 2017. The season-long area under the disease progress curve (AUDPC) was calculated. Cultivars Arctic Snow and Pink Icicle exhibited the greatest height, and Autumn Spirit, Elaine Lee, Arctic Snow, and Survivor had the widest canopy width, whereas Shishigashira had the lowest height and canopy width. ‘April Remembered’, ‘April Rose’, ‘Arctic Snow’, ‘Ashton’s Ballet’, ‘Autumn Carnival’, ‘Autumn Spirit’, ‘Elaine Lee’, ‘Survivor’, and C. chekiangoleosa selection were least affected by winter low temperatures, whereas ‘Korean Snow’, ‘One Alone’, C. sasanqua selection, ‘Pink Icicle’, and ‘Shishigashira’ were severely damaged. ‘Arctic Snow’ flowered most reliably (6 of 8 years), whereas ‘April Remembered’, ‘April Rose’, ‘Ashton’s Ballet’, ‘Autumn Spirit’, and ‘Survivor’ flowered five times. ‘Korean Fire’, ‘Classic Pink’, ‘Maroon Mist’, and ‘Spring’s Promise’ displayed the highest virus severity and AUDPC. ‘Arctic Snow’, C. sasanqua selection, and the C. chekiangoleosa selection had no viral symptoms. C. sasanqua selection and ‘Red Aurora’ were significantly impacted by edema disorder, with severity ratings of ∼43% and 26%, respectively. Monochaetia leaf spot severity was highest in ‘Red Aurora’ and ‘Spring’s Promise’, whereas ‘Anacostia’, ‘Arctic Snow’, ‘Ashton’s Ballet’, ‘Autumn Spirit’, ‘Classic Pink’, ‘Kuro Delight’, ‘One Alone’, ‘Pink Icicle’, ‘Shishigashira’, and ‘Survivor’ exhibited the least monochaetia leaf spot severity and AUDPC. Flower blight and flower spot were observed only in ‘Arctic Snow’ and ‘Survivor’. These findings will aid landscapers and nursery growers with selecting and managing camellia cultivars effectively.
{"title":"Evaluation of Camellia Cultivars and Selections for Growth, Cold-hardiness, Flowering, and Disease Resistance in Tennessee, USA","authors":"Madhav Parajuli, Jacob H. Shreckhise, Donna Fare, Benjamin Moore, P. Liyanapathiranage, Pratima Subedi, F. Baysal-Gurel","doi":"10.21273/hortsci17430-23","DOIUrl":"https://doi.org/10.21273/hortsci17430-23","url":null,"abstract":"Susceptibility to low-temperature injury and diseases is a major concern associated with ornamental camellia production. To comprehensively understand their growth, cold-hardiness, flowering, and disease resistance, 24 camellia (Camellia spp. and hybrids) cultivars and selections were evaluated in McMinnville, TN, USA (USDA plant hardiness zone 7a). During Mar 2011, camellias were planted in the field plots. Plant height and canopy width were measured annually from 2011 to 2019, and low-temperature damage was recorded in 2014 and 2023. The flowering duration was recorded each year from 2011 to 2020. The Camellia Yellow Mottle Virus, monochaetia leaf spot (Monochaetia sp.), edema, flower blight (Ciborinia camelliae), and flower spot (Botrytis cinerea) severity (% affected) were evaluated from Oct to Nov in 2016 and 2017. The season-long area under the disease progress curve (AUDPC) was calculated. Cultivars Arctic Snow and Pink Icicle exhibited the greatest height, and Autumn Spirit, Elaine Lee, Arctic Snow, and Survivor had the widest canopy width, whereas Shishigashira had the lowest height and canopy width. ‘April Remembered’, ‘April Rose’, ‘Arctic Snow’, ‘Ashton’s Ballet’, ‘Autumn Carnival’, ‘Autumn Spirit’, ‘Elaine Lee’, ‘Survivor’, and C. chekiangoleosa selection were least affected by winter low temperatures, whereas ‘Korean Snow’, ‘One Alone’, C. sasanqua selection, ‘Pink Icicle’, and ‘Shishigashira’ were severely damaged. ‘Arctic Snow’ flowered most reliably (6 of 8 years), whereas ‘April Remembered’, ‘April Rose’, ‘Ashton’s Ballet’, ‘Autumn Spirit’, and ‘Survivor’ flowered five times. ‘Korean Fire’, ‘Classic Pink’, ‘Maroon Mist’, and ‘Spring’s Promise’ displayed the highest virus severity and AUDPC. ‘Arctic Snow’, C. sasanqua selection, and the C. chekiangoleosa selection had no viral symptoms. C. sasanqua selection and ‘Red Aurora’ were significantly impacted by edema disorder, with severity ratings of ∼43% and 26%, respectively. Monochaetia leaf spot severity was highest in ‘Red Aurora’ and ‘Spring’s Promise’, whereas ‘Anacostia’, ‘Arctic Snow’, ‘Ashton’s Ballet’, ‘Autumn Spirit’, ‘Classic Pink’, ‘Kuro Delight’, ‘One Alone’, ‘Pink Icicle’, ‘Shishigashira’, and ‘Survivor’ exhibited the least monochaetia leaf spot severity and AUDPC. Flower blight and flower spot were observed only in ‘Arctic Snow’ and ‘Survivor’. These findings will aid landscapers and nursery growers with selecting and managing camellia cultivars effectively.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"16 16","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138624454","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/hortsci17466-23
Kim D. Bowman
{"title":"Four New SuperSour Rootstocks for Improved Production of Sweet Orange in a Huanglongbing Environment","authors":"Kim D. Bowman","doi":"10.21273/hortsci17466-23","DOIUrl":"https://doi.org/10.21273/hortsci17466-23","url":null,"abstract":"","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" 548","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138611038","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/hortsci17270-23
Margaret L. Worthington, John R. Clark
{"title":"‘Whitewater’ Peach","authors":"Margaret L. Worthington, John R. Clark","doi":"10.21273/hortsci17270-23","DOIUrl":"https://doi.org/10.21273/hortsci17270-23","url":null,"abstract":"","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" 10","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138616406","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/hortsci17342-23
Susmita Gaire, Ute Albrecht, Fernando Alferez
Huanglongbing (HLB), an important citrus disease, causes many physiological and anatomical changes such as phloem dysfunction, imbalance in carbohydrate partitioning, decrease in leaf chlorophyll, and nutritional imbalances in the affected trees, ultimately resulting in tree decline. In Florida, HLB is associated with phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas), and it is vectored by the Asian citrus psyllid (Diaphorina citri). No cure for HLB has been found, and most of the HLB management efforts have been focused on vector control or exclusion, improved nutrient management, and the use of HLB-tolerant rootstocks. Individual protective covers (IPCs) are a type of psyllid exclusion tool that is increasingly used by growers for HLB management of newly planted citrus trees. However, no studies have evaluated their influence on citrus tree physiology. This study investigated the effect of IPCs and different rates of insecticides on CLas infection and different physiological attributes, including soluble (glucose, fructose, and sucrose) and nonsoluble (starch) carbohydrates, leaf chlorophyll, and leaf macronutrients and micronutrients over 2.5 years of field growth. The treatments (tree cover and insecticides rate) were applied in newly planted ‘Valencia’ sweet orange (Citrus sinensis) trees grafted on ‘Cleopatra’ (C. reticulata) rootstock. The IPCs prevented CLas transmission and accumulation of foliar starch, sucrose, and glucose commonly associated with HLB. IPC-covered trees had more leaf chlorophyll-a and chlorophyll-b than noncovered trees and more leaf nitrogen (N) and zinc (Zn). Our findings suggest that IPCs effectively prevent CLas infection and maintain the physiological health of young citrus trees under heavy HLB pressure. Therefore, IPCs are recommended as an important component of integrated pest management for this devastating disease.
{"title":"Effect of Individual Protective Covers on Young ‘Valencia’ Orange (Citrus sinensis) Tree Physiology","authors":"Susmita Gaire, Ute Albrecht, Fernando Alferez","doi":"10.21273/hortsci17342-23","DOIUrl":"https://doi.org/10.21273/hortsci17342-23","url":null,"abstract":"Huanglongbing (HLB), an important citrus disease, causes many physiological and anatomical changes such as phloem dysfunction, imbalance in carbohydrate partitioning, decrease in leaf chlorophyll, and nutritional imbalances in the affected trees, ultimately resulting in tree decline. In Florida, HLB is associated with phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas), and it is vectored by the Asian citrus psyllid (Diaphorina citri). No cure for HLB has been found, and most of the HLB management efforts have been focused on vector control or exclusion, improved nutrient management, and the use of HLB-tolerant rootstocks. Individual protective covers (IPCs) are a type of psyllid exclusion tool that is increasingly used by growers for HLB management of newly planted citrus trees. However, no studies have evaluated their influence on citrus tree physiology. This study investigated the effect of IPCs and different rates of insecticides on CLas infection and different physiological attributes, including soluble (glucose, fructose, and sucrose) and nonsoluble (starch) carbohydrates, leaf chlorophyll, and leaf macronutrients and micronutrients over 2.5 years of field growth. The treatments (tree cover and insecticides rate) were applied in newly planted ‘Valencia’ sweet orange (Citrus sinensis) trees grafted on ‘Cleopatra’ (C. reticulata) rootstock. The IPCs prevented CLas transmission and accumulation of foliar starch, sucrose, and glucose commonly associated with HLB. IPC-covered trees had more leaf chlorophyll-a and chlorophyll-b than noncovered trees and more leaf nitrogen (N) and zinc (Zn). Our findings suggest that IPCs effectively prevent CLas infection and maintain the physiological health of young citrus trees under heavy HLB pressure. Therefore, IPCs are recommended as an important component of integrated pest management for this devastating disease.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" 10","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138616873","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}
The art of pressed flowers is a method of artistic expression involving the pressing of flowers, leaves, and other plant organs for artistic creative purposes. However, the pressing process often results in color variation of the plant material, which significantly diminishes the quality of artistic works and must be solved using appropriate techniques. During this research, phenylalanine (10 mmol⋅L−1) was used to treat the petals of postharvest Petunia flowers to investigate the impact of phenylalanine on mitigating color variation, and the effect of phenylalanine on inhibiting the color variation of Petunia petals during the pressing process was evaluated by color measurement, physicochemical indices, and gene expression level analyses. Using the CIEL*a*b* color measurements, the samples from the test group had significantly higher brightness (L*) and red coloration (a*) at the final stage (S4) than the control group. In addition, phenylalanine had a significant inhibitory effect on malondialdehyde and superoxide anion accumulations in Petunia petals during pressing and reduced the enzymatic activities of superoxide dismutase, polyphenol oxidase, and catalase. The quantitative reverse-transcription polymerase chain reaction analysis showed that the transcript levels of CHS, DFR, F3′5′H, and UFGT genes in the petals of the treatment group continued to increase during the pressing process, and the transcript levels of key genes in the anthocyanin metabolic pathway of the treated samples were higher than those of the control group at the final stage (S4). These results indicated that phenylalanine can effectively diminish the color variation of Petunia petals in the pressing process, which could serve as a theoretical basis for the development of a comprehensive technology system aimed at preserving the color of pressed horticultural plants.
{"title":"Phenylalanine Mitigates the Phenotypic Color Variations in Pressed Petals of Petunia hybrida ‘Red Sun’","authors":"Jing Li, Zhengtao Huang, Jing Yang, Chengcheng Xie, Qiang Wu, Xuzixin Zhou","doi":"10.21273/hortsci17383-23","DOIUrl":"https://doi.org/10.21273/hortsci17383-23","url":null,"abstract":"The art of pressed flowers is a method of artistic expression involving the pressing of flowers, leaves, and other plant organs for artistic creative purposes. However, the pressing process often results in color variation of the plant material, which significantly diminishes the quality of artistic works and must be solved using appropriate techniques. During this research, phenylalanine (10 mmol⋅L−1) was used to treat the petals of postharvest Petunia flowers to investigate the impact of phenylalanine on mitigating color variation, and the effect of phenylalanine on inhibiting the color variation of Petunia petals during the pressing process was evaluated by color measurement, physicochemical indices, and gene expression level analyses. Using the CIEL*a*b* color measurements, the samples from the test group had significantly higher brightness (L*) and red coloration (a*) at the final stage (S4) than the control group. In addition, phenylalanine had a significant inhibitory effect on malondialdehyde and superoxide anion accumulations in Petunia petals during pressing and reduced the enzymatic activities of superoxide dismutase, polyphenol oxidase, and catalase. The quantitative reverse-transcription polymerase chain reaction analysis showed that the transcript levels of CHS, DFR, F3′5′H, and UFGT genes in the petals of the treatment group continued to increase during the pressing process, and the transcript levels of key genes in the anthocyanin metabolic pathway of the treated samples were higher than those of the control group at the final stage (S4). These results indicated that phenylalanine can effectively diminish the color variation of Petunia petals in the pressing process, which could serve as a theoretical basis for the development of a comprehensive technology system aimed at preserving the color of pressed horticultural plants.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" 41","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138618300","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/hortsci17273-23
Melinda Knuth, Vanessa Woods, Xuan (Jade) Wu, Charlie Hall, Marco Palma
Florists use design theory to create arrangements that they assume will be pleasing to consumers, thus increasing purchase rates and spending. However, certain elements of design theory and their relationship with consumer acceptance and spending have not been empirically tested. Using mixed logit models and eye-tracking technology, we investigated whether consumer preferences support three key elements of existing floral design theory: line, color, and form. We also examined consumer preferences for floral species, which, although not a traditional element of design theory, may influence consumer purchasing decisions. Our findings challenge existing design theory because consumers did not uniformly favor it. Instead, they valued symmetrical form, arrangements with similar (but not identical) colors, and, surprisingly, the presence of roses in an arrangement was the most crucial factor in capturing consumer attention and increasing the willingness to pay.
{"title":"Elements of Style in Floral Arrangements: How Discerning Are Consumers Toward Floristry Design Principles and How Much Are They Willing to Pay?","authors":"Melinda Knuth, Vanessa Woods, Xuan (Jade) Wu, Charlie Hall, Marco Palma","doi":"10.21273/hortsci17273-23","DOIUrl":"https://doi.org/10.21273/hortsci17273-23","url":null,"abstract":"Florists use design theory to create arrangements that they assume will be pleasing to consumers, thus increasing purchase rates and spending. However, certain elements of design theory and their relationship with consumer acceptance and spending have not been empirically tested. Using mixed logit models and eye-tracking technology, we investigated whether consumer preferences support three key elements of existing floral design theory: line, color, and form. We also examined consumer preferences for floral species, which, although not a traditional element of design theory, may influence consumer purchasing decisions. Our findings challenge existing design theory because consumers did not uniformly favor it. Instead, they valued symmetrical form, arrangements with similar (but not identical) colors, and, surprisingly, the presence of roses in an arrangement was the most crucial factor in capturing consumer attention and increasing the willingness to pay.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"357 12","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138625771","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}
{"title":"‘Lilac Marble’: A New Hybrid Cultivar of Magnolia","authors":"Wenqian Zhang, Zachary J. Hutzell, Donglin Zhang, Xiaoling Jin, Qiulin Liao","doi":"10.21273/hortsci17414-23","DOIUrl":"https://doi.org/10.21273/hortsci17414-23","url":null,"abstract":"","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138618046","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/hortsci17317-23
R. K. Gallardo, Xueying Ma, Ann Colonna, Maria Laura Montero, Carolyn F. Ross
A significant challenge faced by the US Pacific Northwest pear industry is the limited availability of diverse pear cultivars beyond conventional selections. This scant availability of new pear options that align with consumers’ consistent quality preferences falls short of their expectations and jeopardizes potential demand growth, which poses a threat to the industry’s long-term economic viability. We use a combined approach of sensory evaluation and contingent valuation to uncover preferences and willingness to pay (WTP) for specific pear cultivars, encompassing both novel and traditional types. The outcomes reveal that the key determinants driving WTP are taste and texture attributes. Particularly for early-season pears, a greater liking score for flavor, firmness, and juiciness corresponds to an elevated WTP. For late-season pears, the range of quality attributes expands to encompass overall appearance and sweetness, in addition to the aforementioned factors. Participants who use social media to access information about pears exhibit a heightened WTP. These findings provide valuable insights for the industry to consider revitalizing existing pear orchards through the incorporation of alternatives to conventional pear cultivars.
{"title":"Consumers’ Preferences for Novel and Traditional Pear Cultivars: Evidence from Sensory Evaluation and Willingness-to-pay Elicitation","authors":"R. K. Gallardo, Xueying Ma, Ann Colonna, Maria Laura Montero, Carolyn F. Ross","doi":"10.21273/hortsci17317-23","DOIUrl":"https://doi.org/10.21273/hortsci17317-23","url":null,"abstract":"A significant challenge faced by the US Pacific Northwest pear industry is the limited availability of diverse pear cultivars beyond conventional selections. This scant availability of new pear options that align with consumers’ consistent quality preferences falls short of their expectations and jeopardizes potential demand growth, which poses a threat to the industry’s long-term economic viability. We use a combined approach of sensory evaluation and contingent valuation to uncover preferences and willingness to pay (WTP) for specific pear cultivars, encompassing both novel and traditional types. The outcomes reveal that the key determinants driving WTP are taste and texture attributes. Particularly for early-season pears, a greater liking score for flavor, firmness, and juiciness corresponds to an elevated WTP. For late-season pears, the range of quality attributes expands to encompass overall appearance and sweetness, in addition to the aforementioned factors. Participants who use social media to access information about pears exhibit a heightened WTP. These findings provide valuable insights for the industry to consider revitalizing existing pear orchards through the incorporation of alternatives to conventional pear cultivars.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"203 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138621600","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/hortsci17399-23
Ivan Simko, K. Subbarao, R. Hayes
Lettuce drop caused by Sclerotinia minor is a damaging disease of romaine lettuce (Lactuca sativa L.) production in California. Introgression of partial resistance from wild, primitive, or heirloom accessions into modern cultivars could improve integrated management approaches to the disease. Breeding methods for lettuce drop resistance are not well developed and hinder the development of new lettuce drop–resistant cultivars. The objective of this work was to develop a pedigree-based breeding method for introgression of lettuce drop resistance into modern romaine germplasm. Progeny from crosses between the partially resistant cultivar Eruption and the susceptible romaine cultivars Darkland and Hearts Delight were selected in a modified pedigree breeding scheme. Families were evaluated for disease incidence and selected for lettuce drop resistance in artificially infested field experiments conducted in the summer and fall. Infected plants of partially resistant lines commonly do not produce seed, and therefore selection of resistant plants from infested nurseries is not possible. Noninfested field experiments were used to select individual plants with improved horticultural characteristics for seed production, but from within resistant families only. Evaluation and selection of progeny using this breeding scheme occurred from the F2:3 through the F5:6 generations. In all generations, superior resistance was identified in the ‘Eruption’ × romaine crosses. The breeding scheme generated eight green romaine-type inbred lines with better resistance than the romaine parent and better head weight than ‘Eruption’. Use of the new romaine lines as parents in backcrosses to romaine produced F2:3 families with high levels of resistance. The pedigree method used in this research can be implemented with any source of resistance, but is constrained by the use of family selection and the inability to select individual plants for resistance directly. Breeding schemes that use single seed descent or molecular markers are alternative approaches that would enable selection for resistance on individual genotypes.
{"title":"Breeding Lettuce for Resistance against Sclerotinia minor","authors":"Ivan Simko, K. Subbarao, R. Hayes","doi":"10.21273/hortsci17399-23","DOIUrl":"https://doi.org/10.21273/hortsci17399-23","url":null,"abstract":"Lettuce drop caused by Sclerotinia minor is a damaging disease of romaine lettuce (Lactuca sativa L.) production in California. Introgression of partial resistance from wild, primitive, or heirloom accessions into modern cultivars could improve integrated management approaches to the disease. Breeding methods for lettuce drop resistance are not well developed and hinder the development of new lettuce drop–resistant cultivars. The objective of this work was to develop a pedigree-based breeding method for introgression of lettuce drop resistance into modern romaine germplasm. Progeny from crosses between the partially resistant cultivar Eruption and the susceptible romaine cultivars Darkland and Hearts Delight were selected in a modified pedigree breeding scheme. Families were evaluated for disease incidence and selected for lettuce drop resistance in artificially infested field experiments conducted in the summer and fall. Infected plants of partially resistant lines commonly do not produce seed, and therefore selection of resistant plants from infested nurseries is not possible. Noninfested field experiments were used to select individual plants with improved horticultural characteristics for seed production, but from within resistant families only. Evaluation and selection of progeny using this breeding scheme occurred from the F2:3 through the F5:6 generations. In all generations, superior resistance was identified in the ‘Eruption’ × romaine crosses. The breeding scheme generated eight green romaine-type inbred lines with better resistance than the romaine parent and better head weight than ‘Eruption’. Use of the new romaine lines as parents in backcrosses to romaine produced F2:3 families with high levels of resistance. The pedigree method used in this research can be implemented with any source of resistance, but is constrained by the use of family selection and the inability to select individual plants for resistance directly. Breeding schemes that use single seed descent or molecular markers are alternative approaches that would enable selection for resistance on individual genotypes.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" December","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138610993","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/hortsci17359-23
Nirmal Timilsina, O. Batuman, Fernando Alferez, D. Kadyampakeni, Ruby Tiwari, Ramdas G. Kanissery
The prevalence of Huanglongbing (HLB) disease, also known as citrus greening, has compelled the citrus industry to change management practices to increase production. However, these changes, such as enhanced nutrition and irrigation programs, have caused weed proliferation, subsequently leading to increased use of herbicides. Thus, our study evaluated a popular preemergence herbicide active ingredient, diuron, for nontarget impacts on young Hamlin and Valencia sweet orange (Citrus sinensis L. Osbek) trees in two commercial orchards in southwest Florida. The treatments included the preemergence application of diuron at three rates (1.8, 3.6, and 7.3 kg a.i./ha), a weed-checked control (using postemergence herbicides: glufosinate ammonium + saflufenacil), and a nontreated control. The treatments were applied twice (in Fall 2021 and Spring 2022) in a randomized complete block with four replicates. Results indicate that over a 5-month period, the application of diuron generally had no significant impact on citrus root growth. Further, over a 2-month observation period for Hamlin and a 4-month observation period for Valencia, it was found that diuron application had no notable effect on fruit detachment force. Valencia trees treated with diuron high showed higher HLB disease severity at location 1. In addition, Hamlin trees treated with diuron low and medium showed higher fruit drop (∼19% more) than the untreated control at location 1. However, this trend was inconsistent across the locations and cultivars. This result suggests that increased disease severity and fruit drop were not associated with diuron treatment. Thus, our study finds diuron as a tree-safe option for preemergence weed suppression in citrus production, as long as it is used in accordance with the recommended dosage and restrictions stated on the herbicide label.
黄龙病(HLB)的流行，也被称为柑橘绿化，迫使柑橘产业改变管理做法，以增加产量。然而，这些变化，如营养改善和灌溉计划，导致杂草繁殖，随后导致除草剂的使用增加。因此，我们的研究评估了一种流行的发芽前除草剂活性成分，迪乌隆，对佛罗里达州西南部两个商业果园的Hamlin和Valencia甜橙(Citrus sinensis L. Osbek)幼树的非目标影响。处理包括出苗前以三种剂量(1.8、3.6和7.3 kg a.i./ha)施用迪乌隆，杂草控制(使用出苗后除草剂:草铵膦+氟虫腈)和未处理的控制。在四个重复的随机完整区中，两次(2021年秋季和2022年春季)施用这些处理。结果表明，施用迪乌隆5个月后，对柑桔根系生长无显著影响。此外，对Hamlin和Valencia分别进行了2个月和4个月的观察，发现施用迪乌隆对果实剥离力无显著影响。在1号位置，用高浓度迪乌隆处理的瓦伦西亚树HLB病的严重程度更高。此外，在1号位置，低浓度和中浓度处理的Hamlin树的落果量比未处理的高出19%。然而，这一趋势在不同的地点和品种之间并不一致。这一结果表明，疾病严重程度的增加和果实掉落与迪乌隆治疗无关。因此，我们的研究发现，只要按照除草剂标签上的推荐剂量和限制使用，迪乌龙是柑橘生产中出现前杂草抑制的树木安全选择。
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