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。
{"title":"Nontarget Effects of Preemergence Herbicide Diuron in Hamlin and Valencia Sweet Orange (Citrus sinensis L. Osbek) in Florida","authors":"Nirmal Timilsina, O. Batuman, Fernando Alferez, D. Kadyampakeni, Ruby Tiwari, Ramdas G. Kanissery","doi":"10.21273/hortsci17359-23","DOIUrl":"https://doi.org/10.21273/hortsci17359-23","url":null,"abstract":"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.","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":"138618360","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/hortsci17372-23
D. Kadyampakeni, Tanyaradzwa Chinyukwi, Samuel Kwakye, Lorenzo Rossi
Candidatus Liberibacter asiaticus (CLas), which causes huanglongbing (HLB) in citrus trees, has a great impact on tree root health, fruit development, and juice quality. HLB-affected trees have a fibrous root density loss of ∼30% to 80%, resulting in the limited capacity of citrus trees to uptake nutrients. Therefore, this study was conducted for 3 years to 1) assess the temporal changes in root density as a result of varied fertilization, 2) determine dynamics of HLB with regard to root growth and distribution as a result of varied fertilization for Valencia orange trees, and 3) evaluate the impact of varied fertilization rate and method of fertilization on fruit yield for HLB-affected trees. Macronutrients and micronutrients were applied at varying fertilization rates (0×, 1×, 2×, and 4×, of University of Florida guidelines). Root scans were done using minirhizotrons at 0 to 19.1 cm, 19.1 to 40.7 cm, 38.2 to 59.8 cm, and 57.3 to 78.9 cm soil depths. Results obtained from the study showed that root growth and distribution were greater in 0 to 19.1 cm than 19.1 to 40.7 cm to 57.3 to 78.9 cm soil depths. Thus, root growth decreased (P < 0.0004) with increasing soil depth due to variation in nutrient availability for tree uptake. Increased nutrient availability at occurrence of physiological processes in citrus trees also influenced root growth and distribution, resulting in root growth flushes in the months of Nov to early Feb and Jul to early Aug. Fruit yield was significantly different between treatments in 2 of the 4 years of the study (P = 0.001 and P = 0.003), and largely ascribed to soil fertilization of micronutrients compared with foliar. Therefore, at higher fertilization rates, particularly via soil application, nutrient availability was increased, thus promoting root growth and distribution and fruit yield in HLB-affected orange trees.
{"title":"Varied Macro- and Micronutrient Fertilization Rates Impact Root Growth and Distribution and Fruit Yield of Huanglongbing-affected Valencia Orange Trees","authors":"D. Kadyampakeni, Tanyaradzwa Chinyukwi, Samuel Kwakye, Lorenzo Rossi","doi":"10.21273/hortsci17372-23","DOIUrl":"https://doi.org/10.21273/hortsci17372-23","url":null,"abstract":"Candidatus Liberibacter asiaticus (CLas), which causes huanglongbing (HLB) in citrus trees, has a great impact on tree root health, fruit development, and juice quality. HLB-affected trees have a fibrous root density loss of ∼30% to 80%, resulting in the limited capacity of citrus trees to uptake nutrients. Therefore, this study was conducted for 3 years to 1) assess the temporal changes in root density as a result of varied fertilization, 2) determine dynamics of HLB with regard to root growth and distribution as a result of varied fertilization for Valencia orange trees, and 3) evaluate the impact of varied fertilization rate and method of fertilization on fruit yield for HLB-affected trees. Macronutrients and micronutrients were applied at varying fertilization rates (0×, 1×, 2×, and 4×, of University of Florida guidelines). Root scans were done using minirhizotrons at 0 to 19.1 cm, 19.1 to 40.7 cm, 38.2 to 59.8 cm, and 57.3 to 78.9 cm soil depths. Results obtained from the study showed that root growth and distribution were greater in 0 to 19.1 cm than 19.1 to 40.7 cm to 57.3 to 78.9 cm soil depths. Thus, root growth decreased (P < 0.0004) with increasing soil depth due to variation in nutrient availability for tree uptake. Increased nutrient availability at occurrence of physiological processes in citrus trees also influenced root growth and distribution, resulting in root growth flushes in the months of Nov to early Feb and Jul to early Aug. Fruit yield was significantly different between treatments in 2 of the 4 years of the study (P = 0.001 and P = 0.003), and largely ascribed to soil fertilization of micronutrients compared with foliar. Therefore, at higher fertilization rates, particularly via soil application, nutrient availability was increased, thus promoting root growth and distribution and fruit yield in HLB-affected orange trees.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"212 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138621395","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/hortsci17350-23
W. Chueakhunthod, A. Khairum, Piyangkoon Jaukwon, Theerawat Chantakot, Tanandorn Woramit, S. Hualsawat, P.A. Tantasawat
To reveal the applicability of sequence-related amplified polymorphism (SRAP) and target region amplification polymorphism (TRAP) markers to mutant genotyping and marker identification for resistance to black rot (Phytophthora palmivora) in orchids (Dendrobium sp. ‘Earsakul’), we fingerprinted four nonmutagenized controls and 12 black rot-resistant mutants obtained with in vitro sodium azide (NaN3) and ethyl methanesulfonate (EMS) mutagenesis and in vitro selection using culture filtrate of P. palmivora. Each of the 20 SRAP and TRAP primer combinations yielded 375 and 384 scorable DNA bands, respectively, of which 94 (24.42%) and 88 (22.91%) were polymorphic, respectively. Mantel’s test cophenetic correlation coefficients of SRAP, TRAP, and SRAP/TRAP were 0.750, 0.921, and 0.861, respectively, indicating the efficiency of these markers, especially TRAP and SRAP/TRAP, for Dendrobium sp. ‘Earsakul’ mutant characterization. Moreover, the correlations between the matrices of cophenetic correlation values for the dendrograms of SRAP with TRAP, SRAP with SRAP/TRAP, and TRAP with SRAP/TRAP were 0.399, 0.566, and 0.793, respectively, and the dendrograms based on SRAP vs. TRAP and SRAP vs. SRAP/TRAP, with lower correlations, had more variations, i.e., the number of clusters, the members of clusters, and the placement of the materials, than the ones based on TRAP vs. SRAP/TRAP. Among the three dendrograms, all nonmutagenized controls were clustered together, whereas all the highly resistant and the most resistant mutants were distributed separately as individuals. Interestingly, the four SRAP and TRAP markers were significantly associated with black rot resistance. Overall, our results will be useful for facilitating future Dendrobium sp. ‘Earsakul’ breeding programs.
{"title":"Sequence-related Amplified Polymorphism and Target Region Amplification Polymorphism Markers-based Profiling of Sodium Azide and Ethyl Methanesulfonate-derived Black Rot-resistant Dendrobium sp. ‘Earsakul’ Mutants from In Vitro Mutagenesis and Selection","authors":"W. Chueakhunthod, A. Khairum, Piyangkoon Jaukwon, Theerawat Chantakot, Tanandorn Woramit, S. Hualsawat, P.A. Tantasawat","doi":"10.21273/hortsci17350-23","DOIUrl":"https://doi.org/10.21273/hortsci17350-23","url":null,"abstract":"To reveal the applicability of sequence-related amplified polymorphism (SRAP) and target region amplification polymorphism (TRAP) markers to mutant genotyping and marker identification for resistance to black rot (Phytophthora palmivora) in orchids (Dendrobium sp. ‘Earsakul’), we fingerprinted four nonmutagenized controls and 12 black rot-resistant mutants obtained with in vitro sodium azide (NaN3) and ethyl methanesulfonate (EMS) mutagenesis and in vitro selection using culture filtrate of P. palmivora. Each of the 20 SRAP and TRAP primer combinations yielded 375 and 384 scorable DNA bands, respectively, of which 94 (24.42%) and 88 (22.91%) were polymorphic, respectively. Mantel’s test cophenetic correlation coefficients of SRAP, TRAP, and SRAP/TRAP were 0.750, 0.921, and 0.861, respectively, indicating the efficiency of these markers, especially TRAP and SRAP/TRAP, for Dendrobium sp. ‘Earsakul’ mutant characterization. Moreover, the correlations between the matrices of cophenetic correlation values for the dendrograms of SRAP with TRAP, SRAP with SRAP/TRAP, and TRAP with SRAP/TRAP were 0.399, 0.566, and 0.793, respectively, and the dendrograms based on SRAP vs. TRAP and SRAP vs. SRAP/TRAP, with lower correlations, had more variations, i.e., the number of clusters, the members of clusters, and the placement of the materials, than the ones based on TRAP vs. SRAP/TRAP. Among the three dendrograms, all nonmutagenized controls were clustered together, whereas all the highly resistant and the most resistant mutants were distributed separately as individuals. Interestingly, the four SRAP and TRAP markers were significantly associated with black rot resistance. Overall, our results will be useful for facilitating future Dendrobium sp. ‘Earsakul’ breeding programs.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"213 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138621392","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/hortsci17499-23
Kimberly Heagy, Melinda Knuth, J. Schultheis, T. Birdsell, Jason K. Ward
Pumpkins (Cucurbita sp.) are currently sold in retail commercial bins categorized based on fruit size. There are no standards for these fruit sizes, thus creating discrepancies across the industry. Furthermore, there is not a published partial budget analysis for pumpkin fruit yield based on plant area. An observational study was conducted to quantify and standardize the fruit sizes of pumpkins packed into commercial bins. These proposed standardized fruit sizes were then correlated to the expected fruit size and quantity of different plant areas to estimate the total commercial bin yield. Additionally, a partial budget analysis was conducted to calculate the greatest profit per hectare with the varying plant areas. Pumpkins from bins labeled medium, large, extra-large, and jumbo were hand-measured to determine the diameter, length, and weight. Based on a discriminate analysis, 20% of pumpkins were incorrectly sorted based on current practices. The proposed standard fruit diameters for each bin size are as follows: medium, 23.5 to 26.8 cm; large, 26.9 to 29.9 cm; extra-large, 30.0 to 33.6 cm; and jumbo, 33.7 to 35.5 cm. The results of a partial budget analysis showed that the most profitable plant spacing area is 0.9 m2 with a 1.5-m row width, which will earn $37,163/ha. Profit for pumpkin production is contingent on both fruit quantity and fruit size because these factors dictate the quantity and category of commercial bins. Growers should consider both metrics to optimize their operation.
{"title":"Using Partial Budgeting Analyses to Analyze Profitability of Commercial Pumpkin Production, Standardize Bin Size Categories, and Understand Bin Sorting Accuracy","authors":"Kimberly Heagy, Melinda Knuth, J. Schultheis, T. Birdsell, Jason K. Ward","doi":"10.21273/hortsci17499-23","DOIUrl":"https://doi.org/10.21273/hortsci17499-23","url":null,"abstract":"Pumpkins (Cucurbita sp.) are currently sold in retail commercial bins categorized based on fruit size. There are no standards for these fruit sizes, thus creating discrepancies across the industry. Furthermore, there is not a published partial budget analysis for pumpkin fruit yield based on plant area. An observational study was conducted to quantify and standardize the fruit sizes of pumpkins packed into commercial bins. These proposed standardized fruit sizes were then correlated to the expected fruit size and quantity of different plant areas to estimate the total commercial bin yield. Additionally, a partial budget analysis was conducted to calculate the greatest profit per hectare with the varying plant areas. Pumpkins from bins labeled medium, large, extra-large, and jumbo were hand-measured to determine the diameter, length, and weight. Based on a discriminate analysis, 20% of pumpkins were incorrectly sorted based on current practices. The proposed standard fruit diameters for each bin size are as follows: medium, 23.5 to 26.8 cm; large, 26.9 to 29.9 cm; extra-large, 30.0 to 33.6 cm; and jumbo, 33.7 to 35.5 cm. The results of a partial budget analysis showed that the most profitable plant spacing area is 0.9 m2 with a 1.5-m row width, which will earn $37,163/ha. Profit for pumpkin production is contingent on both fruit quantity and fruit size because these factors dictate the quantity and category of commercial bins. Growers should consider both metrics to optimize their operation.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"46 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138627108","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/hortsci16961-22
J. Slovin, Laura E. Dougherty
Knowledge of the genes underlying a given trait is highly useful for developing molecular markers for breeding and is the foundation for future genomic crop improvements. The cultivated strawberry, F. ×ananassa, is a valuable horticultural crop. Genome sequencing revealed that of the four diploid strawberry subgenomes contributing to the F. ×ananassa octoploid genome, the woodland strawberry, F. vesca, subgenome is dominant. Thus, F. vesca is an important system for determining gene function and should be used as a source of genetic diversity for F. ×ananassa breeding. Ethyl methanesulfonate mutagenesis of H4 F7-3, an inbred line of F. vesca, resulted in one M2 line that did not produce any strawberries over a 3-year period in the greenhouse. This line was named fruitless 1. The fruitless 1 phenotype results from a single gene recessive mutation. Microscopic characterization revealed that fruitless 1 failed to produce fruit because anthers fail to develop properly before meiosis, resulting in no pollen production. This report of fruitless 1 facilitates further studies of the line.
{"title":"Abnormal Pollen Development in the Fragaria vesca Mutant fruitless 1","authors":"J. Slovin, Laura E. Dougherty","doi":"10.21273/hortsci16961-22","DOIUrl":"https://doi.org/10.21273/hortsci16961-22","url":null,"abstract":"Knowledge of the genes underlying a given trait is highly useful for developing molecular markers for breeding and is the foundation for future genomic crop improvements. The cultivated strawberry, F. ×ananassa, is a valuable horticultural crop. Genome sequencing revealed that of the four diploid strawberry subgenomes contributing to the F. ×ananassa octoploid genome, the woodland strawberry, F. vesca, subgenome is dominant. Thus, F. vesca is an important system for determining gene function and should be used as a source of genetic diversity for F. ×ananassa breeding. Ethyl methanesulfonate mutagenesis of H4 F7-3, an inbred line of F. vesca, resulted in one M2 line that did not produce any strawberries over a 3-year period in the greenhouse. This line was named fruitless 1. The fruitless 1 phenotype results from a single gene recessive mutation. Microscopic characterization revealed that fruitless 1 failed to produce fruit because anthers fail to develop properly before meiosis, resulting in no pollen production. This report of fruitless 1 facilitates further studies of the line.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":" 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138612693","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/hortsci17361-23
Jun-Yao Yu, Chin-Mu Chen
Chrysanthemum ‘Bai Tian Xing’, ‘Huang Ching Chin’, ‘Pink Pearl’, and ‘NCHU-001’ plants were preheated at 35 °C for 24 hours to induce heat tolerance. The recently fully expanded leaves were detached, kept in a moist Ziploc bag, and then subjected to 35, 40, 45, 47.5, 50, 52.5, 55, 60, or 65 °C for 20 minutes. After dark-acclimatized at room temperature for 30 minutes, leaves were measured for Fv/Fm value with a chlorophyll fluorescence parameter. Results showed that ‘Bai Tian Xing’ had the highest critical (Tcrit) and midpoint temperature (Tmid). Mean Tcrit and Tmid were shown to be 47 and 50 °C, respectively, and Tmid gave greater distinguishment of Fv/Fm value among cultivars. Plants of four cultivars were acclimatized at 15 to 40 °C for 3 days and 35 °C being the most effective temperature to induce a heat-tolerant response in chrysanthemum. Required inducing time to reach a stable leaf Fv/Fm value ranged from 4.6 to 11.1 hours among cultivars. All cultivars had similar required time to reach visible bud between summer and autumn crops (except NCHU-001), but all had delayed flowering in the summer crop. There is a negative linear relationship between flowering heat delay and leaf Fv/Fm value (R2 = 0.93). Progenies from reciprocal crossing of ‘Bai Tian Xing’ × ‘NCHU-001’ and ‘Huang Ching Chin’ × ‘Pink Pearl’ were also subjected to treatments for Fv/Fm measurements and observed for time to flowering in the summer crop. All combinations showed negative linear relationship between time to flowering and leaf Fv/Fm value (R2 = 0.70–0.87). Two plants, 109-W001Y and 109-W003Pi, showed early flowering habit and good flower performance under heat conditions were selected. All four cultivars and the two selected lines were measured for photosynthetic parameters under day/night temperatures of 35/30 or 25/20 °C in growth chambers. All cultivars and lines showed decreased net photosynthetic rate and dark respiration rate under 35/30 °C when compared with 25/20 °C. Relatively higher net photosynthetic rate and lower dark respiration rate in ‘Bai Tian Xing’, ‘109-W001Y’, and ‘109-W003Pi’ under 35/30 °C, when compared with the other three cultivars, might have contributed to better flowering performance in the summer.
{"title":"Chlorophyll Fluorescence Parameter as a Tool in Selecting Heat-tolerant Summer-flowering Chrysanthemum (Dendranthema ×grandiflorum)","authors":"Jun-Yao Yu, Chin-Mu Chen","doi":"10.21273/hortsci17361-23","DOIUrl":"https://doi.org/10.21273/hortsci17361-23","url":null,"abstract":"Chrysanthemum ‘Bai Tian Xing’, ‘Huang Ching Chin’, ‘Pink Pearl’, and ‘NCHU-001’ plants were preheated at 35 °C for 24 hours to induce heat tolerance. The recently fully expanded leaves were detached, kept in a moist Ziploc bag, and then subjected to 35, 40, 45, 47.5, 50, 52.5, 55, 60, or 65 °C for 20 minutes. After dark-acclimatized at room temperature for 30 minutes, leaves were measured for Fv/Fm value with a chlorophyll fluorescence parameter. Results showed that ‘Bai Tian Xing’ had the highest critical (Tcrit) and midpoint temperature (Tmid). Mean Tcrit and Tmid were shown to be 47 and 50 °C, respectively, and Tmid gave greater distinguishment of Fv/Fm value among cultivars. Plants of four cultivars were acclimatized at 15 to 40 °C for 3 days and 35 °C being the most effective temperature to induce a heat-tolerant response in chrysanthemum. Required inducing time to reach a stable leaf Fv/Fm value ranged from 4.6 to 11.1 hours among cultivars. All cultivars had similar required time to reach visible bud between summer and autumn crops (except NCHU-001), but all had delayed flowering in the summer crop. There is a negative linear relationship between flowering heat delay and leaf Fv/Fm value (R2 = 0.93). Progenies from reciprocal crossing of ‘Bai Tian Xing’ × ‘NCHU-001’ and ‘Huang Ching Chin’ × ‘Pink Pearl’ were also subjected to treatments for Fv/Fm measurements and observed for time to flowering in the summer crop. All combinations showed negative linear relationship between time to flowering and leaf Fv/Fm value (R2 = 0.70–0.87). Two plants, 109-W001Y and 109-W003Pi, showed early flowering habit and good flower performance under heat conditions were selected. All four cultivars and the two selected lines were measured for photosynthetic parameters under day/night temperatures of 35/30 or 25/20 °C in growth chambers. All cultivars and lines showed decreased net photosynthetic rate and dark respiration rate under 35/30 °C when compared with 25/20 °C. Relatively higher net photosynthetic rate and lower dark respiration rate in ‘Bai Tian Xing’, ‘109-W001Y’, and ‘109-W003Pi’ under 35/30 °C, when compared with the other three cultivars, might have contributed to better flowering performance in the summer.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"129 ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138615221","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/hortsci17415-23
Emilio Suarez, Pratiksha Agrawal, L. G. Izzo, Celina Gómez
The main objective of this study was to characterize intumescence injury of three susceptible tomato cultivars grown in a greenhouse or indoors using two types of soilless culture systems. Plants of cultivars Maxifort, Camaro, and Patio were grown in either an indoor environment with broadband white and red light-emitting diode (LED) fixtures providing a daily light integral (DLI) of 12.7 mol·m−2·day−1 [photosynthetic photon flux density (PPFD) of 220 ± 3 µmol·m−2·s−1 for 16 h·d−1] or in a glass-glazed greenhouse with supplemental lighting provided by high-pressure sodium lamps that delivered a PPFD of ∼150 µmol·m−2·s−1. Plants were grown using deep-water culture hydroponic systems or containers with a peat-based substrate. The growing environment had a larger effect on intumescence incidence and severity than the growing system, likely due to differences in ultraviolet radiation (100 to 400 nm), but other factors such as day/night temperature and relative humidity (RH), could have affected the response. Across cultivars, the probability of developing intumescence was higher indoors (≥91%) than in the greenhouse. Indoor-grown plants also developed symptoms of the disorder from 2 to 6 days earlier than those in the greenhouse. Similarly, intumescence incidence was higher in plants from all cultivars grown indoors than in the greenhouse, but differences between the two environments were generally greater for Patio and Camaro than for Maxifort, which was the most susceptible cultivar. Greenhouse conditions were more conducive to active plant growth. For example, plants in the greenhouse were more than 2 times taller and had at least 12 times greater leaf area than those indoors, which resulted in large differences in shoot dry mass. However, environmental effects on intumescence response also contributed to differences in growth, as plants that were most affected by the disorder experienced severe leaf abscission and/or senescence. Our overall findings show that intumescence is greatly affected by the production environment, but injuries are likely to change based on genetic susceptibility.
{"title":"Intumescence Response by Tomato Plants Grown in a Greenhouse or Indoors Using Two Types of Soilless Culture Systems","authors":"Emilio Suarez, Pratiksha Agrawal, L. G. Izzo, Celina Gómez","doi":"10.21273/hortsci17415-23","DOIUrl":"https://doi.org/10.21273/hortsci17415-23","url":null,"abstract":"The main objective of this study was to characterize intumescence injury of three susceptible tomato cultivars grown in a greenhouse or indoors using two types of soilless culture systems. Plants of cultivars Maxifort, Camaro, and Patio were grown in either an indoor environment with broadband white and red light-emitting diode (LED) fixtures providing a daily light integral (DLI) of 12.7 mol·m−2·day−1 [photosynthetic photon flux density (PPFD) of 220 ± 3 µmol·m−2·s−1 for 16 h·d−1] or in a glass-glazed greenhouse with supplemental lighting provided by high-pressure sodium lamps that delivered a PPFD of ∼150 µmol·m−2·s−1. Plants were grown using deep-water culture hydroponic systems or containers with a peat-based substrate. The growing environment had a larger effect on intumescence incidence and severity than the growing system, likely due to differences in ultraviolet radiation (100 to 400 nm), but other factors such as day/night temperature and relative humidity (RH), could have affected the response. Across cultivars, the probability of developing intumescence was higher indoors (≥91%) than in the greenhouse. Indoor-grown plants also developed symptoms of the disorder from 2 to 6 days earlier than those in the greenhouse. Similarly, intumescence incidence was higher in plants from all cultivars grown indoors than in the greenhouse, but differences between the two environments were generally greater for Patio and Camaro than for Maxifort, which was the most susceptible cultivar. Greenhouse conditions were more conducive to active plant growth. For example, plants in the greenhouse were more than 2 times taller and had at least 12 times greater leaf area than those indoors, which resulted in large differences in shoot dry mass. However, environmental effects on intumescence response also contributed to differences in growth, as plants that were most affected by the disorder experienced severe leaf abscission and/or senescence. Our overall findings show that intumescence is greatly affected by the production environment, but injuries are likely to change based on genetic susceptibility.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"13 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138624251","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/hortsci17230-23
Amy Fulcher, Alicia L. Rihn, Laura A. Warner, A. LeBude, Susan Schexnayder, J. Altland, Natalie Bumgarner, S. C. Marble, Lloyd Nackley, Marco Palma, Margarita Velandia, Heping Zhu, Hao Gan, James S. Owen
US nurseries are experiencing a workforce shortage that is expected to intensify. A mixed-mode survey of decision-makers representing the US nursery industry was conducted in 2021. The survey assessed practices used in 2020 to elicit a better understanding of nursery approaches to the challenges presented by persistent labor scarcity. We compare our results with survey data collected ∼15 years earlier at container nurseries. Survey responses revealed that nurseries were undertaking strategies that aimed to improve production efficiency, better recruit and retain employees, and secure other sources of labor to overcome this shortage. Specifically, more than 65% of surveyed US nurseries increased worker wages, and more than 55% of respondents adopted automation to address the labor shortage. Strategies in use by ≥23% of respondents may limit future growth or jeopardize long-term nursery survival. These include diversifying tasks of current employees, reducing production of labor-intensive plants, or delaying expansion plans. Survey results suggested that production tasks excluding irrigation were on average 31% automated or mechanized at container nurseries, an increase from 16% during the prior survey. Field nurseries were 35% automated or mechanized in 2020. Newly developed or yet-to-be developed automated and mechanized technology (AMT) that decision-makers perceive as being helpful were reported. This article explores linkages between nursery characteristics and AMT adoption and highlights research and extension programming initiatives that are needed to help growers make informed decisions regarding adopting automation.
{"title":"Overcoming the Nursery Industry Labor Shortage: A Survey of Strategies to Adapt to a Reduced Workforce and Automation and Mechanization Technology Adoption Levels","authors":"Amy Fulcher, Alicia L. Rihn, Laura A. Warner, A. LeBude, Susan Schexnayder, J. Altland, Natalie Bumgarner, S. C. Marble, Lloyd Nackley, Marco Palma, Margarita Velandia, Heping Zhu, Hao Gan, James S. Owen","doi":"10.21273/hortsci17230-23","DOIUrl":"https://doi.org/10.21273/hortsci17230-23","url":null,"abstract":"US nurseries are experiencing a workforce shortage that is expected to intensify. A mixed-mode survey of decision-makers representing the US nursery industry was conducted in 2021. The survey assessed practices used in 2020 to elicit a better understanding of nursery approaches to the challenges presented by persistent labor scarcity. We compare our results with survey data collected ∼15 years earlier at container nurseries. Survey responses revealed that nurseries were undertaking strategies that aimed to improve production efficiency, better recruit and retain employees, and secure other sources of labor to overcome this shortage. Specifically, more than 65% of surveyed US nurseries increased worker wages, and more than 55% of respondents adopted automation to address the labor shortage. Strategies in use by ≥23% of respondents may limit future growth or jeopardize long-term nursery survival. These include diversifying tasks of current employees, reducing production of labor-intensive plants, or delaying expansion plans. Survey results suggested that production tasks excluding irrigation were on average 31% automated or mechanized at container nurseries, an increase from 16% during the prior survey. Field nurseries were 35% automated or mechanized in 2020. Newly developed or yet-to-be developed automated and mechanized technology (AMT) that decision-makers perceive as being helpful were reported. This article explores linkages between nursery characteristics and AMT adoption and highlights research and extension programming initiatives that are needed to help growers make informed decisions regarding adopting automation.","PeriodicalId":13140,"journal":{"name":"Hortscience","volume":"11 6","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138609696","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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