Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0076
Neda Zuļģe, E. Rubauskis, I. Missa, Daina Reveliòa, I. Borisova
Abstract The negative influence of pathogens on plant development is well known. However, the negative impact depends on various factors: cultivar and rootstock resistance, nutrition, the environment, the virulence, and concentration of pathogens in the plant tissue. The evaluation of apple chlorotic leaf spot virus (ACLSV) influence on apple tree growth and production was performed at Institute of Horticulture (LatHort) from 2012 to 2020. Virus-free and ACLSV-infected trees from the traditional cultivar ‘Antonovka’ and new scab resistant cultivar ‘Gita’ were evaluated on dwarfing rootstock B.396. The presence of four common apple viruses (apple mosaic virus (ApMV), ACLSV, apple stem grooving virus (ASGV), apple stem pitting virus (ASPV)) was assayed in the planting year and repeated at the end of the study period. The vigour of planting material, growth, yield, and yield efficiency were compared between virus negative and ACLSV-infected trees. During eight growing seasons (2013–2020), no statistically significant negative impact of ACLSV infection on tree growth or yield was observed for the cultivars. A larger canopy volume was observed for ACLSV-infected trees (p = 0.01), but the cumulative yield per canopy volume was equivalent between virus-negative trees and ACLSV-infected trees (p = 0.07).
{"title":"Evaluation of Apple Chlorotic Leaf Spot Virus Impact on Fruit Yield and Vegetative Growth in Apple Cultivars ‘Antonovka’ and ‘Gita’","authors":"Neda Zuļģe, E. Rubauskis, I. Missa, Daina Reveliòa, I. Borisova","doi":"10.2478/prolas-2022-0076","DOIUrl":"https://doi.org/10.2478/prolas-2022-0076","url":null,"abstract":"Abstract The negative influence of pathogens on plant development is well known. However, the negative impact depends on various factors: cultivar and rootstock resistance, nutrition, the environment, the virulence, and concentration of pathogens in the plant tissue. The evaluation of apple chlorotic leaf spot virus (ACLSV) influence on apple tree growth and production was performed at Institute of Horticulture (LatHort) from 2012 to 2020. Virus-free and ACLSV-infected trees from the traditional cultivar ‘Antonovka’ and new scab resistant cultivar ‘Gita’ were evaluated on dwarfing rootstock B.396. The presence of four common apple viruses (apple mosaic virus (ApMV), ACLSV, apple stem grooving virus (ASGV), apple stem pitting virus (ASPV)) was assayed in the planting year and repeated at the end of the study period. The vigour of planting material, growth, yield, and yield efficiency were compared between virus negative and ACLSV-infected trees. During eight growing seasons (2013–2020), no statistically significant negative impact of ACLSV infection on tree growth or yield was observed for the cultivars. A larger canopy volume was observed for ACLSV-infected trees (p = 0.01), but the cumulative yield per canopy volume was equivalent between virus-negative trees and ACLSV-infected trees (p = 0.07).","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83586556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0074
S. Kodors, G. Lācis, I. Moročko‐Bičevska, Imants Zarembo, O. Sokolova, T. Bartulsons, I. Apeināns, Vitālijs Žukovs
Abstract Modern reviews of challenges related to deep learning application in agriculture mention restricted access to open datasets with high-resolution natural images taken in field conditions. Therefore, artificial intelligence solutions trained on these datasets containing low-resolution images and disease symptoms in the advanced stage are not suitable for early detection of plant diseases. The study aims to train a convolutional neural network for apple scab detection in an early stage of disease development. In this study a dataset was collected and used to develop a convolutional neural network based on the sliding-window method. The convolutional neural network was trained using the transfer-learning approach and MobileNetV2 architecture tuned on for embedded devices. The quality analysis in laboratory conditions showed the following accuracy results: F1 score 0.96 and Cohen’s kappa 0.94; and the occlusion maps — correct classification features.
{"title":"Apple Scab Detection in the Early Stage of Disease Using a Convolutional Neural Network","authors":"S. Kodors, G. Lācis, I. Moročko‐Bičevska, Imants Zarembo, O. Sokolova, T. Bartulsons, I. Apeināns, Vitālijs Žukovs","doi":"10.2478/prolas-2022-0074","DOIUrl":"https://doi.org/10.2478/prolas-2022-0074","url":null,"abstract":"Abstract Modern reviews of challenges related to deep learning application in agriculture mention restricted access to open datasets with high-resolution natural images taken in field conditions. Therefore, artificial intelligence solutions trained on these datasets containing low-resolution images and disease symptoms in the advanced stage are not suitable for early detection of plant diseases. The study aims to train a convolutional neural network for apple scab detection in an early stage of disease development. In this study a dataset was collected and used to develop a convolutional neural network based on the sliding-window method. The convolutional neural network was trained using the transfer-learning approach and MobileNetV2 architecture tuned on for embedded devices. The quality analysis in laboratory conditions showed the following accuracy results: F1 score 0.96 and Cohen’s kappa 0.94; and the occlusion maps — correct classification features.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85955500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0077
I. Grāvīte
Abstract Cold resistance of fruit tree buds is very important. Climate change brings unstable winters, and the temperature often fluctuates and creates many problems in fruit growing. Research on bud cold damage was conducted during three years (2019–2021) at the Institute of Horticulture. Three Latvian plum cultivars, ‘Ance’, ‘Adelyn’, and ‘Sonora’, were studied, while cultivar ‘Jubileum’ was used as a control. This study aimed to determine the cold resistance of flower buds and vegetative buds of plum cultivars after the deep dormancy period. Evaluation of buds was done on one-year-old shoots and spurs. Evaluation of cold damage on flower buds and vegetative buds was done after the deep dormancy period: in February 2019 and at the end of January 2020 and 2021, after keeping the buds for a limited time in temperatures thresholds of –20 °C, –25 °C, –30 °C, –35 °C in alternating climate chambers. The results showed significant differences among cultivars, years, and between branch types. Vegetative buds for all cultivars were without significant cold damage. Up to –30 °C wood browning was observed near the base of buds. A significant amount of flower bud damage (up to 100%) was observed in 2020, in a temperature threshold until –30 °C for both types of branches. The most durable cultivars were ‘Ance’ and ‘Adelyn’ (up to –25 °C, bud survival was near 100%) all three years. ‘Jubileum’ had the most vulnerable flower buds. The lowest low-temperature damage for all cultivars was in 2021. For one-year-old shoots, bud damage only occurred at –35 °C for all cultivars all years.
{"title":"Cold Resistance of Flower Buds of Latvian Plum Cultivars","authors":"I. Grāvīte","doi":"10.2478/prolas-2022-0077","DOIUrl":"https://doi.org/10.2478/prolas-2022-0077","url":null,"abstract":"Abstract Cold resistance of fruit tree buds is very important. Climate change brings unstable winters, and the temperature often fluctuates and creates many problems in fruit growing. Research on bud cold damage was conducted during three years (2019–2021) at the Institute of Horticulture. Three Latvian plum cultivars, ‘Ance’, ‘Adelyn’, and ‘Sonora’, were studied, while cultivar ‘Jubileum’ was used as a control. This study aimed to determine the cold resistance of flower buds and vegetative buds of plum cultivars after the deep dormancy period. Evaluation of buds was done on one-year-old shoots and spurs. Evaluation of cold damage on flower buds and vegetative buds was done after the deep dormancy period: in February 2019 and at the end of January 2020 and 2021, after keeping the buds for a limited time in temperatures thresholds of –20 °C, –25 °C, –30 °C, –35 °C in alternating climate chambers. The results showed significant differences among cultivars, years, and between branch types. Vegetative buds for all cultivars were without significant cold damage. Up to –30 °C wood browning was observed near the base of buds. A significant amount of flower bud damage (up to 100%) was observed in 2020, in a temperature threshold until –30 °C for both types of branches. The most durable cultivars were ‘Ance’ and ‘Adelyn’ (up to –25 °C, bud survival was near 100%) all three years. ‘Jubileum’ had the most vulnerable flower buds. The lowest low-temperature damage for all cultivars was in 2021. For one-year-old shoots, bud damage only occurred at –35 °C for all cultivars all years.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82636705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0073
E. Kaufmane, S. Ruisa, K. Kārkliņa
Abstract The aim of the trial was to determine the optimal propagation methods for three Japanese quince cultivars. Rooting trials with cultivars ‘Darius’, ‘Rasa’, and ‘Rondo’ were conducted in 2017–2019 in a greenhouse, to investigate the rooting and shoot quality of softwood cuttings, using different treatments. At the beginning of fruit production, growth and amount of the first yield was evaluated depending on propagation method. Softwood cuttings of Japanese quince rooted well (average 82–93%) in a greenhouse with heated substrate and partly automated temperature and moisture control, in spite of different weather conditions during three vegetation periods. The best results for rooting were found for cultivar ‘Rondo’. On average, better results of rooting for all cultivars were obtained when cuttings were soaked in indolylbutiric acid solution and trichodermin was added to the substrate. Significant differences in length and diameter of the bush shoots found between years for both propagation methods and also between years for one type of propagation. On average, microproagated plants had the highest shoot length. After evaluating the first yield, no significant differences were found between cultivars during the first two trial years, but micro-propagated plants had significantly higher yield per bush.
{"title":"Results of Propagation of Three Cultivars of Japanese Quince (Chaenomeles Japonica)","authors":"E. Kaufmane, S. Ruisa, K. Kārkliņa","doi":"10.2478/prolas-2022-0073","DOIUrl":"https://doi.org/10.2478/prolas-2022-0073","url":null,"abstract":"Abstract The aim of the trial was to determine the optimal propagation methods for three Japanese quince cultivars. Rooting trials with cultivars ‘Darius’, ‘Rasa’, and ‘Rondo’ were conducted in 2017–2019 in a greenhouse, to investigate the rooting and shoot quality of softwood cuttings, using different treatments. At the beginning of fruit production, growth and amount of the first yield was evaluated depending on propagation method. Softwood cuttings of Japanese quince rooted well (average 82–93%) in a greenhouse with heated substrate and partly automated temperature and moisture control, in spite of different weather conditions during three vegetation periods. The best results for rooting were found for cultivar ‘Rondo’. On average, better results of rooting for all cultivars were obtained when cuttings were soaked in indolylbutiric acid solution and trichodermin was added to the substrate. Significant differences in length and diameter of the bush shoots found between years for both propagation methods and also between years for one type of propagation. On average, microproagated plants had the highest shoot length. After evaluating the first yield, no significant differences were found between cultivars during the first two trial years, but micro-propagated plants had significantly higher yield per bush.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87772988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0082
K. Kampuss, Daina Šarkovska
Abstract Although golden currant has been grown in Latvia for several decades, mainly as ornamental plant, there is little experience on the most suitable cultivation systems for berry production. Two cultivars of golden currant — ‘Laila’ and ‘Uzbekistanskaya Krupnoplodnaya’, were planted in 2017 in two cultivation systems — vertical trellis and shrub form and assessed in the first two seasons with harvest. In addition, plots with and without organic mulch were established in the shrub system. The aim of the study was to investigate the growth, development and yield of golden currant depending on the cultivation system. All plants bloomed abundantly and practically at the same time in both years, while no significant differences were found between cultivation systems and cultivars. The annual growth of shoots in 2020 was significantly affected by the cultivation system — on average 0.66 m in the trellis system, 0.41 m in the shrub system in mulched plots, and 0.43 m in unmulched plots. Cultivar ‘Laila’ tended to produce longer shoots (average 0.51 m) than the ‘Uzbekistanskaya Krupnoplodnaya’ (average 0.47 m). The yield was low because of poor fruit set and did not significantly differ between cultivar and cultivation systems, though cultivar ‘Laila’ and shrub systems still had higher yields.
{"title":"Growth, Development and Yield of Golden Currant (Ribes Aureum Pursh.) Depending on Cultivation System","authors":"K. Kampuss, Daina Šarkovska","doi":"10.2478/prolas-2022-0082","DOIUrl":"https://doi.org/10.2478/prolas-2022-0082","url":null,"abstract":"Abstract Although golden currant has been grown in Latvia for several decades, mainly as ornamental plant, there is little experience on the most suitable cultivation systems for berry production. Two cultivars of golden currant — ‘Laila’ and ‘Uzbekistanskaya Krupnoplodnaya’, were planted in 2017 in two cultivation systems — vertical trellis and shrub form and assessed in the first two seasons with harvest. In addition, plots with and without organic mulch were established in the shrub system. The aim of the study was to investigate the growth, development and yield of golden currant depending on the cultivation system. All plants bloomed abundantly and practically at the same time in both years, while no significant differences were found between cultivation systems and cultivars. The annual growth of shoots in 2020 was significantly affected by the cultivation system — on average 0.66 m in the trellis system, 0.41 m in the shrub system in mulched plots, and 0.43 m in unmulched plots. Cultivar ‘Laila’ tended to produce longer shoots (average 0.51 m) than the ‘Uzbekistanskaya Krupnoplodnaya’ (average 0.47 m). The yield was low because of poor fruit set and did not significantly differ between cultivar and cultivation systems, though cultivar ‘Laila’ and shrub systems still had higher yields.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89876882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0072
D. Feldmane, D. Dēķena, E. Cirša
Abstract The aim of the study was to characterise the variability of flower bud frost tolerance, self-pollination and fruit quality in Latvian local sour cherries; and to select the most promising aces-sions. Data on fruit set after self-pollination, frost tolerance of flower buds, fruit and stone weight, stem retention force and soluble solid content were collected for 29 accessions of local cherries in 2016–2019. Sour cherry cv. ‘Latvijas Zemais’ clones no. 64, D7, and 4 were the most promising for fruit processing; clones no. 62, 65, Matkules, and Lietuvas were promising as pollinators due to tolerance to spring frosts and high level of fruit set after self-pollination, and cv. ‘Latvijas Zemais’ clones Eglīša, Piïkas 3, Matkules, and Dumbrava had relatively high fruit weight and soluble solid content for fresh consumption. ‘Latvijas Zemais’ clone no. 62 was superior with stable fruit set after self-pollination (21.54%), cold resistant flower buds (89.5%) and high proportion of fruit flesh (93.8 %), clone no. 52 had high soluble solid content (18.88 Brix) and clone Eglīša had large fruit (5.56 g). The highest contribution to variability was provided by fruit weight, stone weight, and soluble solid content, which explained 79.90% of total variability.
{"title":"Frost Tolerance of Flower Buds, Self-Pollination and Fruit Quality Traits in Local Sour Cherries of Latvia","authors":"D. Feldmane, D. Dēķena, E. Cirša","doi":"10.2478/prolas-2022-0072","DOIUrl":"https://doi.org/10.2478/prolas-2022-0072","url":null,"abstract":"Abstract The aim of the study was to characterise the variability of flower bud frost tolerance, self-pollination and fruit quality in Latvian local sour cherries; and to select the most promising aces-sions. Data on fruit set after self-pollination, frost tolerance of flower buds, fruit and stone weight, stem retention force and soluble solid content were collected for 29 accessions of local cherries in 2016–2019. Sour cherry cv. ‘Latvijas Zemais’ clones no. 64, D7, and 4 were the most promising for fruit processing; clones no. 62, 65, Matkules, and Lietuvas were promising as pollinators due to tolerance to spring frosts and high level of fruit set after self-pollination, and cv. ‘Latvijas Zemais’ clones Eglīša, Piïkas 3, Matkules, and Dumbrava had relatively high fruit weight and soluble solid content for fresh consumption. ‘Latvijas Zemais’ clone no. 62 was superior with stable fruit set after self-pollination (21.54%), cold resistant flower buds (89.5%) and high proportion of fruit flesh (93.8 %), clone no. 52 had high soluble solid content (18.88 Brix) and clone Eglīša had large fruit (5.56 g). The highest contribution to variability was provided by fruit weight, stone weight, and soluble solid content, which explained 79.90% of total variability.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88833179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0086
V. Laugale, I. Krasnova, L. Lepse
Abstract Gooseberries are very popular in home gardens and have a long growing history in Latvia, although nowadays they are not among the most widely grown commercial berry crops. Growing was initiated by some enthusiastic breeders during the previous century, who developed many cultivars. Unfortunately, some part of this breeding material has already disappeared. Several expeditions were organised to collect still available genotypes. Plants of the obtained material were propagated and planted at the collections of Institute of Horticulture. During 2019–2021, to select the most valuable material for preservation in the National Genetic Resources Collection, an evaluation of the collected material as well as of cultivars of Latvian origin, was carried out. In total 23 genotypes were evaluated. Plant morphological, phenological, yield and fruit quality traits as well as resistance to pests and diseases and biochemical value were investigated. Evaluated genotypes showed great variability within the evaluated traits. GEN 693, GEN Drudze, GEN 88A, GEN 774 and Nr. 269 were selected as the most valuable and diverse genotypes from the collected and preserved breeding material. The Latvia origin cultivars: ‘Avenīte’, ‘Kuršu Dzintars’, ‘Maija’, ‘Mazērkšíotā’, and ‘Rita’, were selected for preservation in the recovered core collection.
{"title":"Characterisation of Latvian Gooseberry Genetic Resources","authors":"V. Laugale, I. Krasnova, L. Lepse","doi":"10.2478/prolas-2022-0086","DOIUrl":"https://doi.org/10.2478/prolas-2022-0086","url":null,"abstract":"Abstract Gooseberries are very popular in home gardens and have a long growing history in Latvia, although nowadays they are not among the most widely grown commercial berry crops. Growing was initiated by some enthusiastic breeders during the previous century, who developed many cultivars. Unfortunately, some part of this breeding material has already disappeared. Several expeditions were organised to collect still available genotypes. Plants of the obtained material were propagated and planted at the collections of Institute of Horticulture. During 2019–2021, to select the most valuable material for preservation in the National Genetic Resources Collection, an evaluation of the collected material as well as of cultivars of Latvian origin, was carried out. In total 23 genotypes were evaluated. Plant morphological, phenological, yield and fruit quality traits as well as resistance to pests and diseases and biochemical value were investigated. Evaluated genotypes showed great variability within the evaluated traits. GEN 693, GEN Drudze, GEN 88A, GEN 774 and Nr. 269 were selected as the most valuable and diverse genotypes from the collected and preserved breeding material. The Latvia origin cultivars: ‘Avenīte’, ‘Kuršu Dzintars’, ‘Maija’, ‘Mazērkšíotā’, and ‘Rita’, were selected for preservation in the recovered core collection.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83718662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0063
I. Hjalmarsson
Abstract Some 35 cultivars of Fragaria are preserved in the Swedish National Gene Bank for vegetatively propagated crops, which opened in 2016. The genebank includes a field collection in Alnarp, southern Sweden, and a back-up collection of virus-free plants at the Swedish Elite Plant Station. Here we document how the cultivars, the so-called mandate cultivars, were selected. Swedish origin was the primary criteria used in the selection process. In this category cultivars from historic Swedish breeding programmes are of particular interest. During 80 years, starting in the 1920s and ending in the late 1990s, 16 strawberries including three Fragaria × vescana hybrids were developed by Swedish breeders. Unfortunately, for three of these the accessions in the genebank are uncertain and four have not yet been recovered. The 16 cultivars bred in Sweden are presented with their year of introduction, parentage and short descriptions. Additionally, we also briefly describe local cultivars of strawberries and wild strawberries. Another category of mandate cultivars are foreign cultivars with a growing tradition in Sweden dating back to before 1966. Their age, country of origin, and importance for Swedish cultivation are discussed.
{"title":"Strawberry Cultivars Preserved in the Swedish National Gene Bank","authors":"I. Hjalmarsson","doi":"10.2478/prolas-2022-0063","DOIUrl":"https://doi.org/10.2478/prolas-2022-0063","url":null,"abstract":"Abstract Some 35 cultivars of Fragaria are preserved in the Swedish National Gene Bank for vegetatively propagated crops, which opened in 2016. The genebank includes a field collection in Alnarp, southern Sweden, and a back-up collection of virus-free plants at the Swedish Elite Plant Station. Here we document how the cultivars, the so-called mandate cultivars, were selected. Swedish origin was the primary criteria used in the selection process. In this category cultivars from historic Swedish breeding programmes are of particular interest. During 80 years, starting in the 1920s and ending in the late 1990s, 16 strawberries including three Fragaria × vescana hybrids were developed by Swedish breeders. Unfortunately, for three of these the accessions in the genebank are uncertain and four have not yet been recovered. The 16 cultivars bred in Sweden are presented with their year of introduction, parentage and short descriptions. Additionally, we also briefly describe local cultivars of strawberries and wild strawberries. Another category of mandate cultivars are foreign cultivars with a growing tradition in Sweden dating back to before 1966. Their age, country of origin, and importance for Swedish cultivation are discussed.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85936397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0075
O. Sokolova, I. Moročko‐Bičevska
Abstract Apple scab caused by the heterothallic ascomycetous fungus Venturia inaequalis is one of the most severe diseases in apple-growing regions worldwide. Annual sexual reproduction of the pathogen ensures the formation of populations with high variability and better adaptability to resistant cultivars. The present study aimed to assess the virulence of the V. inaequalis population in the experimental orchard where introduction, evaluation and breeding of apple cultivars are carried out, and the apple germplasm collection of Latvia is located. Fifteen differential Malus genotypes, obtained within the international Vinquest initiative, were planted in 2016 in the germplasm collection sector of the orchard in five blocks, each containing one tree of each geno-type. In 2017–2021, apple scab symptoms on the leaves were scored according to the methodology used in the Vinquest network. The disease severity increased with each vegetation season, and more genotypes were affected, reaching the maximum in 2021 and clearly indicating the infection source build-up and pathogen’s adaptation on particular genotypes due to the absence of scab control. At least four races of V. inaequalis were found to be established in Latvia, and the resistance genes Rvi1, Rvi3, Rvi4, and Rvi8 have been overcome. On h(9) and h(13), the first symptoms appeared in 2021, indicating the first signs of Rvi9 and Rvi13 gene breakdown.
{"title":"Evaluation of Apple Scab and Occurrence of Venturia Inaequalis Races on Differential Malus Genotypes in Latvia","authors":"O. Sokolova, I. Moročko‐Bičevska","doi":"10.2478/prolas-2022-0075","DOIUrl":"https://doi.org/10.2478/prolas-2022-0075","url":null,"abstract":"Abstract Apple scab caused by the heterothallic ascomycetous fungus Venturia inaequalis is one of the most severe diseases in apple-growing regions worldwide. Annual sexual reproduction of the pathogen ensures the formation of populations with high variability and better adaptability to resistant cultivars. The present study aimed to assess the virulence of the V. inaequalis population in the experimental orchard where introduction, evaluation and breeding of apple cultivars are carried out, and the apple germplasm collection of Latvia is located. Fifteen differential Malus genotypes, obtained within the international Vinquest initiative, were planted in 2016 in the germplasm collection sector of the orchard in five blocks, each containing one tree of each geno-type. In 2017–2021, apple scab symptoms on the leaves were scored according to the methodology used in the Vinquest network. The disease severity increased with each vegetation season, and more genotypes were affected, reaching the maximum in 2021 and clearly indicating the infection source build-up and pathogen’s adaptation on particular genotypes due to the absence of scab control. At least four races of V. inaequalis were found to be established in Latvia, and the resistance genes Rvi1, Rvi3, Rvi4, and Rvi8 have been overcome. On h(9) and h(13), the first symptoms appeared in 2021, indicating the first signs of Rvi9 and Rvi13 gene breakdown.","PeriodicalId":20651,"journal":{"name":"Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77478275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2478/prolas-2022-0071
Ieva Kalniòa, Sarmīte Strautiòa, V. Laugale
Abstract Strawberry growing in high tunnels is widely used in many countries and the area under cover is increasing. Usually, early ripening cultivars are planted in high tunnels to obtain even earlier yield in the season. In this investigation, several new strawberry cultivars and one hybrid (of Dutch breeding) with medium and late ripening time were evaluated for growing in high tunnels in soil. The trial was established in 4 August 2016 in a FVG type tunnel (60 × 4 × 3.35 m). Frigo plants of the following categories of cultivars and hybrids were used in the investigation: ‘Sonata’ (A) and ‘Sonsation’ (A+) of medium ripening time; ‘Faith’ (A+) and hybrid 09-90s-05 (A) of late ripening time; ‘Malwina’ (A+) and ‘Magnus’ (A) of very late ripening time. The plants were grown on raised beds covered with black plastic mulch in double rows with drip irrigation. Soil type was heavy loam. Plant survival after winter, productivity potential, yield, fruit size, the ratio of high quality to damaged fruits in the crop, fruit sensory characteristics, shelf life and biochemical content after freezing were evaluated. According to three-year evaluation results, ‘Sonsation’ had better fruit quality and resistance to crown diseases than ‘Sonata’ and can be considered appropriate for yield forcing in high tunnels. Hybrid 09-90s-05 and ‘Faith’ are not appropriate for growing in high tunnels in heavy soils. Hybrid 09-90s-05 had good yield, but medium fruit quality and low taste score, and it was susceptible to grey mould. ‘Faith’ had low productivity potential and fruits of medium taste. The very late ripening cultivars ‘Malwina’ and ‘Magnus’ had low productivity in all evaluation years, probably because of too heavy soil.
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