'Svenska' plommon på Balsgård

Om vi säger ’Viktoria’ så tänker du kanske inte bara på en prinsessa utan även på ett mycket omtyckt plommon? Vackert och välsmakande, precis som många andra plommonsorter här i landet. En del av de äldre plommonsorterna återfinns fortfarande i många hemträdgårdar medan de nyare sorterna främst förekommer i yrkesodlingar

Identifying Pollen Donors and Success Rate of Individual Pollinizers in European Plum (Prunus domestica L.) Using Microsatellite Markers

European plum cultivars (Prunus domestica L.) are hexaploid and partially self-fertile or self-sterile requiring compatible pollinizers with overlapping bloom times. Therefore, inter-planting of different pollinizer cultivars is recommended. In order to identify successful pollinizers of the plum cultivars ‘Edda’, ‘Opal’ (self-fertile), ‘Jubileum’, ‘Reeves’, ‘Mallard’, ‘Avalon’, ‘Cacanska Lepotica’ (self-fertile), and ‘Valor’, 60 fruits per cultivar were collected from nine orchards in 2017 and 2018, all of which were located in Ullensvang, western Norway. DNA extraction was subsequently conducted from the obtained embryos, followed by genetic characterization using seven microsatellite markers. Tissue samples from all possible pollinizers were collected during the summer of 2017 and the same DNA approach was conducted. Results showed that ‘Opal’ was the most successful pollinizer among the investigated plum cultivars. The main exception was ‘Cacanska Lepotica’, which consistently displayed very high level of self-pollination. The most successful foreign pollinizer of ‘Opal’ was ‘Mallard’. However, in more than two thirds of embryos extracted from ‘Opal’ fruits self-fertilization was determined. ‘Reeves’ was identified as the most successful pollinizer among embryos collected from ‘Valor’. Among the five cultivars (‘Edda’, ‘Jubileum’, ‘Reeves’, ‘Mallard’, and ‘Avalon’) that did not display self-pollination, the pollinizer success rate of ‘Opal’, ranged from 36.5% (‘Mallard’) to 93.5% (‘Edda’) in 2017, while in 2018 this rate ranged from 43.5% (‘Jubileum’ and ‘Reeves’) up to 96.5% (‘Edda’). Overall, genotyping embryos using SSRs (simple sequence repeats) proved an effective method in determining the success rate of individual pollinizers among European plum cultivars.publishedVersio

Pollinizer efficacy of several ‘Ingeborg’ pear pollinizers in Hardanger, Norway, examined using microsatellite markers

‘Ingeborg’ is currently the main commercial pear cultivar grown in Norway. However, fruit set and subsequent yields of this cultivar have proven to be variable and overall low averaging 10–20 t·ha−1. Pear seeds found in ‘Ingeborg’ fruits are often underdeveloped, suggesting that incomplete fertilization might be a major cause of poor fruit set. In some years, sporadically unfavorable environmental conditions during and immediately after pollination in Hardanger district, western Norway, have resulted in poor fruit set of ‘Ingeborg’. In this study, the pollinizer efficacy of several pollinizers, namely ‘Clara Frijs’, ‘Herzogin Elsa’, ‘Anna’, ‘Colorée de Juillet’, and ‘Belle lucrative’, from several orchards located in the Hardanger district was investigated using 12 microsatellite markers for two growing seasons (2014 and 2016). Pollinizer efficacy was estimated by genotyping ‘Ingeborg’, each individual pollinizer, as well as normally developed seeds from ‘Ingeborg’ fruit, and conducting gene assignment analyses to identify the pollen contribution from each of the pollinizer cultivars. In addition, S-allele genotyping was conducted, and only one pollinizer, ‘Anna’, was identified as being semicompatible with ‘Ingeborg’, whereas all other pollinizers were fully compatible. ‘Clara Frijs’ and ‘Belle lucrative’ were identified as the most efficient pollinizers probably because these cultivars were abundant compared with all other pollinizers within all, but one of the examined orchards. Higher yields could not be attributed to a particular pollinizer, and genetic effects associated with the triploid nature of ‘Ingeborg’ are most likely implicated as a cause behind the low and variable yield of this cultivar.publishedVersio

Pollinizer efficacy of several ‘Ingeborg’ pear pollinizers in Hardanger, Norway, examined using microsatellite markers

‘Ingeborg’ is currently the main commercial pear cultivar grown in Norway. However, fruit set and subsequent yields of this cultivar have proven to be variable and overall low averaging 10–20 t·ha−1. Pear seeds found in ‘Ingeborg’ fruits are often underdeveloped, suggesting that incomplete fertilization might be a major cause of poor fruit set. In some years, sporadically unfavorable environmental conditions during and immediately after pollination in Hardanger district, western Norway, have resulted in poor fruit set of ‘Ingeborg’. In this study, the pollinizer efficacy of several pollinizers, namely ‘Clara Frijs’, ‘Herzogin Elsa’, ‘Anna’, ‘Colorée de Juillet’, and ‘Belle lucrative’, from several orchards located in the Hardanger district was investigated using 12 microsatellite markers for two growing seasons (2014 and 2016). Pollinizer efficacy was estimated by genotyping ‘Ingeborg’, each individual pollinizer, as well as normally developed seeds from ‘Ingeborg’ fruit, and conducting gene assignment analyses to identify the pollen contribution from each of the pollinizer cultivars. In addition, S-allele genotyping was conducted, and only one pollinizer, ‘Anna’, was identified as being semicompatible with ‘Ingeborg’, whereas all other pollinizers were fully compatible. ‘Clara Frijs’ and ‘Belle lucrative’ were identified as the most efficient pollinizers probably because these cultivars were abundant compared with all other pollinizers within all, but one of the examined orchards. Higher yields could not be attributed to a particular pollinizer, and genetic effects associated with the triploid nature of ‘Ingeborg’ are most likely implicated as a cause behind the low and variable yield of this cultivar.publishedVersio

S-Genotyping and Seed Paternity Testing of the Pear Cultivar ‘Celina’

The diploid Celina/QTee® (‘Colorée de Juillet’ × ‘Williams’), one of the most promising pear cultivars developed by the Norwegian breeding program Graminor, was launched in 2010. In Norway, the flowering is medium to late, while the fruits ripen in the beginning of September. The fruits are attractive with an intense red blush (50%) on a green background. Although, ‘Celina’ is cultivated in the most climatically suitable regions for fruit cultivation, present in Norway, unfavorable environmental conditions for pear pollination can have a very negative effect on fruit set and consequent yield. The aim of this study was to determine the S-alleles of ‘Celina’, as well as its frequently used pollinizers, and, through paternity testing of ‘Celina’ seeds, give a recommendation regarding the most important pollinizers of this pear cultivar. In order to accomplish this, ‘Celina’ and its potential pollinizers were all S-genotyped. After harvest, seeds collected from ‘Celina’ fruit in 2017 and 2018 were genotyped using eleven microsatellite markers. Genomic DNA was also extracted from leaf material collected from ‘Celina’, as well as from five pear cultivars used as pollinizers in the three examined orchards, and analyzed using the same marker set. Subsequently a simple sequence repeat (SSR) database was constructed and used for gene assignment analyses with the aim of quantifying pollen donor contribution from individual pollinizers. The obtained results indicate that ‘Anna’, the only examined pollinizer that was fully cross-compatible with ‘Celina’, together with ‘Fritjof’, the genotype which had the highest flowering overlap with ‘Celina’, proved to be the most successful pollinizers across all seasons and orchards. Although both cultivars were ubiquitous in the examined orchards, either as planted trees or as branches introduced during the flowering period, they were the most abundant pollinizers in only one orchard each. It is therefore possible to conclude that pollinizer abundance has a secondary significance in pollinizer success within investigated ‘Celina’ orchards.publishedVersio

Determining Pollinizer Success Rates among Several Apple (<i>Malus domestica</i> L.) Cultivars Using Microsatellite Markers

In order to determine the pollinizer success rates between twelve apple cultivars in 2021 and 2022, 671 apple embryos were collected from 19 different orchards in Ullensvang (southwestern Norway) and Svelvik (southeastern Norway). Genomic DNA was extracted from the collected embryos and, afterward, a genetic characterization with 15 polymorphic microsatellite markers was conducted. An identical set of markers was also used on all twelve mother cultivars, as well as on six crabapple pollinizers, which were found in the investigated orchards. The obtained molecular data enabled paternity analyses to be performed with the objective of assigning a male parent to each embryo. The paternity analyses identified pollen donors for all, except for 3% of the embryos. In most cases, it was possible to identify the most successful pollinizers for each cultivar, with ‘Aroma’ and ‘Discovery’ being the most efficient pollen donors overall. Tree abundance seems to be a major factor in pollinizer success, while semi-cross-compatible characteristics represent a hindrance. Only 7% of the analyzed embryos were determined to have been fertilized by pollinizers outside the orchard, confirming the significance of pollinizer proximity for efficient pollination

Genetic Identity and Diversity of Apple Accessions within a Candidate Collection for the Norwegian National Clonal Germplasm Repository

In order to best conserve, as well as utilize, traditional apple germplasm in Norway, an apple heritage cultivar collection was established in Ullensvang, western Norway, which aims to become the National Clonal Germplasm Repository. The establishment of the apple heritage cultivar collection was preceded by a molecular study that aimed to genotype a large number of apple accessions maintained in various ex situ sites in western and south-eastern Norway, using a rather small set of eight SSR markers. However limited, the marker set managed to identify synonyms, homonyms, and duplicates within and among the investigated collections. In this study, 171 apple accessions from the Ullensvang apple heritage cultivar collection were genotyped using a set of 20 different SSR markers. Approximately half of the accessions have been previously genotyped using eight SSR markers, enabling an assessment of whether the use of a larger marker set would yield a more accurate characterization. Based on the obtained molecular data, the apple heritage cultivar collection was determined to hold a key part of the overall genetic diversity of the Norwegian apple germplasm. Furthermore, the twelve additional SSR markers were able to differentiate several accessions groups originally thought to be synonyms, as well as to provide a more detailed insight into the genetic structure of this germplasm

S-Genotyping and Seed Paternity Testing of the Pear Cultivar ‘Celina’

The diploid Celina/QTee® (‘Colorée de Juillet’ × ‘Williams’), one of the most promising pear cultivars developed by the Norwegian breeding program Graminor, was launched in 2010. In Norway, the flowering is medium to late, while the fruits ripen in the beginning of September. The fruits are attractive with an intense red blush (50%) on a green background. Although, ‘Celina’ is cultivated in the most climatically suitable regions for fruit cultivation, present in Norway, unfavorable environmental conditions for pear pollination can have a very negative effect on fruit set and consequent yield. The aim of this study was to determine the S-alleles of ‘Celina’, as well as its frequently used pollinizers, and, through paternity testing of ‘Celina’ seeds, give a recommendation regarding the most important pollinizers of this pear cultivar. In order to accomplish this, ‘Celina’ and its potential pollinizers were all S-genotyped. After harvest, seeds collected from ‘Celina’ fruit in 2017 and 2018 were genotyped using eleven microsatellite markers. Genomic DNA was also extracted from leaf material collected from ‘Celina’, as well as from five pear cultivars used as pollinizers in the three examined orchards, and analyzed using the same marker set. Subsequently a simple sequence repeat (SSR) database was constructed and used for gene assignment analyses with the aim of quantifying pollen donor contribution from individual pollinizers. The obtained results indicate that ‘Anna’, the only examined pollinizer that was fully cross-compatible with ‘Celina’, together with ‘Fritjof’, the genotype which had the highest flowering overlap with ‘Celina’, proved to be the most successful pollinizers across all seasons and orchards. Although both cultivars were ubiquitous in the examined orchards, either as planted trees or as branches introduced during the flowering period, they were the most abundant pollinizers in only one orchard each. It is therefore possible to conclude that pollinizer abundance has a secondary significance in pollinizer success within investigated ‘Celina’ orchards