The Effective Pollination Period of European Plum (Prunus domestica L.) Cultivars in Western Norway

Abstract

This study evaluated the effective pollination period (EPP) in four European plum (Prunus domestica L.) cultivars (‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’) during two years (2018–2019) under the environmental conditions in western Norway. The pollination of plum cultivars was carried out one, three, five, seven, and nine days after anthesis (DAA) with a pollen mix of two compatible cultivars (‘Victoria’ and ‘Opal’). Initial, middle-season, and final fruit set was recorded after one month and two months after pollination and just before the harvest, respectively. On average from both years cultivar ‘Jubileum’ had the highest fruit set when pollinated one, three, five, seven, and nine DAA (33.23%, 30.83%, 8.47%, 3.08%, and 1.15%, respectively), which was more than two folds higher fruit set than in the other studied cultivars. Cultivar ‘Jubileum’ showed significantly reduced fruit set between pollination on five and nine DAA, while cultivars ‘Mallard’, ‘Edda’, and ‘Reeves’ had markedly reduced fruit set if pollinated three to five DAA, implying that the EPP in ‘Jubileum’ was five days while in the rest it was three days. Variation of weather conditions during the flowering period in both years did not have a major effect on the receptivity of stigmas in the studied plum cultivars, which means that the existing differences in the length of EPP is maternal-genotype dependent.

Viability of Embryo Sacs and Fruit Set in Different Plum (Prunus domestica L.) Cultivars Grown under Norwegian Climatic Conditions

“…In this study, higher values of fruit set were obtained in both years, as a consequence of artificial pollination. However, according to Fotirić Akšić et al [28], regardless of the differences in climatic conditions in those two seasons, EPP was 3 days for 'Mallard', 'Edda', and 'Reeves' in both years, and 5 days for 'Jubileum' in both years. In our study, under open pollination, the values of fertilized embryo sacs and fruit set in the studied plum cultivars showed temperature dependence-especially in the post-full-flowering period.…”

“…Previously, the progamic phase of fertilization and fruit set in the cultivars 'Mallard', 'Edda', 'Jubileum', and 'Reeves' was observed, in an attempt to determine the best pollinizers for those cultivars [14]. Furthermore, in these plum cultivars, pollen donors and success rates of individual pollinizers using microsatellite markers have been identified [1], together with the determination of the effective pollination period under the specific Nordic climate [28].…”

Profiling of Metabolites in Organically Grown Plums from Norway: Does Location or Cultivar Matter?

“…According to the literature data, plum cultivation in Norway has a long tradition, dating back to the Middle Ages [30]. Plum production is organized around lakes in the eastern part of the country and around fjords in the western part (between 58 • N and 62 • N), which overall represents the northern limit of commercial fruit production in the world [31]. Although the northern latitudes are under the influence of the Gulf Stream, the growing seasons is short and relatively cool [32].…”

Genetic Characterization of the Norwegian Apple Collection

“…The Fjord districts in South West Norway and around the lakes in the eastern part of the country, at around latitude 60 • north, are where commercial fruit production is located. This is the world's most northern border for commercial apple production [5]. The climatic conditions where the apples are grown depend on the Gulf Stream, which flows from south to northeast along the Norwegian coast.…”

“…Today, releasing new apple cultivars with superior fruit quality characteristics, adapted to a changing climate, is important to most breeding programs [2,5]. Several factors have dramatically reduced the genetic diversity of apples, such as the use of few and related cultivars together with vegetative practices (cuttings and grafting) [7].…”