Pollinizer Efficacy of Several ‘Ingeborg’ Pear Pollinizers in Hardanger, Norway, Examined Using Microsatellite Markers

Abstract

Abstract. '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 L1

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

“…Higher values obtained for 2018 indicate that a more diverse set of donors contributed with pollen in this growing season and that the pollen contribution was more evenly distributed among various pollinizers. A comparable conclusion has previously been drawn in a similar study on pear cultivar 'Ingeborg' in Norway [28], where higher allele diversity among genotyped seeds was also correlated to pollen contribution by a more diverse set of donors. These changes in pollination patterns between seasons can usually be ascribed to variations in environmental factors, such as rainfall and temperature, which may also negatively affect pollinators [17].…”

“…SSR marker systems can also be used for identifying the male parent (successful pollinizer) in open pollinated fruit in commercial orchards. A recent example is the use of microsatellite markers for identifying pollinizer efficacy, through parentage analyses of pear seeds, on the pear cultivar 'Ingeborg' in Norway [28]. A similar approach was employed by Nishio [29] in order to estimate the effective pollen dispersal distance for cross-pollination in chestnut orchards.…”

Success Rate of Individual Pollinizers for the Pear Cultivars “Ingeborg” and “Celina” in a Nordic Climate

“…The majority of incompatibility signs were observed in the middle part of the transmitting tissue, which was previously proved to be typical for Rosaceae, and was described in some pear cultivars by Shaheen et al [23] and Silva et al [22]. The cultivar "Ingeborg" is triploid and possesses S-alleles S102, S108 and S121 [2]. Since one of the "Ingeborg" parents is the cultivar "Conference", which has the S108 and S121 alleles [48], the crossing combination "Ingeborg" × "Conference" is incompatible, which was also confirmed by our study.…”

“…In the next year, the overlapping period was the longest with "Anna" (7 days) and "Kristina" (7 days). Based on the evidence that "Anna" overlapped and gave the top fruit set in both years, that cultivar can be recommended as a pollinizer for "Ingeborg", as was previously suggested by Gasi et al [2]. Although "Fritjof" had the best parameters in terms of pollen germination in vitro and efficiency of the progamic phase of fertilization in combination with "Ingeborg", it cannot be recommended as a pollinizer for "Ingeborg" due to a short flower overlapping period.…”

“…Pear production has declined in recent decades, mainly due to climatic limitations, a lack of well-adapted cultivars and suitable pollinizers. Unfavorable environmental conditions for pear pollination during the Nordic spring can have a very negative effect on yield quantity in the pear orchards [2,3]. The "Ingeborg" pear ("Conference" × "Bonne Louise") was developed at Balsgård-SLU (Swedish University of Agricultural Sciences) and is currently the most important commercial pear variety grown in Norway in terms of yield tonnage.…”