Identification of Self-Incompatibility Alleles by Specific PCR Analysis and S-RNase Sequencing in Apricot

Abstract

Self-incompatibility (SI) is one of the most efficient mechanisms to promote out-crossing in plants. However, SI could be a problem for fruit production. An example is apricot (Prunus armeniaca), in which, as in other species of the Rosaceae, SI is determined by an S-RNase-based-Gametophytic Self-Incompatibility (GSI) system. Incompatibility relationships between cultivars can be established by an S-allele genotyping PCR strategy. Until recently, most of the traditional European apricot cultivars were self-compatible but several breeding programs have introduced an increasing number of new cultivars whose pollination requirements are unknown. To fill this gap, we have identified the S-allele of 44 apricot genotypes, of which 43 are reported here for the first time. The identification of Sc in 15 genotypes suggests that those cultivars are self-compatible. In five genotypes, self-(in)compatibility was established by the observation of pollen tube growth in self-pollinated flowers, since PCR analysis could not allowed distinguishing between the Sc and S8 alleles. Self-incompatible genotypes were assigned to their corresponding self-incompatibility groups. The knowledge of incompatibility relationships between apricot cultivars can be a highly valuable tool for the development of future breeding programs by selecting the appropriate parents and for efficient orchard design by planting self-compatible and inter-compatible cultivars.

Identification of S-Allele Based Self-incompatibility of Turkish Pear Gene Resources

“…According to 46 self-compatible genotypes, considering the proportion of regional samples, the highest proportion (40%) with 13 genotype out of 32 was assigned to the Marmara region and the lowest percentage with 3 genotypes out of 24 (12% of the region samples) allocated to the Central Anatolian region so, more attention should be paid to contrivances, regarding commercial production and orchard design in this region. The results confirmed that the self-incompatibility feature tends to increase in the species, which is contrary to the former reports that most cultivars were compatible (Mehlenbacher et al 1991;Herrera et al 2018).…”

“…It should be noted that standardization of the S-alleles identification criteria is essential in various laboratories, including the full sequencing of S alleles and utilization of the identic primer pairs. This will lead to easy S-allele identification without confusion and will provide valuable information for pear breeders (Herrera et al 2018). Obtained results in this study make it possible to organize the incompatibility relationships between pear genotypes with former unknown pollination knowledge and provide the possibility to select suitable parents in designing new crosses in pear production and breeding programs.…”

Finding a Compatible Partner: Self-Incompatibility in European Pear (Pyrus communis); Molecular Control, Genetic Determination, and Impact on Fertilization and Fruit Set

“…The DNA sequence encoding this hexapeptide has frequently been used for the development of consensus primers for PCR-based S-genotyping (DeFranceschi et al., 2012). S-RNase genotyping by PCR is commonly used in Rosaceae species to determine incompatibility relations between cultivars, often in combination with field-controlled pollination assays (Zuccherelli et al., 2002; Larsen et al., 2016; Herrera et al., 2018). Figure 3 displays a schematic representation of the protein sequence of the S-RNase of Pyrus, Prunus , and Solanaceae.…”

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

“…In these crosses, pollen tube growth stops somewhere along the style length and practically no pollen tubes can be observed at the base [22,23]. Self-incompatibility is one of the most efficient mechanisms to promote out-crossing in plants but could be a problem for fruit production [24]. So far, 19 S-RNase alleles have been cloned and sequenced for European pear, which can be used to characterize more than 130 cultivars [25].…”