A semi in vivo pollination technique to assess the level of gametophytic self-incompatibility and pollen tube growth in pear (Pyrus communis L.).

Abstract

Key message We describe a semi in vivo pollination technique to determine the compatibility relation between different pear cultivars. This assay provides a valuable addition to existing tools in GSI research. The gametophytic self-incompatibility (GSI) system in Pyrus inhibits fertilization by pollen that shares one of the two S-alleles of the style. Depending on their S-locus genotype, two pear cultivars therefore either show a cross-compatible, semi-compatible or incompatible interaction. Because GSI greatly influences seed and fruit set, accurate knowledge of the compatibility type of a cultivar is key for both pear fruit production and breeding. Currently, compatibility relations between different pear cultivars are generally assessed via S-genotyping. However, this approach is restricted to the currently known S-alleles in pear, and does not provide functional assessment of the level of (self-)incompatibility. We here present an optimized semi in vivo pollination assay, that enables quantitative analysis of (self-)incompatibility in pear, and that can also serve useful for more fundamental studies on pollen tube development and pollen-style interactions. This assay involves in vitro incubation of cut pollinated styles followed by microscopic counting of emerging pollen tubes at a specific time interval. The validity and selectivity of this method to determine compatibility interactions in pear is demonstrated in the cultivars "Celina" and "Packham's Triumph." Overall, this technique constitutes a valuable tool for quantitatively determining in vivo pollen tube growth and (cross-)compatibility in pear.

Plant phenotyping relevance

ナシの受粉後の花粉管成長と交雑適合性を定量化する半生体測定法を開発・最適化し、品種で妥当性を実証しているため、植物表現型取得法が中心である。

Code and data availability

The paper states its phenotypic data (pollen tube counts, germination percentages) is in Supplementary Table S3, but no public URL or repository is given for it; code availability is 'Not applicable'. No paper-specific public asset with an actionable authors' URL exists among the supplied blocks.

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