Combining rare alleles and grouped pollen donors to assign paternity in pollen dispersal studies

Abstract

Premise Pollen dispersal plays a critical role in gene flow of seed plants. Most often, pollen dispersal is measured using paternity assignment. However, this approach can be time‐consuming because it typically entails genotyping all pollen donors, receptors, and offspring at several molecular markers. Methods We developed a faster, simpler protocol to track paternity, using pollen receptors and grouped pollen donors that possess rare alleles. We tested this approach using wind‐pollinated Amaranthus tuberculatus and insect‐pollinated Solanum lycopersicum. After screening potential markers for rare alleles, we grew both species in experimental arrays under field conditions. Results All tested A. tuberculatus seeds and 97% of S. lycopersicum fruits could be assigned to the grouped pollen donors using each of two markers. From these results, we could infer paternity of untested offspring and assess pollen dispersal patterns in each array. Discussion By combining rare alleles and grouped pollen donors, we could assess pollen dispersal for both species and across all arrays after genotyping a small number of pollen donors and a representative subset of offspring. While directly applicable to A. tuberculatus and S. lycopersicum, this approach could be used in other species to assess pollen dispersal under field conditions.

Pollen dispersal patterns differ among sites for a wind‐pollinated species and an insect‐pollinated species

“…Seeds were germinated and seedlings were grown in a greenhouse at the Louis Calder Center (Fordham University) field station in Armonk, New York, USA during the spring of 2015 ((Solanum lycopersicum -April/May; Amaranthus tuberculatus -May/June), following Butcher et al (2020b). Briefly, seeds were germinated in 53 × 28 × 5 cm (l × w × d) potting trays (Griffin Greenhouse Supplies, Tewksbury, Massachusetts, USA) containing Sungro Sunshine Soilmix 4 (Sungro Horticulture, Agawam, Massachusetts, USA) supplemented with Osmocote 14-14-14 fertilizer (Scotts Miracle-Gro, Marysville, Ohio, USA).…”

“…Molecular techniques used for paternity assignment followed Butcher et al (2020b), except that Amaranthus tuberculatus hypocotyl and cotyledon tissue was incubated with AP1 buffer and RNase A (Qiagen, Hilden, Germany) for 2 hr after disruption. In brief, we extracted DNA from maternal and paternal leaf tissue, as well as from seeds produced during the experiment.…”

“…This typically requires a multi-marker approach of genotyping all potential pollen donors and offspring to assign paternity to a single pollen donor (i.e., paternity analysis) (Van Rossum et al, 2011). Alternatively, a rare allele approach coupled with grouped pollen donors can be used to determine paternity and measure effective pollen dispersal after genotyping a limited number of pollen donors and a representative number of offspring (Butcher et al, 2020b).…”

Long-Distance Pollen Dispersal in Urban Green Roof and Ground-Level Habitats

“…Paternity was assigned using the rare allele approach, as described in Butcher et al (2020b). In brief, all A. tuberculatus pollen receptor and donor plants, and a subset of seeds, were genotyped at markers for the external transcribed spacer region (ETS) and putative DEAD box ATP-dependent RNA helicase gene (PutDead).…”