Pollen gene flow and molecular identification of full-sib families in small and isolated population fragments of Gleditsia triacanthos L

© 2016, Canadian Science Publishing. All rights reserved. To analyze the utility of isolated remnant populations for full-sibling (full-sib) identification among openpollinated single-tree progeny in the outcrossing and insect-pollinated tree Gleditsia triacanthos L. (honey locust), we performed paternity analyses in forest fragments from two geographic regions using nuclear microsatellites. The first plot (Butternut Valley population) comprised only 7 trees, and 552 seedlings from a single seed parent were characterized at nuclear microsatellites. A large number of putative pollen donors (59) were identified in kinship analyses, but their individual contributions to the progeny were highly variable. Kinship and paternity analyses identified 149 putative full-sibs for genetic mapping sired by an external (unsampled) pollen parent. To better assess the frequency of long-distance pollen dispersal, a total of 180 seeds were collected from 6 seed parents in another fragmented population. In both plots, contemporary pollen dispersal occurred generally from outside the plots (99.38% and 87.50%–100% at the Butternut Valley and Ames Plantation sites, respectively) and thus over very long distances (\u3e 12 000min the Ames Plantation) suggesting that in highly fragmented landscapes, insect pollinators of honey locust are likely very effective long-distance dispersers