Genetic and fitness measurements of Brighamia accessions for APPS

Premise of the study: Living collections maintained for generations are at
risk of diversity loss, inbreeding, and adaptation to cultivation. To
address these concerns the zoo community uses pedigrees to track
individuals and implement crosses that maximize founder contributions and
minimize inbreeding. Using a pedigree management approach in an
exceptional plant, we demonstrate how conducting such strategic crosses
can minimize genetic issues that have arisen under current practices.
Methods: We performed crosses between these collections and compared the
fitness of progeny, including plant performance and reproductive health.
We genotyped the progeny and paternal accessions to measure changes in
diversity and relatedness within and between accessions. Results: The mean
relatedness among individuals of an accession, suggests they are full
siblings. As a result there was high inbreeding and low diversity within
an accession, although less so among accessions. Progeny from the wider
crosses had increased genetic diversity, while selfed accessions were
smaller and less fertile. Discussion: Institutions which hold exceptional
species should consider how diversity is maintained within their
collections. Implementing a pedigree-based approach to managing
reproduction of ex situ plants will slow the inevitable loss of genetic
diversity and in turn, result in healthier collections.