TITLE:
Detection of Adaptive Genetic Diversity in Wild Potato Populations and Its Implications in Conservation of Potato Germplasm
AUTHORS:
Alfonso H. del Rio, John B. Bamberg
KEYWORDS:
Adaptive Genetic Diversity, AFLP Markers, Plant Population Structure, Potato Germplasm, Solanum fendleri
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.10,
October
21,
2020
ABSTRACT: A better understanding on how genetic diversity is structured at natural habitats can be
helpful for exploration and acquisition of plant germplasm. Historically,
studies have relied on DNA markers to elucidate potato genetic diversity.
Current advances in genomics are broadening applications allowing the
identification of markers linked to genomic regions under selection. Those
markers, known as adaptive markers, unlock additional ways to value and
organize germplasm diversity. For example, conservation priorities could be
given to germplasm units containing markers associated to unique geographic identity, and/or linked to traits of tolerance
to abiotic stresses. This study
investigated if adaptive marker loci were possible to be identified in a large
AFLP marker dataset of ninety-four populations of the wild potato species S.
fendleri. These populations
originated from six different mountain ranges in southern Arizona, USA. A total
of 2094 polymorphic AFLP markers were used to conduct genetic diversity analyses of populations and mountain ranges.
Adaptive markers were detected using Bayesian methods which distinguished
marker loci departing significantly from frequencies expected under neutral
models of genetic differentiation. This identified 16 AFLP loci that were considered to be adaptive. To contrast diversity parameters generated with each set of markers,
analyses that included all the 2094 AFLP markers, and only the 16
adaptive markers were conducted. The
results showed that both were efficient for
establishing genetic associations among populations and mountain ranges.
However, adaptive markers were better on
revealing geographic patterns and identity which would suggest these markers
were linked to selection at the natural sites. An additional test to determine
if adaptive markers associated to climate
variables found two loci associated to
specific climate variables in populations from different regions but sharing
similar environmental structure. The
distribution of adaptive markers among populations revealed that only two were
needed to build a core subset able to keep all the markers. This preliminary
assessment shows that adaptive genetic diversity could offer an additional way
to measure diversity in potato germplasm and to set up options for conservation
and research.