Genotypic and phenotypic changes in wild barley (Hordeum vulgare subsp. spontaneum) during a period of climate change in Jordan

Climate change and other anthropogenic
disturbances can lead to the loss of genetic variation
and thereby affect evolutionary potential and survival
of plant populations in the wild. We examined these
predictions in the primary wild relative of barley,
Hordeum vulgare L. subsp. spontaneum (K. Koch)
Thell., within its center of diversity, in Jordan.
Changes in genotypic and phenotypic diversity were
assessed using seed samples collected in 1981 and
2012 from the same 18 sites across Jordan. The overall
population structure was conserved, but we observed
an increase of within population genetic diversity and
a reduction in population differentiation. Phenotypic
variation differed among years and sites but the
magnitude and direction of change variated among
sites. While the sampled region became significantly
hotter and drier during this period, simple correlation
models did not support association between measures
of climate change and the observed genetic and
phenotypic changes. Agricultural activities that promote
disturbance and demographic fluctuations may
affect crop wild relatives that grow in agricultural
landscapes, in unexpected ways. The observed
increase in genetic diversity within populations might
be explained by increased migration or by an advantage
of increased genetic variation in the face of
variable environmental conditions. This study provides
a new perspective on the range of possible
responses of crop wild relatives to environmental
pressures.