dc.description.abstract |
Understanding the extent and partitioning of
diversity within and among crop landraces and their wild/
weedy relatives constitutes the first step in conserving and
unlocking their genetic potential. This study aimed to
characterize the genetic structure and relationships within
and between cultivated and wild sorghum at country scale
in Kenya, and to elucidate some of the underlying evolutionary
mechanisms. We analyzed at total of 439 individuals
comprising 329 cultivated and 110 wild sorghums
using24microsatellitemarkers.Weobservedatotalof295
alleles across all loci and individuals, with 257 different
alleles being detected in the cultivated sorghum gene pool
and 238 alleles in the wild sorghum gene pool. We found
that the wild sorghum gene pool harbored significantly
more genetic diversity than its domesticated counterpart, a
reflection that domestication of sorghum was accompanied
by a genetic bottleneck. Overall, our study found close
genetic proximity between cultivated sorghum and its wild
progenitor, with the extentofcrop-wild divergence varying
among cultivation regions. The observed genetic proximity
may have arisen primarily due to historical and/or contemporary
gene flow between the two congeners, with
differences in farmers’ practices explaining inter-regional
gene flow differences. This suggests that deployment of
transgenic sorghum in Kenya may lead to escape of
transgenes into wild-weedy sorghum relatives. In both
cultivated and wild sorghum, genetic diversity was found
to be structured more along geographical level than agroclimatic
level. This indicated that gene flow and genetic
drift contributed to shaping the contemporary genetic
structure in the two congeners. Spatial autocorrelation
analysis revealed a strong spatial genetic structure in both
cultivated and wild sorghums at the country scale, which
could be explained by medium- to long-distance seed
movement. |
en_US |