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Summary of Scientific Objectives: Evidence to date suggests that the
natural subpopulations in
rice (Oryza sativa) and its progenitor, O. rufipogon are indicative
of general combining ability,
similar to the heterotic groups of maize. If true, this hypothesis
has immediate implications for
applied rice improvement and also offers insight into a fundamental
problem in basic biology.
We propose to test the hypothesis that sub-population structure in
rice is predictive of
transgressive variation and to begin to characterize the underlying
genetic basis of this
phenomenon. To do this, we will 1) document the genome-wide
differences in allelic variation
within and between the different subpopulations of O. sativa and O.
rufipogon using a high-
resolution SNP assay, 2) undertake association mapping in rice using
phenotypic evaluations for
26 core agronomic and grain quality traits, 3) systematically
develop genetic materials that will
allow us to explore the relationship between diversity and
transgressive variation that occurs
when subpopulations are crossed and 4) establish a dataset for rice
that allows us to compare our
results with those of the maize diversity project and ultimately with
other cereal species and to
augment the collection of genetic resources for rice available
through the Genetic Stocks-Oryza
(GSOR) located at the Dale Bumpers National Rice Research Center
(DBNRRC).
Broader Impacts: We will work closely with the GRIN and Gramene
databases to ensure public
availability of data and to enhance its comparative potential for the
cereals community. As part
of a targeted educational outreach effort, we will conduct hands-on
genomics exercises in local
high schools, host high school and undergraduate students as summer
interns with an emphasis
on broadening participation of underrepresented groups, and will
develop a multi-media video
presentation exploring the culture of rice in America and in Africa
to be shared with K-8th
graders.
A better understanding of the genetic basis of transgressive
variation in inbred crop
species will have an immediate impact on the global research agenda
for crop improvement.
Presently, there is a great deal of interest in breeding hybrid rice
as a mechanism for delivering
superior varieties to farmers. But without a sound scientific
understanding of the genetic
mechanisms that underlie superior performance in naturally inbreeding
species, we may overlook
some of the most promising opportunities to capture superior
performance in the world\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s inbred
crop varieties. The knowledge we gain from this project will help
inform our thinking about how
to best characterize and manage Oryza gene pools and about the
relative investments that we, as
a society, choose to make in developing inbred and/or hybrid
varieties of our most important
food staples. |
Research