Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 77pg1
IDENTIFICATION AND RAPD MAPPING OF QUANTITATIVE TRAIT LOCI
ASSOCIATED WITH DROUGHT TOLERANCE IN SORGHUM.
Mitch Tuinstra 1, Peter Goldsbrough 1, Ed Grote 2 and Gebisa
Ejeta 2, Departments of Horticulture 1 and Agronomy 2, Purdue
University, West Lafayette, IN 47907.
Drought is the major cause of crop yield reduction in the
world today. Genetic improvement for drought tolerance is the
long term solution to this problem. Progress toward this goal
using traditional breeding techniques has been slow because of
the complexity of character expression and its quantitative
inheritance. We are using random amplified DNA markers (RAPDs)
to identify quantitative trait loci (QTLs) associated with
drought tolerance within a family of recombinant inbred (RI)
sorghum lines. A set of 100 RI lines was developed from two
divergent inbreds (TX7078 and B35) which differ in drought
response. The RI lines have been characterized and shown
significant variation for several drought and agronomic
characteristics. To date, the RI family has been genotyped for
38 polymorphic RAPD markers. Preliminary correlation matrix
analysis has identified a number of potential linkage groups. An
extensive map will be produced by the addition of more markers.
When the lines have been adequately genotyped, analytical
programs such as MapMaker-QTL and SAS will be used to detect
linkage between marker loci and loci that affect drought
tolerance in sorghum. Identification of markers which are
associated with drought tolerance may facilitate future breeding
efforts aimed at improving this trait through marker assisted
selection (MAS).
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