PAG-I Plant Genome I Conference

Town & Country Conference Center, San Diego, CA, November, 1992.


PG-I: 76pg1

RFLP MAP CONSTRUCTION IN SORGHUM AND COMPARATIVE MAPPING IN MAIZE.

M. G. Pereira 1, M. Lee 1, P. Bramel-Cox 2, and W. L. Woodman 1. l Department of Agronomy, Iowa State University, Ames, IA 50011,and 2 Department of Agronomy, Kansas State University, Manhattan, KS 66502.


The first RFLP linkage map in Sorghum based on CDNA probes has been developed. Probes were mapped in an F2 population represented by 78 individuals of the cross, CK60 x P1229828. Probes were derived from libraries of maize cDNAs (160) and sorghum genomic PstI fragments (19), and collections of mapped maize genomic clones (42) selected for their ability to produce single-low copy, polymorphic hybridization patterns with sorghum. The cDNA probes provided much stronger signal intensity and detected higher frequencies of polymorphism with HindIII and EcoRI than the maize genomic probes. The probes defined 203 loci placed into 10 linkage groups, 1756 cM. Eighty percent of the markers linked in maize were also linked in sorghum. Parents used to create the mapping populations are extremely divergent for vegetative and reproductive morphology, resistance to greenbug (Schizapus graminum) and sorghum downy mildew (Peronosclerospora sorghi), and maturity. Studies to locate genes controlling these traits in sorghum, compare their map positions in maize, and to asses conservation of gene order between sorghum and maize have been initiated.


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