Screening of Sunflower BAC Library for the Identification of Specific BAC Clones

To facilitate molecular cytogenetic research and the integration of cytogenetic and genetic linkage groups of sunflower, one BAC and one BIBAC library from HA 89 with BamHI and HindIII, respectively, were developed. The average insert sizes were estimated to be 140 kb and 137 kb in the BamHI and HindIII libraries, respectively. The combined libraries consist of 192,000 clones and represent approximately 8.9 haploid genomes of sunflower. The frequencies of clones that carry chloroplast or mitochondrial DNA were about 2.35% and 0.04%, respectively; and the highly repetitive DNA sequences were roughly 41%. A subset of the library screened by 36 overgo probes, derived from RFLP markers, identified 195 positive clones. These chromosome-specific BAC or BIBAC clones provide crucial tools for association of genetic linkage groups with their corresponding chromosomes using FISH analysis.