IDENTIFICATION OF A CHROMOSOME-SPECIFIC PROBE THAT MAPS WITHIN THE PH1 DELETIONS IN COMMON AND DURUM-WHEAT

The Ph1 (pairing homoeologous) gene is the major factor that determine s the diploid-like chromosome behavior of polyploid wheat. This gene, which is located on the long arm of chromosome 5B (5BL), suppresses ho moeologous pairing at meiosis while allowing exclusive homologous pair ing. In an effort to tag the specific chromosomal region where this ge ne is located, we have previously microdissected chromosome arm 5BL fr om bread wheat and produced a plasmid library by random PCR amplificat ion and cloning. In this work we isolated from this library a 5BL-spec ific probe, WPG90, and mapped it within the interstitial deleted chrom osome fragments carrying Ph1 in common and durum wheat. A PCR assay of Ph1 based on WPG90 was developed that allows an easy identification o f homozygous genotypes deficient for this gene.