XVI International Botanical Congess
We have introgressed a mutant (stay-green") allele of a gene associated with leaf senescence from the grass Festuca pratensis into related Lolium species. The location of the alien gene in recombinant chromosomes has been established by in situ hybridisation. Isogenic" lines of Lolium temulentum with and without a single small Festuca chromosome segment have been developed, and senescence compared in homozygous stay-green and homozygous wild-type plants. We isolated cDNAs for transcripts differentially expressed in mutant versus wild-type plants. The mutant version of one such cDNA carries 3 separate polymorphisms corresponding to identical sequence variations in F. pratensis. This locus is clearly associated with the alien stay-green" segment. We believe that the introgression approach has wide applicability for gene mapping and isolation..