THE MAPPING OF PHYTOCHROME GENES AND PHOTOMORPHOGENIC MUTANTS OF TOMATO

The map positions of five previously described phytochrome genes have been determined in tomato (Lycopersicon esculentum Mill.) The position of the yg-2 gene on chromosome 12 has been confirmed and the classica l map revised. The position of the phytochrome A (phyA)-deficient fri mutants has been refined by revising the classical map of chromosome 1 0. The position of the PhyA gene is indistinguishable from that of the fri locus. The putative phyB1-deficient tri mutants were mapped by cl assical and RFLP analysis to chromosome 1. The PhyB1 gene, as predicte d, was located at the same position. Several mutants with the high pig ment (hp) phenotype, which exaggerates phytochrome responses, have bee n reported. Allelism tests confirmed that the hp-2 mutant is not allel ic to other previously described hp (proposed here to be called hp-1) mutants and a second stronger hp-2 allele (hp-2(j)) was identified. Th e hp-2 gene was mapped to the classical, as well as the RFLP, map of c hromosome 1.