Une ébauche de carte cytologique pour le chromosome VII de Petunia hybrida hort.

Gamma-ray treatment and telotrisomic analysis were used for cytological mapping in petunia, which resulted in the genetic marking of both arms of the shorter median chromosome of the genome. An4, which is responsible for anthocyanin synthesis in part of the corolla and in the pollen, is located rather distally on the arm called α; both vs5, a mutation for virescent rosettes, and ph3, producing bluish hues of flower anthocyanins, are located on the other arm. The possibility of determining the order and physical distance of the genes with regard to the centromere is discussed. The sketch of a cytological map for chromosome VII revealed, as previously for chromosome VI, a strong inhibition of crossing-over between two genes located on both arms of the chromosome.Key words: petunia, telotrisomy, gene location, deletion.[Traduit par la revue]

Genetic and cytological maps in petunia: a sketch for chromosome VI

Through mutagenesis, deficiencies, and deficient trisomics it was possible to determine the cytological location of four closely linked genes of chromosome VI in petunia (An2, Rt, Dg1, and An1). An2 lies at the distal end of the short arm, whereas Rt, Dg1, and An1 are located on the long arm. In addition, mutagenesis experiments revealed a high sensitivity to radiation or tolerance for deficiency of the short arm, in contrast with the apparent stability of the long arm. Key works: petunia, trisomy, telotrisomy, gene location, genetic mapping, cytological mapping, mutagenesis, deletion.