Identification and mapping of three flower colour loci of potato (S. tuberosum L.) by RFLP analysis.

The inheritance of flower colour in diploid potato (2 n = 2x = 24), was found to be controlled by three unlinked loci D, F and P. To determine the allelism with previously described loci and to dissect this oligogenic trait, a set of tester clones with well-defined genotypes was developed. By backcrossing the mapping population with these tester clones it was possible to obtain monogenic segregation ratios. These were required to detect linkage with RFLP loci and, despite distorted Mendelian ratios, the inheritance and mapping of the D, F and P loci could be unambiguously determined. Locus D, involved in the biosynthesis of red anthocyanins, was mapped on chromosome 2, while locus P, involved in the production of blue anthocyanins, was mapped on chromosome 11. Locus F, involved in the flower-specific expression of gene(s) accommodated by the D and P loci, was mapped on chromosome 10. The tester clones and the map position of the D, F and P loci may be of considerable value in simplifying the genetics of anthocyanin pigmentation.