Phenotypic and genotypic characterization of an amylose-free starch mutant of the potato

The amylose-free (amf) potato mutant 86.040 has been characterized phenotypically and genotypically . Not only storage starch in tubers and metabolic starch in leaves but also starch in cells with specific functions, suchas columella cells in the root cap and guard cells of stomata, was amylose-free . Doubled amf-clones of 86 .040 flowered well, but the percentage of stainable pollen was low (8.2%). Therefore, they were used as female parent in crosses with diploid amylose-containing plants . Over 1400 pollinations gave 13 berries, all dropping off prematurely ; they contained 78 ovules with embryos at different developmental stages . Twenty Ft plants were obtained by embryo rescue, all having amylose starch . Three of them were characterized more extensively . They flowered well, and pollen stainabilitity as well as seed set were high. Analysis of the F, plants and of F, X F, progeny plants showed that the amf-character is monogenic and recessive . The locus involved was designated amf+ and the mutated allele amf