A molecular description of mutations affecting the pollen component of the Nicotiana alata S locus

Abstract

Mutations affecting the self-incompatibility response of Nicotiana alata were generated by irradiation. Mutants in the M(I) generation were selected on the basis of pollen tube growth through an otherwise incompatible pistil. Twelve of the 18 Mm plants obtained from the mutagenesis screen were self- compatible. Eleven self-compatible plants had mutations affecting only the pollen function of the S locus (pollen-part mutants). The remaining self- compatible plant had a mutation affecting only the style function of the S locus (style-part mutant). Cytological examination of the pollen-part mutant plants revealed that 8 had an extra chromosome (2n + 1) and 3 did not. The pollen-part mutation in..