Localization and fine mapping of GaMS-1, a male gametophytic mutant of maize

Post-meiotic mutants affecting pollen development are fundamental tools for defining the genetic program controlling microsporogenesis and pollen function. An example of such mutants is gametophytic male sterile-1 (gaMS-1). Heterozygous plants gaMS-1/+ that have a normal phenotype and are female fertile, segregate 1:1 normal:sterile pollen grains and their selfed progeny segregates 1:1 normal:semi-sterile plants. With the final aim of isolating the gene, a positional cloning strategy was adopted. In this paper, we report the results of fine mapping GaMS-1 by different types of molecular markers. Two back crosses were used as mapping populations. They were obtained by crossing the line carrying the mutation with the inbred lines Mo17 and WF9, used as recurrent male parents. Linkage disequilibrium analysis allowed assigning GaMS-1 to the short arm of chromosome 2. By the combined use of SSR, AFLP, PCR markers and ESTs a region of 1 cM containing GaMS-1 was delimited.