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 func tion. An example of such mutants is gametophytic male sterile-1 (gaMS-1). H eterozygous plants gaMS-1/+ that have a normal phenotype and are female fer tile, segregate 1:1 normal:sterile pollen grains and their selfed progeny s egregates 1:1 normal: semi-sterile plants. With the final aim of isolating the gene, a positional cloning strategy was adopted. In this paper, we repo rt the results of fine mapping GaMS-1 by different types of molecular marke rs. Two back crosses were used as mapping populations. They were obtained b y crossing the line carrying the mutation with the inbred lines Mo17 and WF 9, used as recurrent male parents. Linkage disequilibrium analysis allowed assigning GaMS-1 to the short arm of chromosome 2. By the combined use of S SR, AFLP, PCR markers and ESTs a region of 1 cM containing GaMS-1 was delim ited.