Tester stocks carrying confirmed mutations at the gl1, gl2, gl3, gl4, gl6, gl8, gl14, gl15, gl17, gl18, and gl19 loci and the two duplicate gene pairs gl5 & gl20 and gl21 & gl22 have been recovered. Each of these gl mutants or mutant pairs is being backcrossed into the inbred B73. Efforts are continuing to recover the remaining stock, gl9. All tested inbred lines are homozygous for Gl5, Gl20, Gl22, Gl22. Successful allelism tests have been conducted on 11 of Neuffer's 27 EMS-induced gl mutations. Extensive transposon tagging experiments have resulted in the recovery of Mutator-induced alleles of gl1, gl2, gl3, gl4, gl6, gl8, gl11, gl19 and two newly defined loci, gl25 and gl26. Scanning electron microscopy analysis of a chimeric seedling has established that gl3 is expressed in a cell autonomous fashion. The gl1, gl2, gl6 and gl8 loci have been mapped relative to RFLP markers.