Figure 1.—

Generation and selection of tr-Acs. (A) Lines homozygous for an Ac insertion (P1-vv illustrated) were crossed to a Ds tester reporter line containing the r1-sc:m3 allele. Approximately 98% of the progeny kernels inherit the original “donor” Ac, resulting in coarsely spotted kernels. Transpositions inherited with the donor Ac result in an increase in Ac copy number in ∼2% of the progeny and finely spotted or colorless kernels. (B) Typical F₁ ear showing p1 locus variegation (red stripes) and aleurone variegation (purple sectors) mediated by Ac or Ds excision events, respectively. Transmission of two Ac elements through the female gametophyte results in four copies of Ac in the triploid endosperm and a finely spotted or colorless aleurone (white arrow in B).