Phenotypic and Genotypic Characterization of Maize/Teosinte Hybrids After 25-Year and 50-Year Selection Experiments for Perenniality.

Two long-term selection experiments for perenniality were conducted in field plots in Salinas, California. For the 25-year selection experiment, Zea diploperennis was crossed to a stiff-stalk-derived inbred maize line, approximately 1,000 F1 plants were grown in isolation, and perennialism or attributes associated with perennialism were selected for. When the selected perennial phenotype was strong enough, plants were backcrossed to the maize inbred line. Generally, the perennial phenotype was lost after backcrossing but was restored after further generations of selection. For the 50-year selection experiment, Zea perennis was crossed to an unknown line of tetraploid maize, approximately 1,000 F1 plants were grown in isolation, and perennialism was selected for as in the 25-year selection experiment. Multiple generations of selection for perennialism were done before backcrossing to tetraploid Synthetic B maize lines. Similar to the 25-year selection experiment, perennialism was generally lost after backcrossing back could be restored after generations of selection. Both selection experiments produced populations that were ⅞ maize and ⅛ Z. diploperennis or perennis. Eighty seeds from the tetraploid population and 20 seeds from the diploid population were planted in April 2013 in Athens, Georgia for phenotypic and genotypic characterization.