The role of genome size and heterochromatin on maize flowering time

Abstract

Maize exhibits extensive variability in vegetative cycle length (VCL), a trait essential for environmental adaptation. This study investigates relationships among genome size, knob heterochromatin content, and VCL in three inbred lines with contrasting flowering times and their F1 hybrids. The latest-flowering line (Floury-2) exhibited the highest DNA and knob heterochromatin contents, whereas the earliest-flowering line (Gaspé) showed the lowest values. Hybrids displayed intermediate values, consistent with an additive inheritance pattern. Significant positive correlations among DNA content, knob content, and VCL were detected across parental lines and hybrids. Within the limited scope of this study, the results suggest that variation in genome size and knob heterochromatin content may influence cell cycle duration and, consequently, flowering time. By integrating cytogenetic and hybrid analyses, this study reveals a cytogenetic basis for flowering time variation and highlights heterochromatin content as an accessible tool for breeding maize adapted to diverse environments.