Optimizing male inbred sowing for hybrid maize seed production in winter and spring

Determining the optimal planting time for male inbred lines is essential to maximize seed yield in maize hybrids. A two-year field experiment (2021–2023) was conducted in Rampur's Agronomy Farm (Agriculture and Forestry University) in the central Terai region to assess the effect of staggered male inbred lines on floral synchronization, hybrid maize seed yield, and quality in winter and spring using a split-plot design with four replications. The main plot included inbred lines of Rampur Hybrid-10 (RH-10) and Rampur Hybrid-16 (RH-16), while sub-plots tested four staggered male inbred sowing dates: two days before to four days after female sowing at two-day intervals in spring, and same day to six days after in winter. In winter, same-day sowing of male and female inbreds resulted in short tasseling-silking intervals (TSI). In spring, RH-10 achieved synchronization with male lines sown two days earlier, while RH-16 showed perfect synchronization with same-day sowing. Staggered male line sowing significantly influenced yield attributes and seed yield, with seed yield declining by 29 to 57% as TSI increased. RH-16 achieved higher yields, but the varieties' effect on seed qualities was insignificant. In spring, sowing male lines two days earlier or simultaneously resulted in significantly higher yield attributes, yield, and germination percentage of stored seeds. In winter, same-day sowing resulted in higher seed yields and improved germination of seeds stored for 150 days. Sowing male lines two days earlier or simultaneously in spring, and on the same day in winter, reduced the TSI, enhancing synchronization, seed yield, and quality in hybrid maize seed production in Nepal's Terai regions. • In winter, same-day sowing of male and female inbred lines shortened tasseling-silking intervals • Different hybrids required staggered sowing of male lines for synchronization in the spring season. • Seed yield was unaffected by season but significantly influenced by tasseling-silking intervals. • In spring, same-day or earlier male sowing increased germination rates. • In winter, same-day sowing enhanced seed yield and germination of stored seeds.