LAUSR

BACKGROUND Harvest at the proper time is a key factor contributing production of high-quality seeds. We conducted field experiments to harvest seeds at 11 developmental stages for three years, for investigation of seed vigor traits in three early-maturity maize varieties and two late-maturity varieties in one location for three years. RESULTS Significant correlations (r = 0.72 ~ 0.89) were found among six seed related traits of standard germination (SG), accelerated aging germination (AAG), cold test germination (CTG), hundred-seed weight (HSW), seed moisture content (SMC), and ≥ 10°C accumulated temperature from pollination to harvest (AT10). Analysis of Variance showed that harvest stage, year and variety had significant effects on all traits, and harvest stage took the greatest effect. The responses of SG, AAG, CTG, HSW and SMC to harvest stage fitted to quadratic models, while AT10 fitted to linear model. From the quadratic models, an ideal harvest time (IHT, the final date to reach maximum SG, AAG and CTG) could be calculated for each variety. The three early-maturity varieties reached their IHT at 54.94-58.44 days after pollination (DAP); while the two later-maturity varieties reached at several days later (at 59.87-59.90 DAP). Consistently, the early-maturity varieties required less AT10 to reach the IHT than the later-maturities. However, all varieties reached the IHT at similar SMC levels of about 35%. CONCLUSION The later-maturity varieties reached the IHT at later DAPs when they acquired more AT10 than the early-maturities, but both reached at similar SMC. This article is protected by copyright. All rights reserved.