Sowing Date Regulates the Growth and Yield of Broomcorn Millet (Panicum miliaceum L.): From Two Different Ecological Sites on the Loess Plateau of China

A two-year experiment was conducted to determine the optimal combinations of sowing date and variety maturity using four broomcorn millet (Panicum miliaceum L.) varieties. The results showed that dates had significant effects on leaf net photosynthesis (Pn) chlorophyll fluorescence multivariate analysis variety, date, measuring stage their interactions were in both sites. days from seeding strongly decreased (6–35 d) ratios reproductive growth vegetative increased V2 V4 V1 V3 Baoji all varieties Yulin. highest yield Jinshu 5 Shaanmei 1 Yulin, total average Yulin (2408.3 kg ha−1) higher than (1385.2 reduced by 12.4% 27.2% compared BJ1 15.5%, 3.6% 12.7% YL1 Correlation key meteorological factors which limit different for two Moreover, linear fitting indicated accumulated temperature number (R2 = 0.5306 0.5139) during whole period 0.4323) top three affecting precipitation 0.386) affected Overall, this study determined with a short should have delayed sowing, while those longer are suitable early semi-arid area.