Baili Feng

The field experiments were conducted to explore the changes in metabolism related to leaf senescence in proso millet (Panicum miliaceum L.) under proso millet/mung bean intercropping system. Results showed that intercropping increased leaf pho...

Field experiments involving proso millet (Panicum miliaceum L.) cultivar under four nitrogen (N) levels (N0, N60, N105 and N150) were conducted in 2015 and 2016 to explore the decrease in grain yield under N deficiency related to the changes in leaf photosynthetic characteristics, carbon (C)–N balance and N use efficiency. Results showed that N deficiency decreased the net photosynthesis rate, stomatal conductance, transpiration rate and chlorophyll content and increased the intercellular CO₂ concentration of proso millet flag leaves from flowering to maturity. N deficiency negatively regulated the C–N balance and increased the C/N ratio by reducing the total N, soluble protein and soluble sugar contents, resulting in a high starch content. N uptake and utilisation were significantly reduced because of less available N. Significantly positive correlations were observed between the grain yield and photosynthetic characteristics or N use efficiency, whereas a negative correlation was found between the grain yield and the C/N ratio. The yields generated by N0, N60 and N105 were lower than that of N150 in both years. The N fertiliser regression formulae developed in the study would provide useful information about the N fertiliser rate of proso millet.

Starches of four varieties of waxy proso millet were examined in terms of granule morphology, amylose, transparency, retrogradation, pasting, and thermal properties. The starches had great numbers of large polygonal granules with smooth edges, small numbers of small spherical granules, and an average granule size of 6.12 µm. Compared with the starches of non‐waxy proso millet and maize, the starches of the waxy proso millet varieties had lower amylose contents (0.21%) and higher phosphorus contents (1.85 mg/100 g); higher transparency (29.84%) and lower volume percentages of retrogradation (5.01%); higher peak viscosities (3304 cP), trough viscosities (2422 cP) and breakdowns (882 cP), and lower setbacks (267 cP); and lower onset temperatures (To) (69.7°C), peak temperatures (Tp) (75.3°C), final temperatures (Tc) (80.8°C) and enthalpies (ΔH) (10.55 J/g) in their starch gelatinization.