Mechanized grain harvest of maize becomes increasingly important with growing land plot size in Northeast China.  Grain moisture is an important factor affecting the performance of mechanized grain harvest.  However, it remains unclear what influences grain dehydration rate.  In this study, maize grain dehydrating process was investigated in a two-year field experiment with five hybrids under two planting densities in 2017 and 2018.  It was found that damaged-grain ratio was the main factor affecting mechanized harvest quality, and this ratio was positively correlated with grain moisture content at harvest (R²=0.6372, P<0.01).  To fulfill the national standard of <5% damaged-grain ratio for mechanized grain harvest, the optimal maize grain moisture content was 22.3%.  From silking to physiological maturity, grain dehydrating process was mostly dependent on the thermal time (growing degree days, GDDs) (r=–0.9412, P<0.01).  The average grain moisture content at physiological maturity was 29.4%.  Thereafter, the linear relationship between GDDs and grain moisture still existed, but the correlation coefficient became smaller (r=–0.8267, P<0.01).  At this stage, grain dehydrating process was greatly affected by genotypes.  Grain dehydrated faster when a hybrid has a smaller husk area (r=0.6591, P<0.05), larger ear angle (r=–0.7582, P<0.05), longer ear peduncle (r=–0.9356, P<0.01) and finer ear (r=0.9369, P<0.01).  These parameters can be used for breeders and farmers to select hybrids suitable for mechanized grain harvest.  

Wheat is an important source of essential minerals for human body. Breeding wheat with high grain mineral concentration thus benefits human health. The objective of present study was to identify quantitative trait loci (QTLs) controlling grain mineral concentration and to evaluate the relation between nitrogen (N) and other essential minerals in winter wheat. Wheat grains were harvested from field experiment which conducted in China and analyzed for this purpose. Forty-three QTLs controlling grain mineral concentration and nitrogen-related traits were detected by using a double haploid (DH) population derived from winter wheat varieties Hanxuan 10 and Lumai 14. Chromosomes 4D and 5A might be very important in controlling mineral status in wheat grains. Significant positive correlations were found between grain nitrogen concentration (GNC) and nutrients Fe, Mn, Cu, Mg concentrations (FeGC, MnGC, CuGC, MgGC). Flag leaf N concentration at anthesis (FLNC) significantly and positively correlated with GNC, FeGC, MnGC, and CuGC. The study extended our knowledge on minerals in wheat grains and suggested which interactions between minerals should be considered in future breeding program.

Aerobic rice has the advantage of saving water. Most published work has focused on improving its yield, while few reported on its micronutrient status. In fact, Fe deficiency is a common nutritional problem in the production of aerobic rice. Shortterm hydroponic culture experiments were conducted to study the response of aerobic rice to Fe deficiency and the effect of root exudates from Fe-deficient wheat on its Fe uptake ability. The results indicate that the amount of phytosiderophores (PS) released from aerobic rice did not increase under Fe deficient conditions. The Fe(III) reducing capacity of Fe-deficient aerobic rice did not increase and the solution pH did not decrease significantly. What’s more, no obvious swelling was observed in the root tips. Aerobic rice did not show special responses to improve their Fe nutrition under Fe deficiency as both strategy I and II plants though they were very sensitive to Fe deficiency. This may be a reason which causes Fe deficiency problem in aerobic rice. However, root exudates from Fe-deficient wheat (PSw) could improve its Fe nutrition in the presence of insoluble Fe(OH)3. This suggests that aerobic rice could utilize Fe activated by PSw.