Propylea japonica (Coleoptera: Coccinellidae) is a natural enemy insect with a wide range of predation in Chinese mainland and is commonly used in pest management.  However, its genetic pattern (i.e., genetic variation, genetic structure, and historical population dynamics) is still unclear, impeding the development of biological control of insect pests.  Population genetic research has the potential to optimize strategies at different stages of the biological control processes.  This study used 23 nuclear microsatellite sites and mitochondrial COI genes to investigate the population genetics of Propylea japonica based on 462 specimens collected from 30 sampling sites in China.  The microsatellite dataset showed a moderate level of genetic diversity, but the mitochondrial genes showed a high level of genetic diversity.  Populations from the Yellow River basin were more genetically diverse than those in the Yangtze River basin.  Propylea japonica has not yet formed a significant genealogical structure in China, but there was a population structure signal to some extent, which may be caused by frequent gene flow between populations.  The species has experienced population expansion after a bottleneck, potentially thanks to the tri-trophic plant–insect–natural enemy relationship.  Knowledge of population genetics is of importance in using predators to control pests.  Our study complements existing knowledge of an important natural predator in agroecosystems through estimating its genetic diversity and population differentiation and speculating about historical dynamics.

Rice grain yield and quality declines are due to unsuitable temperatures from wide regions and various sowing dates.  This study aimed to evaluate the effects of temperature on rice yield and quality at different phenological periods and obtain suitable temperatures for phenological periods in the Yangtze River Basin, China.  This study conducted experiments on different sowing dates under different areas in the Yangtze River Basin to observe and compare the differences in rice growth, yield, and quality, controlling for regional varieties.  The results showed significant differences in rice growth, yield, and quality among sowing dates and areas, which were related to the average daily temperature during the vegetative period (VT) and the first 20 days of the grain-filling period (GT20).  In addition, there was a smaller variation in the average daily temperature in the reproductive period (RT) than in the two phenological periods.  Therefore, according to the VT and GT20 thresholds of different yields and qualities, the experimental results were divided into four scenarios (I, II, III, and IV) in this study.  In Scenario I, high head rice production (rice grain yield multiplied by head rice rate) and rice quality could be obtained.  The head rice production of Scenarios III and IV was lower than that of Scenario I, by 30.1 and 27.6%, respectively.  In Scenario II, the head rice production increased insignificantly while the chalky grain rate and chalkiness were 50.6 and 56.3% higher than those of Scenario I.  In conclusion, the Scenario I combination with VT ranges of 22.8–23.9°C and GT20 ranges of 24.2–27.0°C or the combination with VT ranges of 23.9–25.3°C and GT20 ranges of 24.2–24.9°C, which can be obtained by adjusting sowing date and selecting rice varieties with suitable growth periods, is recommended to achieve high levels of rice grain yield and quality in the Yangtze River Basin. 

Soybean is a widely planted genetically modified crop around the world. However, it is still one of the most recalcitrant crops for genetic transformation due to the difficulty of regeneration via organogenesis and some factors that affect the transformation efficiency. The percentages of resistant bud formation and transient expression efficiency are important indexes reflecting the regeneration and transformation efficiency of soybean. In this study, the percentages of resistant bud formation and transient expression of β-glucuronidase (GUS) were compared after treatment with sonication or surfactant and co-treatment with both. The results showed that treatment with either sonication or surfactant increased the percentage of resistant bud formation and transient expression efficiency. The highest percentages were acquired and significantly improved when cotyledon node explants were co-treated with sonication for 2 s and surfactant at 0.02% (v:v) using two different soybean genotypes, Jack and Zhonghuang 10. The improved transformation efficiency of this combination was also evaluated by development of herbicide-tolerant soybeans with transformation efficiency at 2.5–5.7% for different genotypes, which was significantly higher than traditional cotyledonary node method in this study. These results suggested that co-treatment with surfactant and sonication significantly improved the percentages of resistance bud formation, transient expression efficiency and stable transformation efficiency in soybean.

The objective of this study was to determine the efficiency of different plant systems in capturing deep soil nitrate (NO3 -) to reduce NO3 - leaching in a field plot experiment using 15N labelling. The study was conducted on a calcareous alluvial soil on the North China Plains and the plant systems evaluated included alfalfa (Medicago sativa), American black poplar (Populus nigra) and cocksfoot (Dactylis). 15N-labelled N fertilizer was injected to 90 cm depth to determine the recovery of 15N by the plants. With conventional water and nutrient management, the total recovery of 15N-labeled NO3 --N was 23.4% by alfalfa after two consecutive growth years. The recovery was significantly higher than those by American black poplar (12.3%) and cocksfoot (11.4%). The highest proportion of soil residual 15N from the labeled fertilizer N (%Ndff) was detected around 90 cm soil depth at the time of the 1st year harvest and at 110-130 cm soil depth at time of the 2nd year harvest. Soil %Ndff in 0-80 cm depth was significantly higher in the alfalfa treatment than those in all the other treatments. The soil %Ndff below 100 cm depth was much lower in the alfalfa than those in all the other treatments. These results indicated that 15N leaching losses in the alfalfa treatment were significantly lower than by those in the black poplar and cocksfoot treatments, due to the higher root density located in nitrate labeling zone of soil profile. In conclusion, alfalfa may be used as a plant to capture deep soil NO3 - left from previous crops to reduce NO3 - leaching in high intensity crop cultivation systems of North China Plain.