Cover illustration
Super hybrid rice breeding is a new breeding method combining semi-dwarf breeding and heterosis breeding using germplasm and gene-environment interactions. This paper reviews the breeding strategies of super hybrid rice breeding in China, focusing on the utilization of heterosis of indica and japonica subspecies, construction of ideal plant architecture and pyramiding of disease resistant genes in restorer lines. To develop super hybrid rice, considerable effort should be made to explore genes related with high yield, good quality, resistance to pests and diseases, tolerance to stresses. Molecular breeding methods in combination with crossing techniques should be adopted in super hybrid rice breeding.
Understanding of hydrological processes, including consideration of interactions between vegetation growth and water transfer in the root zone, underpins efficient use of water resources in arid-zone agriculture. Water transfers take place in the soil-plant-atmosphere continuum, and include groundwater dynamics, unsaturated zone flow, evaporation/transpiration from vegetated/bare soil and surface water, agricultural canal/surface water flow and seepage, and well pumping. Models can be categorized into three classes: (1) regional distributed hydrological models with various land uses, (2) groundwater-soil-plant-atmosphere continuum models that neglect lateral water fluxes, and (3) coupled models with groundwater flow and unsaturated zone water dynamics. This review highlights, in addition, future research challenges in modeling arid-zone agricultural systems, e.g., to effectively assimilate data from remote sensing, and to fully reflect climate change effects at various model scales.
The North China Plain (NCP) is a major grain production area in China, but the current winter wheat-summer maize system has resulted in a large water deficit. This water-shortage necessitates the improvement of crop water productivity in the NCP. A crop water model, AquaCrop, was adopted to investigate yield and water productivity (WP) for rain-fed summer maize on the piedmont of the NCP. The data sets to calibrate and validate the model were obtained from a 3-year (2011–2013) field experiment conducted on the Yanshan piedmont of the NCP. The range of root mean square error (RMSE) between the simulated and measured biomass was 0.67–1.25 t·hm−2, and that of relative error (RE) was 9.4%–15.4%, the coefficient of determination (R2) ranged from 0.992 to 0.994. The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm; and RE and R2 in the range of 1.07%–1.20% and 0.880–0.997, respectively. The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m−3. The simulated impact of long-term climate (i.e., 1980–2010) and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater, and much lower values elsewhere. The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem, thus a beneficial outcome for both food and ecosystem security can be assured.
Previous studies indicated that miR-29c is important for muscle development in mice and human, but its role in pigs is unknown. In this study, we detected the expression of miR-29c in Meishan longissimus lumborum (LL) muscle. The results showed that miR-29c was gradually upregulated during development of skeletal muscle in pig. Moreover, the expression of YY1 and Akt3 genes, which were confirmed to be targeted by miR-29c in mice, was decreased along with muscle development. Furthermore, the expression level of miR-29c was significantly higher in adult Meishan pigs than Large White pigs, while the expression of YY1 and Akt3 genes was significantly lower in Meishan pigs. These results indicated that the expression pattern of miR-29c was opposite to that of YY1 and Akt3 genes in pigs. Also, the luciferase assay indicated that miR-29s can target the YY1 gene in pigs. In addition, we identified a T to C mutation in the primary transcript of miR-29c, which was associated with the postmortem muscle pH in pigs. Based on these results, we concluded that miR-29c is also important in skeletal muscle development of pigs.
Garlic (Allium sativum, Liliaceae) has been safely used for more than 5000 years, and research on garlic extract is rapidly increasing because of its multiple biological functions. The in vivo effects of oral administration of garlic mixture (GM, water-soluble extract) on infectious bursal disease virus (IBDV)-infected specific pathogen free male white leghorn chicken were examined through histopathological, immunohistochemical, and Western blot analyses, and enzyme-linked immunosorbent assay. The results confirmed the protective effects of oral administration of 5 mg·kg−1 BW GM (Group GM1) on bursal lesions after IBDV infection. In particular, protein expression of IBDV in the bursa decreased in Group GM1, indicating that GM administration decreased IBDV replication in the bursa. Furthermore, immunoglobulin M- and A-bearing B lymphocytes significantly increased 7 days post infection in bursae in Group GM1 (P<0.01), suggesting that the oral administration of 5 mg·kg−1 GM offers moderate protection against B cell destruction after IBDV infection. During infection, the concentration of bursal interferon gamma (IFN-g) increased and peaked in Group GM1 earlier than in Group T (IBDV-exposed), demonstrating that GM administration prompted the production of IFN-g to protect against IBDV infection.
Canadian goldenrod (Solidago canadensis) is one of the most destructive invasive weeds in South-eastern China. To evaluate its potential application as dietary supplement in red swamp crayfish (Procambarus clarkii), the antibacterial properties of aqueous and ethanol extracts of this plant against three major pathogenic bacteria in crayfish aquaculture were examined. Inhibition zone tests and determination of minimum inhibitory concentration revealed that the extracts had lower antibacterial activity than extracts from two traditional medicinal plants that possess antibacterial properties, garlic (Allium sativum) and cortex phellodendri (Phellodendron chinense). However, they did exhibit greater antibacterial effects than extracts from another widely used medicinal plant, Sophora flavescens, and an aquatic weed, Alternanthera philoxeroides. Aqueous extracts of Canadian goldenrod gave greater inhibition than the ethanol extracts. Crayfish fed a diet with 2% these aqueous extracts exhibited significantly higher enzyme activity of alkaline phosphatase, catalase and phenoloxidase (P<0.05). Based on the results of this study, we conclude that aqueous extracts of Canadian goldenrod are highly promising for the development of new dietary supplement for use in crayfish aquaculture.
Twelve (+)-nopinone-based 2-amino-3-cyanopyridines 4a–l were synthesized from (–)-β-pinene. The structures of these compounds were characterized by FT-IR, 1H NMR, and ESI-MS. All the compounds were tested for their anticancer activity against lung cancer cell line A549, gastric cancer cell line MKN45 and breast cancer cell line MCF7 by MTT method, respectively. The results showed that compounds 4f, 4j and 4k had promising anticancer activity against these cancer cell lines, in particular, compound 4f exhibited broad-spectrum and highly efficient anticancer activity against cell lines A549, MKN45 and MCF7 with IC50 of 23.78, 67.61 and 53.87 µmol·L−1, respectively. The preliminary analysis of the structure activity relationship implied that the Br or Cl substituted group of the benzene ring in these derivatives significantly contributed to the anticancer activity.
Electromagnetic wave pollution has attracted extensive attention because of its ability to affect the operation of electronic machinery and endanger human health. In this work, the environmentally-friendly hybrid aerogels consisting of cellulose and multi-walled carbon nanotubes (MWCNTs) were fabricated. The aerogels have a low bulk density of 58.17 mg·cm−3. The incorporation of MWCNTs leads to an improvement in the thermal stability. In addition, the aerogels show a high electromagnetic interference (EMI) SEtotal value of 19.4 dB. Meanwhile, the absorption-dominant shielding mechanism helps a lot to reduce secondary radiation, which is beneficial to develop novel eco-friendly EMI shielding materials.
It is imperative to carry out research on residual plastic film collection technology to solve the serious problem of farmland pollution. The residual plastic film baler was designed as a package for film strip collection, cleaning and baling. The collection device is a core component of the baler. Response surface analysis was used in this study to optimize the structure and working parameters for improving the collection efficiency of residual film and the impurity of film package. The results show that the factors affecting the collection rate of residual film and the impurity of the film package are the speed ratio (k) between the trash removal roller and eccentric collection mechanism, the number (z) and the mounting angle (θ) of spring teeth in the same revolution plane. For the collection rate, the importance of the three factors are in the order, k>z>θ. Meanwhile, for the impurity, the importance of three factors are in the order, z>k>θ. When the speed ratio, the mounting angle and the number of spring teeth was set at 1.6°, 45°, and 8°, respectively, the collection rate of residual film was 88.9% and the impurity of residual film package was 14.2% for the baler.