“十三五”国家重点研发计划“七大农作物育种”重点专项管理经验与科技创新进展

国家重点研发计划“七大农作物育种”重点专项实施以来,专业机构建立了一套突出绩效导向的专业化管理模式,最大限度释放创新活力,营造良好创新生态,推进专项一体化实施。专项重点突破基因挖掘、品种设计和种子质量控制等核心技术,获得一批具有育种利用价值和知识产权的重大新基因,创制一批优异新种质,并形成高效育种技术体系,为保障国家粮食安全和促进农业绿色发展提供了强有力的科技支撑。总结介绍了育种专项的管理经验和创新成效,并对种业科技未来发展和组织管理提出对策建议。     

赤霉酸对杂交水稻种子淀粉酶同工酶形成的调节机理研究初报

 以杂交水稻汕优6号和对照品种广陆矮4号为材料，通过GA3和放线菌D处理研究了水稻种子淀粉酶同工酶的特征。结果表明，杂交水稻种子中出现的淀粉酶同工酶对GA3反应不同，其中α-淀粉酶（A带）和β-淀粉酶（B带）都不受GA3的影响，而另一条α-淀粉酶（C带）则依赖于GA3的诱导。表明不同的α-淀粉酶同工酶的合成有着不同的调节机理。另外，RNA合成的专一抑制剂对α-淀粉酶同工酶的形成无影响。推测水稻种子可能预存有相应的mRNA，在萌发时通过GA3的激活而诱导α-淀粉酶的生物合成。     

Comparison of soil preparation methods for rice production in the Middle Nile Delta,Egypt

Field experiments were conducted during the summer seasons of 2011 and 2012 in the Middle Delta of Egypt to compare alterations in saving water and grain yield of transplanted rice in clay loam soil after compaction, wet tillage (puddling) and dry tillage (non-puddling). The results indicate that compacted soil gave higher grain yield, higher irrigation water productivity, higher net income, higher benefit–cost ratio, and less water consumption than wet and dry tillage. The results suggest that soil compaction by four passes of steel plank (2 m long and 600 kg weight) before planting rice is beneficial in terms of saving water and net return. In addition, it can be used instead of the non-puddling method under the conditions of the studied area. Therefore, soil compaction can be considered as a pioneering method of pre-planting soil preparation to increase rice yield and to save irrigation water. It is highly recommended to be used by farmers.     

Long-term gravel–sand mulch affects soil physicochemical properties,microbial biomass and enzyme activities in the semi-arid Loess Plateau of North-western China

The use of gravel–sand mulch is a traditional water-conservation technique in the semi-arid Loess Plateau of North-western China. In this study, we investigated the 16-year effects of this mulch on soil physicochemical properties (total organic C, N and P; bulk density; Ca, Cu, Fe, Mg, Mn and Zn; soil texture; pH), microbial biomass C, N and P and enzymatic activities (peroxidase, dehydrogenase, invertase, β-glucosidase, alkaline phosphomonoesterase and urease) in a field trial in China's Gaolan County. We examined how these parameters changed after 7, 11 and 16 years of mulching. After 16 years, soil bulk density and sand content increased significantly. Soil Ca and Cu contents did not change significantly during the study period, but Fe, Mg, Mn and Zn contents all decreased significantly after 16 years. The total N increased significantly after 11 years, but total C and N both decreased dramatically and significantly after 16 years (by 22% and 13%, respectively, compared to the control). The mulch significantly increased microbial biomass C (by 29% after 11 years), with similar results for N and P, but these positive effects were lost after 16 years. Enzyme activities revealed changes in the soil microbial community over time; the mulch increased enzyme activities until 11 years, followed by a significant decrease that suggested degradation of soil quality after long-term mulching. The positive effects of the mulch (increasing soil temperature) could explain the high microbial biomass and enzyme activities after 11 years. However, long-term increases in soil bulk density and sand content (caused by mixing of the mulch layer with the surface soil) and a lack of inputs of organic matter (caused by the barrier created by the mulch layer) led to degradation of the soil after 16 years.     

Succinic acid inhibited growth and pathogenicity of in vitro soil-borne fungus Fusarium oxysporum f. sp. niveum

Abstract

To clarify possible mechanisms of interaction of soil–plant–microbe for fusarium wilt of watermelon, succinic acid was added into the media to test its effect on in vitro Fusarium oxysporum f. sp. niveum in the ecological and biogeochemical cycling of soil–plant–microbe. Results showed that succinic acid decreased the growth and conidia germination of Fusarium oxysporum f. sp. niveum. The biomass and the conidia germinating rate were reduced by 10.1–59.8% and 14.4–21.4% respectively. Mycotoxin production and pathogenic enzyme activity by the fungus were suppressed at higher concentrations of succinic acid. Results suggested that succinic acid would not increase the risk of Fusarium oxysporum attacking plants, animals and humans due to its inhibition of fungus in the ecological and biogeochemical cycling of succinic acid in the interaction of soil–plant–microbe.     

地膜覆盖滴灌棉田土壤上水分动态的数值模拟

Drip irrigation under plastic mulch has been widely applied in arid Northwest China as a water-saving irrigation technology.A comprehensive knowledge of the distribution and movement of soil water in root zone is essential for the design and management of irrigation regimes.Simulation models have been proved to be efcient methods for this purpose.In this study,the numerical model Hydrus -2D was used to simulate the temporal variations of soil water content in a drip irrigated cotton field under mulching.A concept of partitioning coefcient,calibrated to be 0.07,was introduced to describe the efect of plastic mulch on prevention of evaporation.The soil hydraulic parameters were optimized by inverse solution using the field data.At the optimized conditions,the model was used to predict soil water content for four field treatments.The agreements between the predictions and observations were evaluated using coefcient of determination (R2) and root mean square error (RMSE).The results suggested that the model fairly reproduced the variations in soil water content at all locations in four treatments,with R2 ranging from 0.582 to 0.826 and RMSE from 0.029 to 0.050 cm3 cm-3,indicating that the simulations agreed well with the observations.     

Comparison of statistical models for predicting cost effective nitrogen rate at rice–wheat cropping systems

Due to increased economic and environmental concerns, developing statistical models of crop yield has become one of the most important steps in determination of the cost effective rates (CERs) of nitrogen (N) fertilization. Although quadratic models are commonly used to describe wheat and paddy rice yield response to fertilizer rates in the Taihu Lake region of China, few studies have investigated why this model is selected over others. This study evaluated quadratic, exponential and square root models describing the wheat (Triticum aestivum L.) and rice (Oryza sativa L.) yield response to N fertilizer when determining the CERs, while also considering the environmental costs of N losses. All models fit the data almost equally well when evaluated using the variability and standard error statistics. However, there were marked discrepancies among models when calculating the CER of fertilization and the economic returns form Z-test. The quadratic model had a greater CER value (194?kg N ha^–1 for rice and 185?kg N ha^–1 for wheat) averaged over all sites than the exponential and square root models. The residuals obtained from the quadratic models were closer to a normal distribution than those of the other two models, indicating a less systematic bias. The mean economic uncertainties resulting from the quadratic model were more dependable than the other two models evaluated. These results show that the quadratic model best describes the rice and wheat yield responses and tends to indicate the optimal rates of fertilization while considering the environmental and economic effects of over fertilization for rice and wheat in the Taihu Lake region.     

汶川震区滑坡堆积体体积三维激光扫描仪测量与计算方法

2008年5.12汶川8级地震形成的大量松散滑坡堆积体,破坏农用地,损毁农田基础设施,对震区农业经济造成重大损失,严重威胁震区农业生产安全。本研究所选震区典型滑坡堆积体位于汶川县草坡乡,采用三维激光扫描仪实地测量滑坡堆积体,构建滑坡堆积体几何模型,计算滑坡堆积体体积。扫描仪到滑坡堆积体前、后缘的距离分别为25.74和79.00 m,距离扫描仪200 m处的扫描精度为20.0 cm×20.0 cm。根据扫描得到的滑坡堆积体点云数据,采用特征值法拟合近似滑坡堆积体的坡面、滑动面,构建滑坡堆积体几何模型。计算得到该滑坡堆积体体积为19 018 m3。建立了使用三维激光扫描仪测量和计算滑坡堆积体体积的方法。这种测量与计算方法可为地震受损农用地灾后的土地整理提供重要依据。     

Aluminum status of synthetic Al–humic substance complexes and their influence on plant root growth

Abstract

Aluminum (Al)–humus complexes are abundant in the A horizons of non-allophanic Andosols and contribute to the unique properties of volcanic ash soils, such as high reactivity with phosphate ions and a low bulk density. Natural non-allophanic Andosols commonly show Al toxicity to plant roots. There have been very few studies examining the contribution of Al–humus complexes to the Al toxicity of plant roots, although the complexes are the probable source of the toxic Al. We extracted humic substances from the A horizon of a non-allophanic Andosol using NaOH solution and reacted the humic substances and partially neutralized the AlCl₃ solution at three pH conditions (pH 4.0, 4.5 and 5.5) to prepare pure Al–humic substance complexes. The Al solubility study (equilibrium study in 10^?2 mol L^?1 CaCl₂) and the Al release study (a stirred-flow method using 10^?3 mol L^?1 acetate buffer solution adjusted to pH 3.5) indicated that all the synthetic complexes easily and rapidly release monomeric Al into the liquid phase with slight changes in pH and ion strength, although the Al contents and their extent of polymerization are considerably different among the complexes. A plant growth test was conducted using a medium containing the Al–humic substance complexes and perlite mixture. Root growth in burdock (Arctium lappa) and barley (Hordeum vulgare L.) was reduced equally by all three complex media, and the roots showed the typical injury symptoms of Al toxicity. These results indicate that in soils dominated by Al–humus complexes the Al released from the Al–humus complexes, as well as the exchangeable Al adsorbed by soil minerals, is definitely toxic to plant roots.