Super Rice Cropping Will Enhance Rice Yield and Reduce CH4 Emission： A Case Study in Nanjing,China

A pot experiment was performed to learn the differences in plant productivity and OH4 emission between two rice cultivars, super rice variety Ningjing 1 and traditional variety Zhendao 11, which were currently commercially appUed in Nanjing, China. Similar seasonal changes of CH4 emission fluxes and soil solution CH4 contents were found between the tested cultivars. Although there was no significant difference in plant biomass production between the cultivars, the grain yield of Ningjing 1 was significantly higher by 35.0% （P 〈 0.05） than that of Zhendao 11, whereas the total CH4 emission from Ningjing 1 was 35.2% lower （P 〈 0.05）. The main difference in the amounts of CH4 emission between the cultivars occurred in the period from the tillering stage to the heading stage. The biomass-scaled and yield-scaled CH4 emissions were respectively 3.8 and 5.2 mg/g for Ningjing 1, significantly lower than those for Zhendao 11 （7.4 and 12.8 mg/g, respectively）. According to the relationships between the plant growth characteristics and the CH4 emission, a stronger root system contributed mainly to the lower CH4 emission of Ningjing 1, as compared with Zhendao 11. Our results demonstrated that super rice has advantages not only in grain productivity but also in CH4 emission mitigation. Further expansion of super rice cropping will enhance rice yield and reduce greenhouse gas emission in China.     

Morphological and Anatomical Assessment of KDML 105 (Oryza sativa L.spp.indica) and Its Mutants Induced by Low-Energy Ion Beam

Thai jasmine rice KDML 105 is consumed around the world.BKOS,PKOS and TKOS are new cultivars produced from low-energy ion beam induction in KDML 105.The purpose of this study is to compare the morphology and anatomy between KDML 105 and the three new cultivars.Seeds of the four cultivars were germinated and grown in pots until flowering phase.The plants’ organs were observed and the lengths of culms,ligules,leaves and panicles were measured.Leaf surface area was calculated and numbers of roots,spikelets and tillers were counted.BKOS and PKOS had significantly shorter culms than KDML 105 and TKOS.The largest leaf area was found in KDML 105 followed by TKOS,BKOS and PKOS,respectively.Numbers of roots and tillers in BKOS and TKOS were significantly fewer than those in KDML 105 and PKOS.The number of spikelets per plant in BKOS was the lowest among all cultivars.For anatomical comparison,cross sections of culms and roots were observed.All plants had a similar arrangement of tissues,but the number and size of cells were different.Furthermore,longitudinal sections of culms showed that the lengths of epidermal and parenchyma cells were directly related with the length of the culm.To compare the leaves,both stomata and epidermal cells were counted and the lengths of the guard cells were measured.The lengths of guard cells of BKOS and PKOS were shorter,but the stomatal density and the stomatal index were significantly greater than those of KDML 105.For TKOS,though the length of guard cells was shorter than that in KDML 105,the difference was not significant.However,the stomatal density and stomatal index were significantly higher than those in KDML 105.     

Workshop on Simulation and Systems Analysis for Rice Production(SARP) held at CNRRI

SARP Workshop on risk analysis of agroecological zonation and optimization of crop rotation was held at CNRRI's research center on 24—27 Oct, 1995. Experts from Philippines, India, China, and IRRI were present in the workshop. Participants exchanged the research results on the field of land use, soil erosion. optimization of rice—wheat, rice—peanut, rice—corn cropping system in the different environments, risk analysis of rice based cropping system, nitrogen balance in rice based cropping system with system approach, demonstrated models used in their studies, and discussed the ongoing cooperative research.     

Genetic analysis of blast resistance On rice cultivars with wide—spectrum resistance

In recent years,indirect selection based ontightly linked genetic markers has been sug-gested to pyramid the resistance genes.How-ever,resistance parents used in the linkagestudies were usually near isogenic lines possessing a single resistance gene derived fromthe original resistance donor.Little was knownon the interaction among the genes at differentloci.In the present study,the genetic controlof blast resistance in two wide—spectrum re-vistance rice cultivars was analyzed.A susceptible indica varieties Xianfenglwas used as the female parent,and the blastresistance cultivars Tetep and Hongjiaozhanwere used as the male parents.The threeparental lines were inoculated with each of 20races of Pyricularia oryzae Cav at tilleringstage.The race ZC_(13) was selected to inoculatethe 161 F_3 lines of Xianfeng1/Tetep and 175 F,lines of Xianfengl/Hongjiaozhan.Eighteen in-dividuals of each line were inoculated.In both populations,all the individualsdemonstrated extreme reaction to the blast dis-ease.In the F_3 po     

Interpreting genotype × environment interactions for grain yield of rainfed durum wheat in Iran

Clustering genotype × environment(GE) interactions and understanding the causes of GE interactions are among the most important tasks in crop breeding programs. Pattern analysis(cluster and ordination techniques) was applied to analyze GE interactions for grain yield of 24 durum wheat(Triticum turgidum L. var. durum) genotypes(breeding lines and old and new cultivars) along with a popular bread wheat(Triticum aestivum) cultivar grown in 21 different rainfed environments during the 2010–2013 cropping seasons. To investigate the causes of GE interaction, several genotypic and environmental covariables were used. In a combined ANOVA, environment was the predominant source of variation,accounting for 81.2% of the total sum of squares(TSS), and the remaining TSS due to the GE interaction effect was almost seven times that of the genetic effect. Cluster analysis separated the environments into four groups with similar discriminating ability among genotypes, and genotypes into five groups with similar patterns in yield performance.Pattern analysis confirmed two major environmental clusters(cold and warm), and allowed the discrimination and characterization of genotype adaptation. Within the cold-environment cluster, several subclusters were identified. The breeding lines were most adapted to moderate and warm environments, whereas the old varieties were adapted to cold environments. The results indicated that winter rainfall and plant height were among the environmental and genotypic covariables, respectively, that contributed most to GE interaction for grain yield in rainfed durum wheat.     

Screening of Rice Cultivars for Morpho-Physiological Responses to Early-Season Soil Moisture Stress

The majority of rice(Oryza sativa L.) produced in the southern USA is drill-seeded and grown under upland-like conditions because permanent flooding is established after the four-leaf stage. Therefore, rice during the seedling growth stage will be subjected to variable soil moisture content. A greenhouse experiment was conducted to evaluate the performance of 15 rice cultivars commonly grown in Mississippi of USA under early-season soil moisture stress. Twenty morpho-physiological parameters of rice seedlings subjected to three different levels(100%, 66% and 33% field capacity) of soil moisture, from 10 to 30 d after sowing, were measured. Significant moisture stress × treatment interaction(P 0.001) was observed for most of the parameters. Further, the total drought response index(TDRI) was developed to score the cultivars for drought tolerance with the variation from 26.88 to 36.21. Accordingly, the cultivars were classified into different groups of tolerance. The cultivars CL152 and CL142-AR were classified as the least and the most tolerant to drought based on TDRI and standard deviation, respectively. Even though both total root(R~2 = 0.98) or shoot(R~2 = 0.76) drought responses indices were positively correlated with TDRI, root traits were important in deriving the indices. Therefore, TDRI could be used to select cultivars for drought tolerance in a given environment and develop rice varieties with early-season drought tolerance. However, further research is needed to identify and characterize tolerance at other stages to assist breeding programs in rice.     

Genetic Structure and Indica/Japonica Component Changes in Major Inbred Rice Varieties in China

We used 39 SSR markers to analyze the genetic structure of 304 major Chinese inbred rice varieties, and to compare changes in the indica or japonica components in these varieties that have been widely cultivated from the 1950s to the 1990s in China. The genetic structure analysis showed that these rice varieties were distinctly divided into two populations, indica and japonica. The sub-structure of indica varieties was more complex than that of japonica ones. Among the various lines, late-season indica and early season japonica varieties had simpler genetic backgrounds. The seasonal ecotypes were not quite consistent with the subtypes of genetic structure. Twelve SSR loci with specific differentiation between indica and japonica were used to calculate the indica/japonica components. The differences in indica/japonica components among the five decades were not significant, except for late-season indica varieties in the 1990s, which had a significantly higher japonica component. These results will help to understand the genetic structure of the major Chinese inbred rice varieties and will be useful for indica-japonica hybrid breeding in China.     

Genetic Analysis of Early Generation Stability in Rice

The mechanism of early generation stability （EGS） in rice was studied via genetic analysis. Three types of crosses were made, namely between EGS varieties, EGS and conventional rice variety, and conventional rice varieties. The genetic analysis was based on the stable lines in F2 population. The stable lines may appear from some combinations of EGS rice crossing with each other and EGS rice crossing with conventional varieties at different frequencies, but stable lines didn＇t appear in conventional varieties crossing with conventional varieties. Genetic analysis results indicated that the EGS phenomena should just exist in special rice materials, and the frequency of stable lines was closely related to the EGS traits of parents. The EGS traits were neither qualitative nor quantitative traits, and they were controlled by neither dominant genes nor recessive genes. The EGS traits might be inherited by F1 single plant, and the traits of F3 and F4 were corresponded to those of F2 population, i.e. F3 and F4 lines derived from non-segregating F2 showed uniform agronomic traits, and those from segregating F2.did not. The agronomic traits of EGS lines were consistent with those of F1 single plant. On the other hand, when EGS lines occurred, the segregating lines in Mendelian manner were also observed in all F2 population of the same combination. It was suggested that the reason why the stable strains occurred might be a special factor to control （open/close） gene at the beginning of cell division in zygote, resulting in closing mitosis and opening somatic reduction. The somatic reduction of zygote resulted in recombination and homozygosity forming in F1 single plant, and some lines with uniform agronomic traits were observed in some lines of F2 population.     

Genetic Analysis of Heading Date of Japonica Rice Cultivars in Southwest China

Heading date of 26 native japonica rice cultivars in southwest China was investigated,and their basic vegetative growth(BVG),photoperiod-sensitivity(PS) and temperature-sensitivity(TS) were analyzed under artificial short-day and natural long-day conditions in Nanjing,as well as artificial high-temperature and natural low-temperature conditions in winter in Hainan.The results showed that the PS and TS varied among different cultivars.The BVG of all the japonica cultivars was well situated,but differed withi...     

玉米鞘腐病原菌生物学特性研究

The newly occurred corn disease,sheath rot of corn,the biological characteristics of the disease causal agent Fusarium proliferatum(Mats.) Nirenberg was studied.The results indicated that the optimum temperature for the pathogen growth and both microconidia and macroconidia germination ranged 25℃-30℃.The optimum pH values for the pathogen growth was 5-6,Chlamydospores were produced from mycelia and macroconidia on PSA medium after 10-12 days cultured.The pathogen grew better in many kinds of sugar as the carbon sources,such as sucrose,dextrose,xylose,galactose,lactose,and starch and sorbose take the second place.And the fungus grew better in many kinds of nitrogen sources,such as beef extract,yeast extract,potassium nitrate,ammonium chloride,ammonium sulfate,potassium nitrate.The medium which only contained nitrogen sources was not in favour of the pathogen growth.The optimum medium for pathogen growth was Richard's;PDA,PSA,corn flour,oatmeal and the colony were different in color.     

兜兰离体快繁技术研究进展

由于生境破坏和人工过度采挖及繁殖的障碍,兜兰已是世界上最濒危的植物物种之一,所有野生种均被列入《濒危野生动植物种国际贸易公约》附录I而被禁止交易。突破其种苗繁殖技术瓶颈有利于兜兰种质资源的保护和可持续利用。本文对兜兰属植物无菌播种、共生萌发和组织培养技术等离体快繁技术的进展进行综述,并提出了目前存在的问题和解决方法,以期为兜兰属植物离体繁殖技术的深入研究和优质种苗的规模化生产提供参考。     

High variation in frequency of infection by endophytes in cultivars of meadow fescue in Finland

Systemic and asymptomatic Neotyphodium fungal endophytes infect numerous species of the Poaceae. The frequencies of Neotyphodium endophyte infection in Finland were investigated among and within seven Nordic cultivars of meadow fescue, Schedonorus pratensis (Huds.) P. Beauv., which is a widely grown pasture and forage grass species in Scandinavia. The cultivars were Kasper, Salten, Antti, Fure, Ilmari, Inkeri and Kalevi. Frequencies of infection of cultivars varied from endophyte-free cultivar Fure to highly infected cultivar Inkeri [mean (standard deviation of mean) of 0·95 (0·023)]. Mean frequencies of infection of three cultivars remained lower than 0·10, and two of the cultivars, Kasper and Salten, were intermediately infected. In most of the cultivars, frequencies of infection varied only slightly among seed lots. In cultivar Kasper, however, the frequency of endophyte infection was highly variable (0–0·96) among the 45 seed lots examined. The relative importance of cultivar, seed lot and infection by Neotyphodium endophyte to the aphid Rhopalosiphum padi L. was studied experimentally, using both endophyte-free and endophyte-infected plants of four seed lots of the two intermediately infected cultivars. Endophyte infection increased plant resistance to R. padi , overriding the influences of seed lot and cultivar. It is proposed that variation caused by endophyte infections in cultivars of meadow fescue should be taken into account in assessing plant breeding programmes in Europe.     

Investigation of Polymorphisms in Coding Region of OsHKT1 in Relation to Salinity in Rice

Rice(Oryza sativa) is sensitive to salinity, but the salt tolerance level differs among cultivars, which might result from natural variations in the genes that are responsible for salt tolerance. High-affinity potassium transporter(HKTs) has been proven to be involved in salt tolerance in plants. Therefore, we screened for natural nucleotide polymorphism in the coding sequence of Os HKT1, which encodes the HKT protein in eight Vietnamese rice cultivars differing in salt tolerance level. In total, seven nucleotide substitutions in coding sequence of Os HKT1 were found, including two non-synonymous and five synonymous substitutions. Further analysis revealed that these two non-synonymous nucleotide substitutions(G50T and T1209A) caused changes in amino acids(Gly17Val and Asp403Glu) at signal peptide and the loop of the sixth transmembrane domain, respectively. To assess the potential effect of these substitutions on the protein function, the 3D structure of HKT protein variants was modelled by using PHYRE2 webserver. The results showed that no difference was observed when compared those predicted 3D structure of HKT protein variants with each other. In addition, the codon bias of synonymous substitutions cannot clearly show correlation with salt tolerance level. It might be interesting to further investigate the functional roles of detected non-synonymous substitutions as it might correlate to salt tolerance in rice.     

彩叶植物在海南园林中的应用

彩叶植物在园林造景中日益受到重视。本文介绍彩叶植物的定义与分类,阐述其在园林中的应用原则,探讨适宜在海南园林中栽植的彩叶植物,以期彩叶植物在海南园林建设中发挥重要作用。     

5个马铃薯品种组培幼苗的磷效率差异研究

试验以5个生产用马铃薯品种脱毒试管苗为材料,采用组织培养的方法,初步研究了茎切段在正常磷及低磷培养基中生长30 d时幼苗的磷营养效率差异,为筛选出适宜于生产用的磷高效马铃薯品种奠定了基础。试验结果表明,5个马铃薯品种幼苗在正常磷和低磷胁迫下对磷素的吸收和利用能力均存在明显的基因型差异。利用各品种幼苗的磷效率指标(植株干重、鲜重、吸磷量、磷利用效率)的相对指标(低磷处理的结果/正常磷处理的结果×100)进行聚类分析(类平均法)的结果表明,大白和I-1035属于磷高效基因型品种,中农Ⅷ是磷低效基因型品种,凉薯97和疫不加则属于中间类型品种。     

我国香蕉深加工问题探讨

发展香蕉深加工是发展香蕉产业的重要途径。本文阐述香蕉的营养价值和经济价值，综述香蕉深加工研究进展，指出香蕉深加工中存在的问题，并提出发展对策。     

植物耐盐性研究进展

盐胁迫损害植物质膜的正常功能,造成植物气孔关闭,光合降低,耗能增加,养分离子吸收不平衡.目前已从许多植物中分离了一些盐胁迫诱导的基因及基因上游序列,但对植物耐盐分子机理尚未完全阐明,主要有渗透调节、拒盐机理、盐的区隔化、钾离子运输调控系统、水通道蛋白和光合途径改变等几种假说,有些耐盐基因已被成功转入植物中.研究表明,添加一些外源物质能提高植物的耐盐性。     

凉山州安宁河谷地带早春马铃薯品种的筛选

选择近年在安宁河谷地带种植观察表现产量高、品质好的凉薯97、会-2、抗青9-1、丽薯6号、米拉、川凉薯5号共6个品种进行了早春马铃薯品种筛选试验。结果表明:在安宁河谷地带选择会-2、川凉薯5号、抗青9-1和丽薯6号4个品种种植均可获得较高产量和产值。     

玉米耐盐性研究进展

综述了玉米耐盐生理机制和耐盐育种的研究进展。     

新疆伊犁地区亚麻田杂草调查

采用倒置“W”9点取样法对新疆亚麻主栽区——伊犁地区亚麻田进行了杂草调查。结果表明伊犁地区亚麻田的杂草有15科26种，单子叶杂草狗尾草、稗草、野燕麦，双子叶杂草灰绿藜、卷茎蓼的相对多度在20以上，是亚麻田杂草的优势种群。