杂交水稻新组合选育若干问题的初步探讨

选育优势更强,产量更高的杂交水稻组合,首先必须对产生杂种优势的遗传基础理论以及抗性等问题有个正确的认识。为此笔者结合几年来的工作实践并参照前人的试验结果,对杂交水稻强优势组合选育的若干问题进行初步探讨。一、扩大遗传差异与杂种优势问题。杂种优势与双亲性状遗传距离的大小有密切关系,双亲遗传距离大,杂种优势强;双亲遗传距离小杂种优势不强[1]。在杂交水稻新组合的选育中,我们需要采用恢×恢、恢×保选育新的恢复系,配组的杂交水     

水稻品种ZH5及其杂交后代纹枯病抗性和农艺性状研究

以对纹枯病（Rhizoctonia solaniKühn）有良好抗性的水稻品种ZH5为母本,与对纹枯病抗性较差的泸恢17、多系1号和GR83个恢复系进行杂交,获得杂交F1、F2代,于2005—2006年在杭州田间对亲本和杂交后代进行了纹枯病抗性人工接种鉴定及植株生物学性状考查。结果表明,杂交F1代植株对纹枯病的抗性水平介于双亲之间,大多数农艺性状表现出超亲优势或介于双亲之间;同一杂交组合F2代群体内纹枯病抗性分离较大;不同杂交组合间群体内抗、感纹枯病植株分布差异较大。植株对纹枯病的抗性与株型性状相关不显著,主要决定于品种自身的抗性遗传背景。     

水稻优质抗稻瘟病新种质的创制

为了创制优质抗稻瘟病水稻新材料,研究以抗稻瘟病、恶白粒率低,碱消值高的种质资源IR79193-83-1-1-1为供体亲本,与强恢复系帮恢609为受体亲本进行杂交,对分离世代进行连续的功能标记辅助选择、米质外观、碱消值测定、稻瘟病抗性鉴定等的综合筛选,获得5份稻瘟病抗性强(均携带Pi9和Pi5抗性基因),综合农艺性状好,恶白粒率低,碱消值高的优质恢复系新材料,为杂交水稻新品种选育和种质创新提供材料。     

晚杂优恢复系及其强优组合选育浅见

在汕优63大面积推广的基础上,要把水稻单产推向一个更高的水平,已成为水稻育种家致力探求的问题。本文结合晚杂优的育种实践,对杂交晚稻恢复系及其强优组合的选育提出一些看法,供参考。一、人工制恢选育晚稻恢复系 (一)关于品种资源的征集及亲本选配晚杂优恢复系的选育,应十分注意搜集利用以下几方面的材料。 1.选用强恢复力的早、晚熟材料作亲本,以选育具有强恢复力的晚稻恢复系。 2.利用自己育成的中间材料作亲本,用已有丰富遗传基础的中间材料(即综合性状     

大穗型水稻恢复系绵恢523的选育与应用

绵恢523是绵阳市农业科学研究院以内恢99-14为母本、(蜀恢881/千粒稻)F₁为父本杂交后经系谱法选育而成的杂交水稻中籼迟熟大穗型恢复系,具有农艺性状优良、抗性较好、恢复力强、配合力高等特点。绵恢523所配组合绵优5323、蓉7优523、荃优523、金博优3523先后通过省级或国家农作物品种审定。     

籼粳交杂种优势利用的初探

杂种优势与双亲性状遗传距离的大小有密切关系,双亲遗传距离大、杂种优势强、双亲遗传距离小、杂种优势不强〔1〕。目前缺乏多类型的矮源和恢保源。早稻野败型不育系基本上是矮仔占和矮脚南特的血缘,而恢复系基本上来自皮泰的血缘。这些品种左种右配,亲缘重叠、由于双遗传差异不大、尽管花了大量时间和人力,至今尚未获得较现有杂交水稻增产显著的强优组合。不少学者提出通过寻找新质源和新恢源以及利用籼粳杂交优势,用籼不粳恢或粳不籼恢等途径来选配强优组合。籼粳稻杂交杂种表现强大     

水稻广谱恢复系R1990选系的配合力研究

配合力是衡量杂交水稻亲本应用价值的主要标准.R1990是由分子标记辅助选择技术选育的广谱恢复系,为探究其品质改良选系的配合力表现,试验采用不完全双列杂交设计,以3个R1990选系及其亲本9311、蜀恢527为恢复系,与4个三系不育系、3个两系不育系进行配组,并对组合的产量性状进行配合力分析.结果 表明,R1990选系所...     

北方杂交粳稻的食味品质与其亲本的相关性研究

以4个不育系和5个恢复系及其所配20个杂交组合为材料,研究了杂交粳稻的食味品质相关性状与其亲本的关系。结果表明,供试亲本间整精米率、蛋白质含量和糊化特性值均存在显著差异,从平均值来看,恢复系的整精米率高于不育系,而食味及其相关性状不如不育系,杂交组合的各项指标偏向于恢复系;整精米率、垩白米率、碎米率、蛋白质含量、食味评分、最高粘度、最低粘度、崩解值以及米饭的粘度、味道综合评价值等性状在恢复系与杂交组合间以及双亲均值与杂交组合间均呈显著或极显著正相关,而各性状在不育系与杂交组合间的相关性均不显著。要提高杂交粳稻的食味品质,应重点选育蛋白质含量低、糊化特性好和食味优的恢复系。     

重穗型籼稻迟熟恢复系泸恢23的选育与应用

泸恢23系四川省农科院水稻高粱研究所用泸恢602与万恢88的杂交后代与绵恢725杂交后系谱选择育成的重穗型迟熟恢复系,具有农艺性状优良、稻米品质较优、抗性较强、恢复力强、配合力高等特点。该恢复系所配组合川谷优23丰产、稳产性较好,适应性广,于2015年通过国家品种审定。     

优质高产弱感光型杂交水稻新品种博优双青

博优双青是广东省信宜市农业科学研究所利用不育系博A，与自选恢复系信恢双青配组而成的弱感光型优质杂交晚稻新组合。父本信恢双青是本所于2001年用新青928与山青11杂交，经过3年5代系统选育成的综合农艺性状突出、米质优良、抗病性强、性状稳定的恢复系。于2004年春季与博A配组，经多年优势鉴定，博刖信恢双青综合性状较好，表现出米质优、口感佳、产量高、抗性强、适应性广等特点。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.