不同基本苗对‘南粳51’产量及其构成的影响

合理的群体结构是水稻产量提高的基础,水稻基本苗是调节水稻群体结构的重要手段。为了研究不同基本苗对粳稻品种‘南粳51’产量的影响,进而为该品种的大面积推广应用提供理论依据。本研究以 ‘南粳51’为试验材料,在高产栽培条件下,研究了每穴不同栽插基本苗数下‘南粳51’产量及构成因素的变化。结果表明：株行距统一为13.3 cm×25 cm的条件下,‘南粳51’每穴4苗的实收产量最高,每穴5苗的实收产量最低,不同基本苗处理间实收产量顺序依次表现为4苗/穴＞3苗/穴＞2苗/穴＞5苗/穴。随着每穴苗数的增加,‘南粳51’的单位面积有效穗数和结实率逐渐增加,穗粒数逐渐降低,千粒重几乎没有差异。产量构成因子与产量的回归和通径分析结果说明：‘南粳51’产量的提高主要依靠穗粒数的增加。     

不同种植密度对夏玉米品种株型及产量性状的影响

为了阐述不同玉米品种株型及产量性状对密度响应,以目前生产上广泛种植的6个品种（‘郑单958’、‘先玉335’、‘伟科702’、‘浚单20’、‘金海5号’、‘利民33’）为材料,研究4个种植密度(60000、90000、112500、127500株/hm2)下不同品种株型和产量性状的变化。结果表明：6个品种棒三叶面积及茎粗系数均随着密度增加而减小,但减小幅度在不同品种或不同叶位存在差异。产量构成因素如穗长、穗粗、穗行数、行粒数、穗粒数和千粒重随着密度增加而减小。4个种植密度中,‘金海5号’、‘伟科702’、‘郑单958’在密度为90000株/hm2时产量为最高;其他3个品种随密度增加,产量降低。回归分析发现在10个已知影响玉米产量因素中,穗粒数对产量的直接影响最大,其次为行粒数。此结果为玉米品种选育和生产上高效栽培提供理论依据。     

种植密度对夏玉米品种株型及产量性状的影响

为了阐述不同玉米品种株型及产量性状对密度响应,以目前生产上广泛种植的6个品种(‘郑单958’、‘先玉335’、‘伟科702’、‘浚单20’、‘金海5号’、‘利民33’)为材料,研究4个种植密度(60000、90000、112500、127500株/hm2)下不同品种株型和产量性状的变化。结果表明:6个品种棒三叶面积及茎粗系数均随着密度增加而减小,但减小幅度在不同品种或不同叶位存在差异。产量构成因素如穗长、穗粗、穗行数、行粒数、穗粒数和千粒重随着密度增加而减小。4个种植密度中,‘金海5号’、‘伟科702’、‘郑单958’在密度为90000株/hm2时产量为最高;其他3个品种随密度增加,产量降低。回归分析发现在10个已知影响玉米产量因素中,穗粒数对产量的直接影响最大,其次为行粒数。     

不同氮素水平对杂交水稻产量性状的影响

为研究杂交水稻在不同氮素水平下的产量性状差异,以生产上大面积推广应用的4个高产优质的水稻品种(‘宜香优2115’、‘冈优188’、‘宜香优1577’、‘冈优1577’)为材料,选择不同氮素水平进行试验。结果表明:水稻的品种和氮素水平的互作共同调控水稻的产量性状,‘宜香优2115’在不同氮素水平的产量差异不显著,‘冈优188’随氮素水平提高,产量显著增加,‘宜香优1577’和‘冈优1577’在正常氮素水平产量表现最好。在不同氮素水平下各产量性状对产量影响的大小顺序为:穗着粒数穗长结实率有效穗数,穗着粒数对产量的影响最大。因此,不同水稻品种对氮素敏感程度存在显著差异,在生产上需要根据田间肥力水平选择适合的水稻品种。     

播期对不同水稻品种生长特性的影响

为优化南京地区最佳播期及最适品种,以水稻品种‘两优6326’、‘南粳44’为研究对象,对不同播期试验下水稻产量和生育期及产量构成因素进行了分析。结果表明：随着播期的推迟,水稻的生育进程也相应顺延,2种水稻全生育期均缩短;播期对‘南粳44’各产量构成因素无显著影响,而‘两优6326’有效穗数在不同播期处理间差异显著(sig=0.008,P<0.05);‘两优6326’的有效穗数、‘南粳44’的有效穗数及穗粒数sig值均小于0.05,均与产量呈显著性相关;‘两优6326’产量总体高于‘南粳44’。对2种品种适宜播期综合评价表明,该地区宜早种植籼稻‘两优6326’,及早熟晚粳品种‘南粳44’。     

杂交稻不同穗粒结构品种的增产因素分析

为探索不同穗粒结构杂交稻品种高产栽培的增产因素,以在生产上大面积推广、穗粒结构不同的杂交稻汕优63、Ⅱ优838、丰两优四号3个品种为试验材料,根据3个品种参加区试的产量构成,进行有效穗、每穗粒数、结实率、千粒重4个产量构成因素与产量的相关分析、4个产量构成因素间的相关分析、4个产量构成因素与产量的通径分析。结果表明,穗数多、每穗粒数中等的汕优63,高产栽培增产的主要因素是提高有效穗与每穗粒数,对增产的贡献率分别为37.3%和38.1%,提高结实率对增产的贡献率为24.1%;穗数中等、每穗粒数较多的Ⅱ优838,高产栽培增产的主要因素是提高有效穗,对增产的贡献率为62.2%,提高每穗粒数对增产的贡献率为26.2%;穗数较少、每穗粒数多的大穗型品种丰两优四号,高产栽培增产的主要因素是提高有效穗和每穗粒数,对增产的贡献率分别为49.2%和44.8%。可见,穗数多、每穗粒数中等的品种高产栽培的增产因素是提高有效穗与每穗粒数,同时提高结实率;穗数中等、每穗粒数较多的品种高产栽培的增产因素是提高有效穗,同时提高每穗粒数;穗数较少、每穗粒数多的大穗型品种高产栽培的增产因素是提高有效穗和每穗粒数。     

抗感稻曲病水稻品种的生殖期性状分析

为了分析稻曲病的发生与水稻品种生殖期性状的关系,选用6个不同抗性的水稻品种——‘农香21’、‘福丰优2号’、‘泸优313’、‘福两优366’、‘花2号3301’和‘浦江6号’为试验材料,在温室内分别测定了供试水稻品种生殖期的一些性状参数。结果表明,水稻品种对稻曲病的抗感性与水稻叶耳间距、孕穗期、抽穗期和防御酶（POD和SOD）活性无必然的联系,但与每穗谷粒数和穗型有一定关系。其中,抗病品种‘泸优313’的每穗谷粒数最少,为113.00粒,感病品种‘花2号3301’的每穗谷粒数最多,为242.67粒,此外,抗病品种的穗型较为松散,而感病品种的穗型较为密集。由此推测,水稻每穗谷粒数及其穗型有可能作为筛选抗病品种的指标之一。     

不同水稻品种干物质积累与产量性状的相关研究

为了探讨黑龙江省南部稻区不同水稻品种干物质积累与产量性状的相互关系,选用了该稻区不同时期主栽的6个品种为试验材料,通过田间小区对比试验进行研究,结果表明：不同水稻品种干物质积累总的趋势是前期低、后期高、中期次之;不同水稻品种抽穗前、抽穗后干物质积累量比例不同,抽穗后干物质积累量明显高于抽穗前干物质积累量;干物质积累量由高到低的品种为‘松粳9号’、‘松粳3号’、‘松粳2号’、‘松粳6号’、‘五优稻1号’、‘藤系138’;产量由高到低的品种为‘松粳9号’、‘松粳3号’、‘松粳6号’、‘松粳2号’、‘五优稻1号’、‘藤系138’;拔节至齐穗期和齐穗至成熟期干物质积累量与产量呈显著正相关;抽穗前干物质积累量与每穗粒数、千粒重呈极显著正相关;抽穗后干物质积累量与产量呈显著正相关;总干物质积累量与产量呈极显著正相关;成穗率与产量呈极显著正相关,结实率与产量呈显著正相关。合理提高拔节至成熟期干物质积累量有利于提高本稻区水稻产量。     

施肥量对2个超级稻品种叶片SPAD值的影响

为探讨超级稻品种‘松粳9 号’和‘松粳15’叶片SPAD 值的变化规律,明确叶片SPAD 值与产量性状的关系,以超级稻‘松粳9 号’和‘松粳15’为材料,通过田间小区对比试验,研究了不同肥力条件下超级稻‘松粳9 号’和‘松粳15’上部4 个叶片在拔节期、抽穗期、灌浆期、成熟期SPAD 值的变化。结果表明,随着施肥量的增加,2 个超级稻品种叶片SPAD 值呈逐步增加的趋势,施肥量越高增加的幅度越小。在整个调查期内,‘松粳15’叶片SPAD 值明显高于‘松粳9 号’。2 个超级稻品种叶片SPAD 值与每穴穗数、每穗粒数、公顷产量呈正相关,与结实率、千粒重呈负相关,与每穗粒数、结实率相关性更为紧密,相关性达到了显著或极显著水平。     

响应曲面法优化硅磷交互作用下的水稻产量

研究了硅肥、磷肥及他们的交互作用对水稻产量的影响。采用盆栽水稻技术,应用响应曲面法分析了施用不同比例的硅肥、磷肥对水稻单位面积穗数、每穗平均籽粒数、结实率和千粒重四个产量构成因素的影响。通过研究发现,磷肥能够显著影响穗均粒数和千粒重,硅肥能够显著影响桶均穗数、穗均粒数和千粒重,硅磷的交互作用亦能显著影响穗均粒数。在研究了硅肥、磷肥对水稻产量构成因素影响的基础上,通过计算获得了水稻产量与硅肥、磷肥施用量的回归模型,根据模型确定出最高产量的生产条件为：磷酸一铵1.68 g;硅酸钠5.25 g,理论产量为91.74 g。经验证实际产量为71.74 g,较空白处理提高了53.32%。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.