玉米‘洛玉863’群体动态指标研究

‘洛玉863’是洛阳农林科学院选育而成的高淀粉型玉米新品种,为了对该品种的高产栽培和示范推广提供理论依据,通过采用田间定点定株取样和公式法,研究了品种的群体动态指标,以明晰其适宜群体产量结构和群体动态指标,为品种的高产栽培和示范推广提供理论依据。结果表明：‘洛玉863’适宜种植密度为60000株/hm2,产量结构为60000穗/hm2、穗行数15.0行、行粒数37.5粒、千粒重381.5 g,群体生产力得到了充分的发挥,产量达12599.4 kg/hm2。适宜密度下,群体各项动态指标发展协调,叶面积指数(LAI)在吐丝期最大值达到5.41,且稳定期长,成熟时仍达2.94,使‘洛玉863’活秆成熟的优点得到充分体现;叶面积持续期(LAD)总量达到335.46×104 m2?d/hm2,在各生育时期的分配合理;净同化率(NAR)与叶面积持续期(LAD)协调较好;干物质积累总量24702.3 kg/hm2,其中吐丝期以后的干物质积累量占全部积累量的60%;群体生长率(CGR)达247.0 kg/(hm2?d);灌浆速率始终保持在合理的较高水平。吐丝期以后的叶面积指数(LAI)、叶面积持续期(LAD)、干物质积累量和群体生长率(CGR)与最终的籽粒产量呈密切的正相关,可以作为适宜群体的标志。     

不同种植密度对超高产稻田春玉米产量性状及光合生理特性的影响

通过不同种植密度对“紧凑型”品种超试1号的群体光合生理性能及产量性状进行研究.结果表明,在6.75 ～ 9.75万株/hm2密度范围内,随着种植密度的增加,群体叶面积指数(LAI)显著增大,光合势(LAD)增加,冠层的光合有效辐射(PAR)的截获率增大,但叶片叶绿素相对含量(SPAD)降低和比叶重(SLW)下降;在灌浆...     

内蒙古河套灌区强筋小麦优质高产栽培技术研究

采用基本苗(X1)、种肥N(X2)、种肥P2O5(X3)、种肥K2O(X4)、一次追N(X5)、最高茎数(X6)、二次追N(X7)、根外肥时间(X8)、根外尿素(X9)、根外磷酸二氢钾(X10)10个因素,分前后两段两个5因素正交旋转组合设计.其中X6既作为前段试验的结果,又为后段试验的处理因素.通过田间试验和品质分析,得到了9个因素和产量、粗蛋白含量的组合数学模型.经计算机优化分析,最终提出了内蒙古河套灌区产量在6000 kg/hm2以上,蛋白质含量＞14.5%的高产优质综合栽培技术方案基本苗446.0～447.4万株/hm2,种肥N 30.8～30.9 kg/hm2,第一次追N125.8～126.3 kg/hm2,第二次追N 62.8～63.0 kg/hm2,根外肥为6月22日喷施,喷施尿素4611～4632 g/hm2,喷施KH2PO44591～4612 g/hm2.     

水稻超高产栽培专家系统应用研究

通过总结遵义市农业科技人员和农民群众长期积累的水稻高产栽培经验和1999-2000年实施“水稻百万亩高产栽培技术应用与研究”项目水稻超高产栽培经验,研制了“遵义市水稻超高产栽培专家系统计算机软件”,并用以指导大田超高产栽培示范,同时进行试验研究,不断完善系统。采用小区试验与大面积验证相结合的方法,研究了“水稻超高产栽培专家系统”计算的栽插密度、施肥量、肥料施用时期指导栽培对产量、产量构成、肥料利用率的影响,以及中迟熟大穗型组合超高产的质量指标。结果表明以冈优、Ⅱ优系列为主,搭配优质稻组合,两年13.98hm2平均产量达到741.3kg/667m2,其中2001年最高产田块达856.5kg/667 m2。小区试验专家系统指导栽培产量达843.4kg/667m2.比经验栽培增产7.6％。达极显著水平;有效穗16.625万/667 m2、穗实粒数178.4粒、千粒重29g;化肥N,P2O5,K2O利用率分别达到32.6％,24.0％,45.9％;叶面积动态前期表现增长快,中期平稳,后期不早衰,最大叶面积期是始穗期,叶面积指数6.42,齐穗期功能叶叶面积3278.1m2/667m2,比重大,占总叶面积的82.6％;单株干物质日增重以幼穗分化-始穗,齐穗-灌浆、灌浆-成熟3个阶段增长最快,分别为1.14g/d,1.18g/d,0.85g/d;全生育期平均净同化率为4.13g/m2·d;成熟期干物质积累量132     

黔中喀斯特山区抗旱耐瘠玉米品种冠层结构和光合势研究

采用二因素随机区组试验设计,对适应黔中山区农业生态条件的不同类型抗旱耐瘠杂交玉米品种的植物学表型特征、叶面积指数、冠层透光率、光合势、经济性状、产量等生理、生产指标变化趋势进行了研究。结果表明：披叶大穗型品种（顺单7号）和披叶中穗型品种（安单3号）在中低密度（4.5万株/hm2）处理时各项冠层结构指标、光合性能指标、经济性状指标较优,源丰库足流畅,产量高,分别为10085.55 kg/ hm2和10277.4 kg/hm2;半紧凑中穗型品种（顺单6号）,在高密度（5.25-6.0万株/hm2）处理时各项指标较优,源丰库足流畅,产量高,为12072.75kg/hm2。结果显示,不同类型玉米品种在适宜的种植密度下,群体冠层结构较合理,光合势较强,吐丝后的群体LAD较高,后期光合面积持续时间较长, 有利于玉米产量的提高。     

施氮量对滴灌冬小麦光合特性、产量及氮素利用效率的影响

在田间研究了5 种施氮量N0 (0 kg/hm2)、N1 (90 kg/hm2)、N2 (180 kg/hm2)、N3 (270 kg/hm2)、N4(360 kg/hm2)处理对‘新冬18 号'旗叶光合特性、干物质积累、产量及氮素利用效率的影响。结果表明：拔节期增加施氮量,增加孕穗期旗叶的叶绿素和可溶性蛋白质含量、光合速率、叶面积指数、春季总光合势。孕穗期施氮肥延缓旗叶叶绿素和可溶性蛋白含量、光合速率、叶面积指数的衰减;孕穗后均以N3、N4的旗叶叶绿素和可溶性蛋白质含量、光合速率、叶面积指数、春季总光合势较高,干物质积累量和产量也以N3、N4较高。随施氮量的增加干物质积累量和产量增加,氮肥利用效率降低。在本试验条件下增加施氮量使旗叶叶绿素和可溶性蛋白含量、光合速率、叶面积指数增加及其功能期的延长是‘新冬18号’增产的主要原因。综合考虑施氮量在180~270 kg/hm2范围内,氮肥农学利用效率为6.9 kg/kg,可满足‘新冬18号’产量为8004.85 kg/hm2的需要。     

不同施氮水平对滴灌冬小麦干物质生产及产量的影响

为探明北疆滴灌冬小麦高产栽培适宜的施氮量。大田滴灌条件下,设置0 kg/hm2 (N0)、104 kg/hm2(N1)、173 kg/hm2 (N2)和242 kg/hm2 (N3)4 个施氮水平,研究施氮量对滴灌冬小麦叶面积指数(LAI)、干物质积累、分配、转运及产量和氮肥利用效率的影响。结果表明：冬小麦LAI 于灌浆期前呈N3＞N2＞N1＞N0,之后为N2＞N3＞N1＞N0;各处理单株干物重变化均为快增、缓增、略降,N2处理干物质积累最大速率出现时间(t0)较N1、N3处理提前1.42 天和2.75 天,干物质最大增长速率(Vm)增加了21.74%和12.00%,且N2处理向籽粒干物质分配显著高于N1、N3处理(P＜0.05);产量以N2处理最高,为8455.69 kg/hm2,较N0、N1、N3处理分别高出32.82%、12.64%、5.16%;氮肥农学利用效率(NAE)和氮肥偏生产力(NPP)随着施氮量的增多而降低,N1处理较N2、N3处理NAE提高了16.64%和110.08%,NPP提高了37.58%和128.02%。综合分析,建议北疆滴灌冬小麦灌水定额为3750 m3/hm2时,适宜施氮量应控制在104~173 kg/hm2之间。     

不同种植密度下的夏玉米冠层结构及光合特性

研究了种植密度对夏播玉米(CF008、郑单958和金海5号）冠层结构及光合特性的影响,目的是通过密度调控,构建高效冠层,发挥品种潜力,同时确立不同夏玉米品种高产高效冠层的定量化技术指标。结果表明,3个夏玉米品种均在中或低密度下（CF008为9.75和11.25万株 hm-2,郑单958为8.25和9.75万株 hm^-2,金海5号为6.75和8.25万株 hm^-2）构建的冠层较合理,冠层光合性能较高。冠层内透光率、叶夹角、茎粗、叶绿素相对含量（SPAD值）和净光合速率（Pn）均随着密度的增加而降低,说明高密度易造成群体内光分布不合理,导致光合性能的降低。灌浆中期前群体光合势（LAD）和叶面积指数（LAI）均表现为中或高密度条件下较高,而后为中或低密度下较高,并且吐丝后LAD所占比率为中或低密度处理显著高于高密度处理,说明高密度条件下冠层结构不合理,造成生育后期叶片提早衰老。在中或低密度下,群体穗位层透光率较大,吐丝期和灌浆中期分别为13.4%~19.45%和16.19%~21.48%;叶面积发展动态较为合理,吐丝期LAI达5.59~6.75,成熟期仍然保持在2.24~3.68,尤其中上层叶片LAI高值持续期较长;吐丝期中上层叶片Pn达到33.6~43.8 μmol CO2 m^-2 s^-1;吐丝后的群体LAD较高,特别是中密度下LAD达172.01~235.91 m2 d m-2,后期光合面积持续时间较长,更有利于玉米产量的提高。     

氮素用量及施肥方法对菜豌豆根瘤量和产量的影响

针对玉溪市菜豌豆生产上存在过量施肥和施肥方法不当的问题,采用田间试验方法开展研究,结果表明,N素不同用量、种肥施用N肥比例和磷肥比例的大小或施与不施均对菜豌豆根瘤干重和豆荚产量有明显影响;菜豌豆种肥不宜施用氮肥,而磷肥可作种肥施用;以N 600~750 kg/hm2、P2O5 60 kg/hm2、K2O 75 kg/hm2的施肥结构,并采用种肥不施N肥、追肥12~15次、磷肥50%~100%作种肥施用的施肥技术,小荚豆和甜脆荚豆的菜豌豆产量最高。     

行距配置和种植密度对薏苡光合生理、籽粒灌浆及产量的影响

为薏苡高产栽培提供参考依据,采用2 因素裂区设计,设置2 种行距（等行距、宽窄行）和4 种密度（7 万、6 万、5 万、4 万株/hm2）,研究不同的种植方式对薏苡花后光合生理、籽粒灌浆及产量的影响。结果表明：宽窄行种植改善了薏苡的群体结构,提高了叶片光合性能和籽粒灌浆能力,与等行距种植的薏苡相比,4 种密度种植的薏苡产量分别提高7.87%、7.90%、7.87%和8.75%;种植密度对薏苡产量影响显著,2 种行距配置的薏苡都以种植密度为5 万株/hm2时产量最高,分别达到4544.1、4901.9 kg/hm2。薏苡的适宜种植密度为5万株/hm2,宽窄行种植是薏苡高产栽培的有效措施。     

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.     

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.     

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.     

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.