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71.
Barley yellow mosaic disease is caused by several viruses, i.e. barley yellow mosaic virus (BaYMV), barley mild mosaic virus (BaMMV) and BaYMV-2. The reaction of different barley germplasms to the barley mosaic viruses was studied in field and greenhouse experiments. The results show a complex situation; some varieties are resistant to all the viruses, while others are resistant to one or two of them only. Crosses between different barley germplasms were earned out in order to test whether genetic diversity of resistance against mosaic viruses does exist, particularly, BaMMV. A total of 45 foreign barley varieties were crossed to German cultivars carrying the resistance gene ym4. In F2 of 27 crosses, no segregation could be detected, leading to the conclusion that the resistance genes of the foreign parents are allelic with ym4 e.g. Ym1 (‘Mokusekko 3’) and Ym2 (‘Mihori Hadaka 3’). A total of 18 crosses segregated in F2 indicating that foreign parents, like ‘Chikurin Ibaraki 1’, ‘Iwate Omugi 1’, and “Anson Barley”, carry resistance genes different from the gene of German cultivars, e.g. ‘Asorbia’ or ‘Franka’. By means of statistical evaluation (Chi2-test), the observed segregation ratios were analyzed in order to obtain significant information on the heredity of resistance. All the resistance genes described here as being different from the gene ym4, act recessively. Most of the exotic varieties seem to carry only one resistance gene. In a few cases, more than one gene may be present. 相似文献
72.
The methods of equivalent linearization of different energy dissipation devices are different in analyzing passive energy dissipation structure including different type of energy dissipation device by using of mode-superposition response spectrum method based on equivalent linearization, which results in the differences in computing accuracy and cost in dynamic analysis. For structures separately installed different energy dissipation devices, authors utilize relatively uncoupled mode-superposition method and complex mode-superposition method for contrast analysis, and probe into the suitability of the two methods in the dynamic analysis of passive energy dissipation structure. Numerical results show that complex mode-superposition method could be better for structure with viscous dampers in order to guarantee accuracy, and relatively uncoupled mode-superposition method is recommended for structure with viscoelastic, metallic or frictional ones. 相似文献
73.
A simple procedure for yield component analysis 总被引:3,自引:0,他引:3
H. -P. Piepho 《Euphytica》1995,84(1):43-48
Summary This paper introduces a simple method of analysing yield components. It allows quantification of the contribution of each component to the variability of final yield. The method is based on log-transforms of measurements of the component traits. Applications in heterosis breeding and stability analysis are discussed. The method is compared to other procedures of yield component analysis. 相似文献
74.
75.
杨爱民 《中国水土保持科学》2005,3(1):93-96
在分析、总结食物链理论的基础上,首次提出了基于社会经济自然复合生态系统的泛生态系统、泛生态元、泛生态链和泛生态网的概念,并对泛生态链的类型划分进行了探讨。泛生态链理论是对食物链理论的拓展和创新,能够科学地解释和描述复合生态系统中各泛生态元之间的相互关系。 相似文献
76.
Genetic variation and relationships among members of the azuki bean complex (Vigna angularis) including wild (V. angularis var. nipponensis), weedy, and cultivated types (V. angularis var. angularis), V. nakashimae, and rice bean (V. umbellata) from Korea were examined using the Amplified fragment length polymorphism (AFLP) method. AFLP analysis of 50 accessions
revealed 333 (72.1%) polymorphic fragments out of 462 fragments amplified using seven primer combinations. The number of polymorphic
fragments within each species was 70 in the azuki bean complex and 41 in V. nakashimae, but there was no polymorphism in rice bean. The number of shared fragments among species ranges from 142 between the azuki
bean complex and V. nakashimae to 166 between the azuki bean complex and rice bean. Within the azuki bean complex, the range of shared bands was from 231
between cultivated and weedy types to 238 between cultivated and wild types. A dendrogram generated from Jaccard’s similarity
matrix was divided into three groups, which correspond to V. nakashimae, azuki bean complex, and rice bean. The relationship between azuki bean and rice bean is closer than between azuki bean and
V. nakashimae. Phenetic distances averaged 0.502 between the azuki bean complex and V. nakashimae and 0.467 between the azuki bean complex and rice bean. Within the azuki bean complex, the weedy type was more closely related
to wild than cultivated types. But UPGMA dendrogram of the azuki bean complex reveals that each type is not clearly isolated.
These results will help to understand genetic diversity and evolutionary dynamics of Vigna in Korea. 相似文献
77.
Tianyun Wu Jeff J. Schoenau Fengmin Li Peiyuan Qian Sukhdev S. Malhi Yuanchun Shi 《植物养料与土壤学杂志》2005,168(1):100-107
The influence of fertilization on organic‐carbon fractions separated by density and particle size in Heilu soil (Calcic Kastanozems, FAO) was investigated in a 20‐year (1979–1999) long‐term experiment on the Loess Plateau of China. Compared to an unfertilized treatment, N application alone did not increase total organic carbon (TOC) and its fractions of density and particle size. However, the treatment of N + P fertilization significantly increased salty‐solution–soluble organic carbon (SSOC), microbial biomass C (MB‐C), and organic C associated with fine silt. When manure was applied alone and in combination with N and P fertilizer, the light fraction of organic C (LFOC), SSOC, and MB‐C were increased significantly, and the TOC was as high as that of a native Heilu soil. Organic C associated with different particle‐size fractions was also increased significantly, and the allocation of C among the fractions was altered: the proportions of C in sand (>50 μm), coarse‐silt (20–50 μm), and fine‐clay (<0.2 μm) fractions were increased whereas fine‐silt (2–20 μm) and coarse‐clay (0.2–2 μm) fractions were decreased. It is concluded that N fertilizer alone is not capable of restoring organic‐matter content in the Heilu soils of the Loess Plateau and that C‐containing material like manure and straw is necessary to produce significant increase in soil organic carbon in these soils. 相似文献
78.
Enzymatic activity (EA) was explored as a possible tool for composting characterization. Three composts (yard wastes, cotton wastes and a mixture of the two) were sampled during different phases of the process and divided in two fractions. The first was immediately analysed for microbial biomass C (BC) and EAs (β-glucosidase, arylsulphatase, acid and alkaline phosphatase). The second fraction was air-dried prior to analysis for the same EAs and for organic C (CORG), total N (NTOT), dissolved organic C (DOC), extractable C (CE) and humic-like C (CH).BC decreased throughout the composting period (149 days), whereas EA in moist fractions stabilized between 50 (β-glucosidase, alkaline phosphatase) and 90 (arylsulphatase, acid phosphatase) days of composting.EA was always reduced by air‐drying (β-glucosidase: 40-80%; arylsulphatase: 10-50%; acid phosphatase: 10-70%; alkaline phosphatase: 50-90%), but this effect was less prominent as composting proceeded, especially for β-glucosidase and alkaline phosphatase.EA in air-dried samples displayed the same trend as in moist ones, except that there was a marked difference (47-66%) between initial and final activities of all four enzymes.EAs in air‐dried compost and content of humic-like substances showed a similar trend: a marked increase in the first 90 days of the process and no significant variations afterwards. This suggests that the formation of humic-enzymatic complexes has taken place and indicates that this process occurs almost totally during the first stage of composting.EA steadiness in air-dried samples occurred concurrently with the achievement of compost stability, as indicated by the conventional indexes (i.e. CH, CORG/NTOT). Therefore, the development of a stable enzyme activity in air-dried compost could represent a simple measure of compost stabilization in routine analysis of composting process. 相似文献
79.
[目的]分析新疆维吾尔自治区呼图壁河径流变化特征与长期变化趋势,为制定科学合理的呼图壁地区水资源供需平衡发展战略提供理论支撑。[方法]采用变差系数法、距平累积法、Mann-Kendall非参数秩次相关检验法及Morlet连续复小波变换对呼图壁河石门水文站1978—2011年实测日流量资料进行分析。[结果]呼图壁河径流的年内变化主要受降水与气温的影响,其主要径流产生于5—9月,汛期为6—8月,径流量占全年径流量的69.4%,枯水期为12月至次年3月。呼图壁河的Cv平均值为0.149。近34a来径流量整体呈现出不显著的增加趋势,径流量的年际变化小,年际间持续枯水与持续丰水的时间几乎相同。此外,呼图壁河年径流存在4个较为显著的周期波动,其中18和29a分别为径流量年际变化的第Ⅰ、第Ⅱ主周期。[结论]呼图壁河近34a来径流量呈增加趋势,径流量的年际变化呈现出较为显著的周期性,径流量的年内分配很不均匀。 相似文献
80.
以鹅肉为原料制成鹅肉香肠,确定了以植物乳杆菌、戊糖片球菌、木糖葡萄球菌为复合菌种的最佳条件,并在单因素试验的基础上选择了菌种配比、接种量、发酵温度和时间4个因素进行正交试验。结果表明,制作鹅肉香肠的最佳的条件为:发酵时间为24h,接种量1.5%,发酵温度为30℃。 相似文献