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1.
In perspective of breeding high-yield hybrid pepper varieties, combining ability analysis of net photosynthesis rate at different phases of flowering and fruit setting in pepper was made with 15 cross combinations from 6 parents by (1/2) n (n- 1) diallel crosses. There are relatively large differences not only in general combining ability (GCA) effect among different parents and at different phases of flowering and fruit setting, but also in specific combining ability (SCA) effect among different hybrids. There are relatively large GCA effects in late parents but relatively less GCA effects in early parents. No obvious laws have been found in the relationship between SCA effects and maturity of hybrids. Variances of SCA are larger than those of GCA. Heritability is less but influence of environment is larger. Correlation analysis of combining ability between net photosynthesis rate and agronomic character or resistances to main diseases has showed that correlation coefficients of GCA are relatively large at the medium phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and fruit characters. Correlation coefficients of SCA are relatively large at the early phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and plant characters at the early phase but to plant characters and fruit characters at the late phase. Correlation coefficients of SCA between net photosynthesis rate and resistances to main diseases are larger than those of GCA. The combining abilities of net photosynthesis rate at different phases of flowering and fruit setting are positively correlated with those of yield per plant. The combining ability is an important parameter of breeding of high photosynthesis hybrid pepper varieties.  相似文献   

2.
Research Status Quo and Future of Low Temperature Wheat Genotypes   总被引:1,自引:1,他引:1  
Low temperature wheat genotypes are a group of wheat with a slightly low canopy (plant) temperature, and the research on their biological characters and utilization in wheat breeding has been done at home and abroad for more than 20 years, and has made great progress. The research contents and advances include the following respects: Wheat genotypes with slightly low canopy temperature have been verified to exist in nature; these wheat genotypes, which present cold temperature, are superior to conventional wheat materials in some important biological characters and particularly prominently in metabolic function and cellular structure; when they suffer stresses such as drought, high temperature and overcast and rainy weather, they still retain their superiority in some of their important biological characters and therefore have a wide range of ecological adaptability; slightly low canopy temperatures of these genotypes are closely correlated with low temperatures of their second heat sources and their vigorous plants; since their low canopy temperatures can be inherited, they can exert favorable influence on the temperatures of their offspring while crossing with other wheat materials, and in particular, the discovery of cold-source wheat as a contributor to low temperature, has further formed good conditions for breeding high and stable quality low temperature wheat varieties with a high and stable yield. Thus, low temperature wheat genotypes are of great research importance and have great prospects.  相似文献   

3.
Bemisia tabaci (Gennadius) is a species complex, which includes different geographical populations with genetic differentiation. The recent progress on the genetic differentiation of various geographical populations of B. tabaci complex was introduced. The genetic differentiation was further analyzed on the basis of the sequences of mtDNA COI and rDNA ITS1 recorded in the world's GenBank. Five groups are defined on the basis of mtDNA COI and rDNA ITS1, including the Asia group, America group, Africa group, Australia group, and Biotype B/Mediterranean/Middle East/ Northern Africa/Biotype Ms group. There are several ungrouped geographical classifications, such as the Uganda population, Ivory Coast population, and Taiwan population. Geographical isolation may be the most important factor that contributed to the genetic differentiation of various geographical populations of B. tabaci. Many populations with biological advantages invaded new regions and caused severe economic losses within human activity. It is necessary to strengthen the research of B. tabaci biotype to prevent the spread of invaded populations and the invasion of potentially dangerous populations.  相似文献   

4.
两个有限超可解群的积   总被引:1,自引:0,他引:1  
讨论了有限群G是两个有限群A,B之积时的超可解性的问题.利用半正规和拟正规的概念,在较弱的条件下给出了群G超可解的一些充分条件.
Abstract:
The supersoluability of a finite group G when it is the product G of two finite supersoluable groups A and B is discussed. Some sufficient conditions of the supersoluability of G are obtained under some weaker hypotheses by using the concept of semi-normality and quasi-normality which generalize the known.  相似文献   

5.
Citrus tristeza virus (CTV) exists in citrus as a large number of distinct strains differing in biological characters. The control strategies such as mild strains cross protection (MSCP) require a clear understanding of the characterization of CTV. For better understanding of the structure of CTV population and the relationship between molecular and biological characterization, 72 CTV samples collected from five provinces in China were studied, using biological indexing, p25/Hinf I restriction fragment length polymorphism (RFLP), multiple molecular markers, and bidirectional RT-PCR assay. The mixture of severe stem pitting isolates was found to be dominant in the field. CTV isolates with p25/Hinf Ⅰ RFLP group 3 and p23/BD-PCR group Ⅰ, Ⅲ were the main cause of epidemics, and most CTV isolates were found to be the mixture of T30 and VT genotypes. More accurate identification of strain mixtures in the field and better understanding of the biological traits of the isolates may be achieved by applying the three molecular detection methods simultaneously.  相似文献   

6.
主要利用θ*-偶来研究群G的结构,得到了有限群可解和超可解的一些新的描述.
Abstract:
The purpose of this paper is to investigate the structure of a finite group G by using the concept of the θ*-pair.Some new characterizations of a finite group being solvable or super-solvable are obtained.  相似文献   

7.
在三维二次混沌系统的基础上增加一个含控制信号的状态变量,组成一个新的非自治超混沌四维二次系统.该系统的基本动力学特性的变化主要依赖于控制信号频率的改变.通过系统的Lyapunov指数谱、分岔图及数值仿真表明,在不同的频率参数下,该系统能够体现周期、拟周期、混沌、超混沌的动力学特性.最后设计了一个模拟电路,进一步验证了其特性.
Abstract:
Based on the three-dimensional quadratic chaos system, this paper constructs a new four-dimensional quadratic non-autonomous hyperchaos system by adding a state variable with the controlling signal.The change in the basic dynamics characters of this system is mainly realized by varying the frequency of the controlling signal. The different chaos dynamics characters of this system such as periodicity, quasi periodicity, chaos and hyperchaos at different frequencies is shown by Lyapunov spectrum , bifurcation diagram and numerical simulation. The results of the experiment are further shown to be consistent with the numerical simulation by designing an analog electronic circuit.  相似文献   

8.
Stunt nematodes(Tylenchorhynchus spp.) are obligate migratory root ecto-parasitic nematodes found in the fields of many cultivated crops. These nematodes, with phyto-sanitary potential, are frequently ignored or misdiagnosed as pests, and this may pose a threat to food security. The accuracy of its identification based on a morphological approach has been challenged recently, due to the overlapping of the morphological and morphometric characters of the species. Consequently, the objective of th...  相似文献   

9.
The experiment was conducted with the objective of studies on effects of zinc toxicity on lymphoid organs by the methods of experimental pathology and flow cytometry (FCM). 200 one-day-old Avian broilers were divided into four groups randomly, and fed on diets as follows: controls (Zn 100mg kg^-1)and zinc toxic (Zn 1 500 mg kg^-1, zinc toxic group Ⅰ; Zn 2000 mg kg^-1, zinc toxic group Ⅱ; Zn 2 500 mg kg^-1, zinc toxic group Ⅲ) for seven weeks. The weight and growth index of the thymus, spleen and bursa of Fabricius were reduced in both zinc toxic group Ⅱ and zinc toxic group Ⅲ when compared with those of control group. The G0/G1 phase of the cell cycles of the lymphoid organs was higher, and S, G2 M phases lower in zinc toxic groups Ⅱ and Ⅲ than in control group. Lymphocytes were depleted and degenerate in the lymphoid organs. The reticular cells of the bursa of Fabricius proliferated and the reticular cells of the thymus were also degenerate and necrotic,particularly in zinc toxic groups Ⅱ and Ⅲ. The results demonstrated that more than 1500 mg kg^-1 impaired the progression of lymphocytes from the G0/G1 phase to S phase obviously, inhibited the development of lymphoid organs and caused marked pathological changes in the lymphoid organs. Potential mechanisms underlying these observations are also discussed.  相似文献   

10.
Inflammation in pulp tissue is caused by caries bacteria. Most bacteria found are Lactobacillus acidophilus. Propolis is a sticky resin material that is derived from the bees and the surrounding plants, which are reported to have several biological effects including anti-bacterial and anti-inflammatory. This study will prove the effectiveness of propolis against proinflammatory cytokines on odontoblast-like cells in human dental pulp. This study was performed on cultured odontoblast-like cells in pulp. Cell culture was derived from the pulp tissue of human M3 teeth that had been extracted. Odontoblast pulp culture was divided in three groups: group one, cultured cells with propolis; group two, cultured cells induced with inactive Lactobacillus acidophilus; group three, cultured cells induced with inactive Lactobacillus acidophilus and exposed to 3 μg/mL propolis. A measurement of TNF-α and TGF-β1 expression was done using the immunocytochemical technique to determine the effectiveness of propolis extracts from East Java Indonesia against proinfalmmatory cytokines. Data were analyzed using the analysis of variance (ANOVA) test (P = 0.05). Propolis extract can inhibit the expression of TNF-α and increase the expression of TGF-β1 on odontoblast-like cell in human dental pulp. Anti-inflammatory effects of East Java propolis extract are associated with cytokine modulation.  相似文献   

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