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1.
Maize (Zea mays L.), one of main crops in the world, is easily susceptible to Aspergillusflavus (Link: fr) infection, resulting huge loses worldwide. Breeding for A. flavus resistance has been proved an efficient way to solve the problem of aflatoxin contamination. Genetic analysis of the sources of resistance to A.flavus in maize is necessary for this purpose. The complete diallel crosses of 6 inbred lines with different resistance to A.flavus infection were implemented. Inoculation categorical data of each cross were analyzed with the additive-dominant and additive-dominant-epitasis genetic models. Results indicated some crosses fitted the 2 major genes with additive-dominant-epitasis genetic model. Others fitted the major gene and polygene mixed model. Moreover, the additive, dominant, and epitasis effects varied in crosses. The A.flavus resistance was controlled by both major gene and polygene.  相似文献   

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Cucumber powdery mildew is one of the most destructive diseases of cucumber throughout the world. In the present study, inheritance of powdery mildew resistance in three crosses, and linkage of resistance with amplified fragment length polymorphism (AFLP) markers are studied to formulate efficient strategies for breeding cultivars resistant to powdery mildew. The joint analysis of multiple generations and AFLP technique has been applied in this study. The best model is the one with two major genes, additive, dominant, and epistatic effects, plus polygenes with additive, dominant, and epistatic effects (E-l-0 model). The heritabilities of the major genes varied from 64.26% to 97.82%, and susceptibility was incompletely dominant for the two major genes in the three crosses studied. The additive effects of the two major genes and the dominant effect of the second major gene were high, and the epistatic effect of the additive-dominant between the two major genes was the highest in cross I . In cross II, the absolute value of the additive effect, dominant effect, and potential ratio of the first major gene were far higher than those of the second major gene, and the epistatic effect of the additive-additive was the highest. The genetic parameters of the two major genes in cross III were similar to those in cross II. Correlation and regression analyses showed that marker E25/M63-103 was linked to a susceptible gene controlling powdery mildew resistance. The marker could account for 19.98% of the phenotypic variation. When the marker was tested on a diverse set of 29 cucumber lines, the correlation between phenotype and genotype was not significant, which suggested cultivar specialty of gene expression or different methods of resistance to powdery mildew. The target DNA fragment was 103 bp in length, and only a small part was found to be homologous to DNA in the other species evaluated, which indicated that it was unique to the cucumber genome.  相似文献   

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Based on the genetic clustering from 42 microsatellite (SSR) markers with a combination of their geographic origin and germplasm characteristics, 124 maize landraces from Wuling Mountain region in China were used for constructing a core collection. Four evaluating parameters for maize landrace core collection, including mean difference percentage (MD), variance difference percentage (VD), coincidence rate of range (CR), and variable rate of coefficient of variation (VR), were assessed With 20 quantitative traits. It was shown that genetic relationships among landraces in Wuling Mountain region had the tendency to associate with their geographic origins. The 124 landraces were clustered into 18 subgroups when the coefficient of genetic similarity (GS) is 0.28. Eighteen landraces, each of which was from one subgroup, were applied to construct the core collection with a sampling percentage of 15%. Comparison of the initial and core collection indicated that there existed no significant differences in most quantitative traits. An average of 6.3 and 6.5 alleles were detected in the initial and core collection, respectively. Mean polymorphism information content in the core collection (0.75) was higher than that in the initial one (0.72). MD was lesser than 20% and CR was more than 80%. The results showed that the sampling strategy would be feasible for constructing the core collection that well represents the genetic diversity of the initial one.  相似文献   

5.
In China, the purity of maize hybrid strain is discomforting to the development of seed industrialization. Finding a new method for reproduction of maize hybrid strain is necessary. In this study, using particle bombardment, barstar gene was transferred into maize inbred line 18-599 (White), which is an antiviral and high quality maize inbred line. By molecular detection of the anther of transgenic maize, two plants transferred with barstar gene were gained in this study, which are two restorer lines. The two plants showed normal male spike, and lively microspores. But the capacity of the two restorer lines should be studied in the future. The aim of this study is to find a new method of reproduction of maize hybrid strain using engineering restorer lines and engineering sterility lines by gene engineering technology.  相似文献   

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In this paper the authors inquire why, after more than 25 years of domestic agricultural reforms in Mexico and 15 years of trade liberalization of maize under the North American Free Trade Agreement (NAFTA), the domestic production of maize, a non-competitive crop and the major staple in Mexico, has increased. The authors present new empirical evidence showing that, as expected, maize prices in Mexico dropped until 2006 and have experienced a process of convergence with USA prices, and maize imports from the USA have increased. However, despite lower prices, maize production in Mexico has trended upward since 1992, two years before the beginning of NAFTA's implementation. Based on the heterogeneity of maize production in Mexico, three possible explanations are proposed to explain this unexpected outcome: government supports to big commercial farmers in the agriculturally rich North of Mexico; the persistence of maize production by subsistence farmers; and to a lesser degree, increasing yields on some irrigated maize farms. We finish the paper by drawing lessons from the experience of Mexico for other Less Developed Countries.  相似文献   

8.
common maize synthetic rate( Photosynthetic characteristics were probed by sweet maize, waxy maize, high starch maize and The results revealed that leaf area index (LAI), chlorophyll a content, chlorophyll b content,photo-PR) showed single peak curve at the whole growth stage. The stages of peak were different according to different varieties. NEAUS4 had the lowest peak and while SIDAN 19 had the highest among all stages. Ratio of chlorophyll a to b was low at seedling stage, reached the peak atjointing stage and then declined. SIDAN 19 had the lower level at the last stages.  相似文献   

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Head smut of maize (Zea mays L.), which was caused by Sporisorium reiliana, occurred in most of the maize growing areas of the world. The purpose of this study was to develop SCAR markers for map-based cloning of resistance genes and MAS. Two sets of BC3 progenies, one (BC3Q) derived from the cross Qi319 (resistance)x Huangzao 4 (susceptible),the other (BC3M) from Mol 7 (resistance)x Huangzao 4 (susceptible), were generated. Huangzao 4 was the recurrent parent in both progenies. A combination of BSA (bulked segregant analysis) with AFLP (amplified fragment length polymorphism) method was applied to map the genes involving the resistance to S. Reiliana, and corresponding resistant and susceptible bulks and their parental lines were used for screening polymorphic AFLP primer pairs. One fragment of P13M61-152 was converted into SCAR (sequence charactered amplified fragment) marker S130. The marker was mapped at chromosome bin 2.09, the interval of a major QTL region previously reported to contribute to S. Reiliana resistance.Furthermore, S130 was highly associated with resistance to S. Reiliana, and could be useful for marker-assisted selection and facilitate map-based cloning of resistance genes.  相似文献   

12.
玉米抗粗缩病毒SCAR分子标记的开发   总被引:7,自引:0,他引:7       下载免费PDF全文
[目的]通过开发抗玉米粗缩病实用分子标记,实施标记辅助选择可以明显提高抗病育种效率.[方法]在对国内外152份玉米自交系粗缩病抗性鉴定的基础上,利用抗病自交系和感病自交系基因组DNA构建基因池,结合AFLP技术筛选多态扩增片段;在抗池及抗病自交系与感池及感病自交系间筛选出表现一致的多态片段转化为SCAR标记;通过152份玉米自交系粗缩病抗性鉴定验证标记与玉米粗缩病的相关性.[结果]筛选到2个与玉米粗缩病抗性显著相关的SCAR标记,即SCAR69和SCAR74.[结论]开发的SCAR(SCAR69和SCAR74)标记可应用于抗玉米粗缩病毒分子标记辅助选择.  相似文献   

13.
Mitochondrial orf355-orf77 and the nuclear fertility restorer locus Rf3/rf3 mutually control the fertility of male gametes inCMS-S in maize (Zea maya L.). A fragment of gene Zm26Sub5 was identified through cDNA-AFLP from a set of Rf3/rf3near-isogenie lines in a previous study. In the present study, real-time PCR analysis revealed that Zm26Sub5 expression levels were much higher in pollen of S-MoI7Rf3Rf3 than in pollen of S-Mo 17rf3rf3, and also higher than in fresh leaves, mature leaves, and roots of both S-Mo 17Rf3Rf3 and S-Mo 17rf3rf3. In silico cloning of full-length cDNA was successfully implemented.Gene Zm26Sub5 was 1451 bp in size, of which 1329 bp encoded a protein with 443 amino acids. The structure of this genewas analyzed by comparing its full length cDNA to homologous genomie DNA sequence (GenBank accession: Ac209463.3).Subsequent sequence analysis led to sub cellular localization of protein ZM26SUB5, and construction of a phylogenetic tree.In silico mapping indicated that Zm26Sub5 was located on chromosome 5 and closed to a reported starch-filled pollen ratio QTL. ZM26SUBS, therefore might have potential roles in repressing mitochondrial PCD which is associated with sterile activity in pollen in S-type cytoplasm.  相似文献   

14.
The genetic diversity of ten Robinia pseudoacacia L. populations collected from China was analyzed by amplified fragment length polymorphism (AFLP) technique using ten primer combinations. A total of 752 amplified bands were obtained, among which 352 (46.8%) were polymorphic. At species level, the percentage of polymorphic loci (P) was 49.87%, the Shannon’s information index (I) was 0.2160, and the mean Nei’s gene diversity index (H) was 0.1403. At population level, P = 25.47%, I = 0.1381, and H = 0.0927. The genetic diversity within populations was higher than that among populations. The coefficient of gene differentiation among populations within species (Gst) was 0.390, which indicated that gene differentiation was mainly within the population, and between populations, it accounted for 33.90% of the total variation. Gene flow (Nm) between the populations was 0.975, suggesting that the gene exchange between populations was small. The UPGMA cluster analysis showed that the ten populations were divided into three major groups, and most individuals from the same population were clustered together. There was no significant correlation between the genetic diversity parameters (D, I N , P, Ne, H, and I) and geographic and climatic factors (longitude, latitude, annual mean temperature, and annual mean precipitation). The results provide useful information about the level of genetic diversity, and it has a wide application prospect in Robinia pseudoacacia L. utilization and breeding in China.  相似文献   

15.
Molecular genetic maps of crop species can be used in a variety of ways in breeding and genomic research such as identification and mapping of genes and quantitative trait loci (QTLs) for morphological, physiological and economic traits of crop species. However, a comprehensive genetic linkage map for cultivated peanut has not yet been developed due to the extremely low frequency of DNA polymorphism in cultivated peanut. In this study, 142 recombinant inbred lines (RILs) derived from a cross between Yueyou 13 and Zhenzhuhei were used as mapping population in peanut (Arachis hypogaea L.). A total 652 pairs of genomic-SSR primer and 392 pairs of EST-SSR primer were used to detect the polymorphisms between the two parents. 141 SSR primer pairs, 127 genomic-SSR and 14 EST-SSR ones, which can be used to detect polymorphisms between the two parents, were selected to analyze the RILs population. Thus, a linkage genetic map which consists of 131 SSR loci in 20 linkage groups, with a coverage of 679 cM and an average of 6.12 cM of inter-maker distance was constructed. The putative functions of 12 EST-SSR markers located on the map were analyzed. Eleven showed homology to gene sequences deposited in GenBank. This is the first report of construction of a comprehensive genetic map with SSR markers in peanut (Arachis hypogaea L.). The map presented here will provide a genetic framework for mapping the qualitative and quantitative trait in peanut.  相似文献   

16.
S-a, S-b and S-c are three loci for F1 pollen sterility in cultivated rice (Oryza sativa L.). Taichung 65 (T65) is all Sj/Sj at these three loci, while its F1 pollen sterile near-isogenic lines, TISL2 (S-b), TISL4 (S-a) and TISL5 (S-c) is Sj/Sj according to their respective sterility locus. Using SSR molecular marker to detect the segregation of the allele Si and Sj in pollen calli population induced from different hybrid F1, which have different pollen sterility locus, showed that the segregation of allele Si and Sj was distorted. The distorted direction of pollen calli population in vitro was not the same as F2 population in vivo. The quantities of pollen callus carrying Sj were much more than that of carrying Siat S-a and S-c locus, the ratio of Si and Sj were 1:4.81 and 1:1.96 respectively. But the opposite tendency was observed at S-b locus, the ratio of Si and Sj being 1:0.35. At the same time, all these results were undisturbed by either culture medium or culture period.  相似文献   

17.
Specific activity, substrate specificity, and kinetic parameters (Km and Vmax) of glutathione S-transferases (GSTs) towards three substrates, 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), and p-nitrobenzene chloride (pNBC) were investigated in six tissues (foregut, midgut, hindgut, fat body, hemolymph, and muscle) of Oxya chinensis. In addition, the inhibition in vitro (ethacrynic acid, and Cibacron Blue 3GA) of Oxya chinensis in the six tissues was also investigated. Glutathione S-transferase activity was detected in all the six tissues examined. The rank order of GST activities towards CDNB was fat body 〉 midgut 〉 hindgut 〉 muscle 〉 foregut 〉 hemolymph both in females and males. Glutathione S-transferase activities in the fat body in females and males were 1.3- to 10.4-fold and 1.1- to 10.0- fold higher than those in the other tissues. The rank order of GST activities towards the other substrates changed slightly. From these results, it was inferred that GSTs in the fat body and midgut played important roles in detoxifying xenobiotics including insecticides and plant allelochemicals in O. chinensis. In the three substrates examined, CDNB seemed to be the best substrate, followed by pNBC and DCNB. The kinetic parameters of GSTs were different among the six tissues. This suggested that GSTs in different tissues have various affinities and catalytic efficiency to substrates. In vitro inhibition study showed that the median inhibition concentration (IC50) values of the two inhibitors to GSTs from the six tissues were different. The results suggested that the two inhibitors have different inhibition potency to GSTs from the different tissues. The observed changes in kinetic parameters and inhibition in vitro among the six tissues of the insect might suggest that the number and structure of isoenzymes and their rate of expression varied for the different tissues.  相似文献   

18.
Soybean cyst nematode (SCN Heterodera glycines Ichinohe) is one of the most important nationwide soybean diseases in China. A total of 38 soil specimens or locations in the area was sampled and tested for SCN races during 2001-2003 for the inspection of race distribution in Huang-Huai Valleys. A map of race distribution was constructed according to the data from both the present study and the published reports cited. Three areas, namely, the area of southeast to Jinan in Shangdong Province; the area of northern Henan Province and its border region to south of Hebei Province; and the area of Luohe, Zhoukou of Henan Province and Fuyang of Anhui Province mainly infested with Race 1 were identified. Race 4 was predominant in Shanxi Province, Beijing and the adjacent area of Henan, Shandong, and Anhui provinces, and the delta of Huanghe River in Shandong Province. Race 2 was mainly found in Liaocheng, Dezhou of Shangdong Province and Shijiazhuang of Hebei Province, and Jiaozuo and Huojia of Henan Province. Race 7 was distributed in the west part of Jiaodong Peninsula of Shandong Province and Kaifeng, Huaxian, Wenxian of Henan Province. Race 5 was found and scattered in Hebei and Henan Province. Race 9 was found in Shangqiu of Henan Province, which was reported for the first time in China. It can be seen that Race 1 and Race 4 were the two predominant races in Huang-Huai Valleys, and that research should focus on developing resistant cultivars of these races. There might exist other races in an area with some predominant races. The race substitution in the past decade was not obviously found, therefore, the results should be meaningful to future breeding for resistance to SCN in Huang-Huai Valleys.  相似文献   

19.
To study insecticidal mechanism of terpinen-4-ol, a main insecticidal composition in the essential oil of Sabina vulgaris, the 5th instar larvae of Mythimna separta, were investigated with terpinen-4-ol by topical application. The activities of phosphatase, glutathione S-transferase (GSTs), cytochrome P450 (P450), and polyphenol oxidase (PPO) of tested insects were determined in all poisoning stages, including exciting stage, convulsing stage, paralysis stage, and recover stage. The result showed that the activities of both acid phosphatase (ACP) and alkaline phosphatase (AKP) in treated insects were induced by terpinen-4-ol, but ACP was inhibited in paralysis stage. The activities of GSTs were inhibited in exciting stage, convulsing stage, and paralysis stage, but gradually recovered in recover stage. O-demethylase activity of cytochrome P450 was inhibited by terpinen-4-ol, and the inhibition rate in all poisoning stages were 26.27, 46.03, 80.24, and 90.22%, respectively. PPO activities were strongly inhibited by terpinen-4-ol both in vitro and in vivo. In conclusion, the activities of P450, GSTs, and PPO could have relation with toxicity of terpinen-4-ol against larvae of the Mythimna separta, but recover stage of the poisoning insects might be related to GSTs induced. As a new insecticide or synergist, terpinen- 4-ol has a potential value in field of insecticide resistance management.  相似文献   

20.
The experiment was carried out to study the genotypic difference in the responses of seed germination, growth and physiological characters of rice seedlings to Cd toxicity. The result showed that the germination was slightly stimulated under low Cd concentration (0.01-1.5 mM Cd), while severely depressed under higher Cd concentration (2.0 mM). Rice seedlings exposed to 0.01 mM Cd showed slight increases in plant height, root volume, biomass and chlorophyll concentration. These parameters were significantly reduced when Cd level in the medium was increased to 0.5 mM, and meanwhile corresponding increase in superoxide dismutase (SOD) and peroxidase (POD) activities, and MDA (malondialdehyde) content was observed. However, SOD and POD activities declined when plants were exposed to 1 mM Cd when compared with those under 0.5 mM Cd. Cadmium addition lowered Fe, Cu and Mn concentrations in roots and shoots. There was significant genotypic difference in the response of these parameters to Cd stress. Under Cd stress, Xiushui 110 had the least inhibition of growth and increase in MDA content, higher shoot Cd concentration, and greatest increase in POD and SOD activities, indicating its higher tolerance to Cd toxicity, while Bing 9914 had the greatest reduction of growth, and Zn, Cu, Fe, and Mn contents, but greatest increase in MDA content, and least increase in activities of antioxidative enzymes, indicating its sensitivity to Cd toxicity.  相似文献   

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