Extent, variation and breeding impact of natural cross-fertilization in German winter faba beans using hilum colour as marker     

Seif Gasim  Stefan Abel  Wolfgang Link 《Euphytica》2004,136(2):193-200

Faba bean is a partially allogamous grain legume, mostly sown as spring crop in Central Europe, and in few mild coastal areas of UK and France as a winter crop. A population with a genetically wide base, conceived and selected for superior winter hardiness showing promise as winter crop in Germany was evaluated. The reproductive behaviour of this population was evaluated for its degree of cross-fertilization at five German environments (1999–2001), and inbred lines bred from it, plus one F1 bulk and further checks, were assessed for variation in cross-fertilization at three German environments (2001). Seed hilum colour, a dominant-recessive, biallelic locus, was used as a morphological marker. Cross-fertilization (population mean value of 60%) was shown to be higher than in spring faba beans and was environmentally influenced. Genetic variation was demonstrated, heritability was high (h²= 0.75), and heterosis was negative. Inbred lines with a cross-fertilization of 70% can be easily bred. Breeding synthetic cultivars is recommended, their optimum number of components is expected to be higher than the optimum recommended for spring faba beans. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Development of synthetic Brassica napus lines for the analysis of “fixed heterosis” in allopolyploid plants     

S. Abel  C. Möllers  H. C. Becker 《Euphytica》2005,146(1-2):157-163

Summary Allopolyploids are widely spread in the plant kingdom. Their success might be explained by positive interactions between homoeologous genes on their different genomes, similar to the positive interactions between different alleles of one gene causing heterosis in heterozygous diploid genotypes. In allopolyploids, such interactions can also occur in homozygous genotypes, and may therefore be called “fixed heterosis”. As to our knowledge, no experimental data are available to support this hypothesis. We propose an experimental approach to quantify “fixed heterosis” in resynthesised Brassica napus and the detection of loci contributing to “fixed heterosis” via comparative QTL mapping in B. napus and its parental species B. rapa and B. oleracea. In order to develop a genetically balanced material, interspecific crosses between 21 Brassica rapa and 16 Brassica oleracea doubled haploid or inbred lines were performed. In total 3485 vital embryos have been obtained from 9514 pollinated buds. The success of interspecific hybridisation was highly depending on the maternal genotype (B. rapa) and ranged from 0 to 1.18 embryos per pollinated bud. For the genetic characterisation of the B. rapa and B. oleracea lines, a dendrogram was constructed based on 273 RAPD markers. Thus a well-characterised material is now available, which is suitable to analyse the effects of “fixed heterosis” and the interactions between homoeologous genes in allopolyploid species.  相似文献   

Sero-molecular survey and risk factors of equine piroplasmosis in horses in Spain     

Eliazar Camino  Aranzazu Buendia  Abel Dorrego  Pilar Pozo  Lucía de Juan  Lucas Dominguez  Fatima Cruz-Lopez 《Equine veterinary journal》2021,53(4):771-779

  相似文献   

Precision, repeatability and representative ability of faecal egg counts in Heterakis gallinarum infected chickens     

Daş G  Savaş T  Kaufmann F  Idris A  Abel H  Gauly M 《Veterinary parasitology》2011,183(1-2):87-94

This study investigated whether a precise and repeatable quantification of Heterakis gallinarum egg excretion, which considerably reflects the actual worm burdens, can be achieved based on collection of the daily total amount of faeces from chickens. Three-week-old birds (N=64) were infected with 200 embryonated eggs of H. gallinarum, and placed into individual cages 3 wk after infection for 5 wk to collect daily faeces (N=2240). The total daily faeces was mixed and a randomly taken sample per bird was analyzed to estimate the numbers of eggs per gram of faeces (EPG) and total number of eggs excreted within 24h (EPD). A total of 235 daily faecal collections were randomly selected and further examined to determine between and within sample variations of EPG counts as a measure of precision. For this, two random faecal samples were taken from the daily produced faeces by a bird, and the EPG was determined for each of the samples (EPG1 and EPG2). The second faecal sample was analyzed once more to determine a parallel EPG2 count (EPG2a) of the suspended sample. Precision of an EPG count was defined as its relative closeness to the average of two EPG counts using a relative asymmetry index (Index(EPG)). At an age of 11 wk, i.e. 8 wk p.i. the birds were slaughtered and their worm burdens were determined. There were no significant differences between EPG1 and EPG2 (P=0.764) nor between EPG2 and EPG2a (P=0.700), suggesting that the differences between or within the samples were not different from zero. Correlations between EPG counts, as between and within sample coherences, were r=0.85 and r=0.86, respectively. Precision of EPG counts, as measured by Index(EPG), was not influenced by consistency (P=0.870) and total amount of faeces (P=0.088). However, concentration of eggs in faeces (mean EPG) had a significant effect on the precision of the EPG counts (P<0.001). Similar results were also observed for the within sample precision (Index(EPG2)). A segmented regression analysis indicated an abrupt change in the precision of EPG counts as the response to changing egg concentration in the examined faecal samples. The precision of analyses remarkably heightened up to a breakpoint with an EPG count of ≤ 617. A similar breakpoint was also determined for within sample precision (EPG2 ≤ 621). Moderate repeatabilities (R=0.49) for EPG and EPD were estimated in the first week of egg excretion, whereas the estimates were higher (R=0.67-0.84) in the following weeks. Correlations between number of female worms with daily measured EPG and EPD increased to an almost constant level (r ≥ 0.70; P<0.05) in a few days after the nematode excreted eggs and predominantly remained so for the rest of the sampling period. It is concluded that mixing daily total faeces provides samples with random homogenous distribution of H. gallinarum eggs. Precision of the EPG counts increases as the egg concentration in faecal sample increases. Egg excretion of H. gallinarum, quantified either as EPG or EPD, is highly repeatable and closely correlated with the actual worm burden of birds starting as early as in 5 th wk of infection.  相似文献   

Effect of climate factors on conception rate of lactating dairy cows in Mexico   总被引：1，自引：1，他引：0  

Villa-Mancera A  Méndez-Mendoza M  Huerta-Crispín R  Vázquez-Flores F  Córdova-Izquierdo A 《Tropical animal health and production》2011,43(3):597-601

The purpose of this study was to investigate the relationship between conception rate (CR) and climate variables. Data consisted of 24,380 inseminations of Holstein dairy herd in Hidalgo, Mexico. Weather records, including daily temperature (T), relative humidity (RH), rainfall, wind speed, and solar radiation, were obtained from a nearby weather station. Means for each climatic variable from 2 days before artificial insemination (AI) to the AI day were calculated for each conception date represented in the study. A significant negative correlation was observed between the CR and mean and minimum T, mean and minimum RH, mean and minimum temperature–humidity index (THI), and rainfall. The overall mean CR was 34.3%. The CR in lactating dairy cows followed a seasonal pattern, lower CRs were observed in summer months than during winter (32.1% vs. 36.9%; P < 0.01). The variables that had the greatest influence on CR were minimum and maximum T, minimum RH, minimum THI, wind speed, and rainfall.  相似文献   

A New High-Pressure Form of Sulfur Derived from the Decomposition of S4N4     

Vezzoli GC  Abel J 《Science (New York, N.Y.)》1978,200(4343):765-766

A new phase of sulfur is formed from S(4)N(4) held at pressure-temperature conditions in the vicinity of the boundary representing the decomposition of S(4)N(4) to fibrous sulfur, S(x). The new phase is gray-black, is persistently metastable at room conditions, and is insoluble in carbon disulfide. The phase is apparently formed from a stage of decomposition during which high-conductance transients are observed in in situ electrical experiments. The sulfur phase appears to form upon the release of the nitrogen from a sulfur-nitrogen chain that is produced from the scission of an S(4)N(4) ring.  相似文献   

Merogony in in vitro cultures of Theileria parva     

Madder M  Speybroeck N  Berkvens D  Baudoux V  Marcotty T  Pita Bah I  Geysen D  Brandt J 《Veterinary parasitology》2003,114(3):195-203

In vitro studies were focussed on the duration and cessation of merogony in Theileria parva infected blood lymphocyte cell cultures. The cultures were infected using purified tick stabilates as an alternative to in vitro infections, using sporozoites obtained by labour intensive dissections of salivary glands from infected ticks. After establishment of infection in peripheral blood lymphocytes (PBL), merozoites were temporarily produced for about 2 months after which lymphoblasts only contained schizonts.  相似文献   

A Prediction Model Framework for Cyber-Attacks to Precision Agriculture Technologies     

Abel Duarte Alonso 《Journal Of Agricultural & Food Information》2013,14(4):307-321

This study examines farmer-consumer interactions from the perspective of 30 Alabama farmers that are predominantly selling their produce directly to consumers via farmers’ markets, on-site sales, and roadside markets. The findings demonstrate that respondents are actively engaged in educating consumers in several ways; for instance, providing recommendations and food tastings, while those growers that are involved in agritourism are—whether consciously or unconsciously—also educating visitors about the farm and its produce. Clearly, the importance of direct sales may be a compelling argument for farmers to be involved in educational activities. However, given the current emphasis that government, consumer groups, and consumers themselves are placing on healthier diets and the social aspect of local food consumption, the future implications for food growers with regard to consumer education may extend beyond the sales aspect.  相似文献   

Food Animals and Veterinary Medicine     

Abel Duarte Alonso 《Journal Of Agricultural & Food Information》2013,14(1):75-90

While there appear to be very clear associations between food growers, the hospitality sector, and educational institutions offering hospitality management or related degrees, to date very few studies discuss those links. In particular, little is known of food growers’ perceptions of educational institutions, also in regard to how those institutions could assist farmers. This study seeks to add knowledge to those unresearched areas, learning from a group of 30 Alabama farmers. The findings clearly demonstrate that educational institutions offering hospitality degrees can play several positive roles in assisting farmers, such as in raising awareness about the “local” element of foods or even involving students in various constructive ways. Several implications are discussed concerning the findings and future research avenues are suggested.  相似文献   

The use of spearfishing competition data in fisheries management: evidence for a hidden near collapse of a coastal fish community of Galicia (NE Atlantic Ocean)     

P. Pita  J. Freire 《Fisheries Management and Ecology》2014,21(6):454-469

The use of commercial catch statistics to estimate overfishing consequences has been criticised, but alternative long‐term data sets are rare. Long time‐series data sets from recreational fisheries competitions have been used to infer trends in coastal fish communities. Here an historic archive (1953–2007) of recreational spear fisheries in Galicia (NW Spain) was employed to estimate long‐term changes in coastal ecosystems. Using generalised additive regression models, decreases in the abundances of coastal rocky reef fishes of up to 76% over the last 50 years were found. In the same period, the mean body weight also decreased by 76%. In addition, relative catch frequency has decreased for the most valuable commercial species. Overfishing, amongst other human impacts, has brought these ecosystems so close to collapse that it is urgent to implement measures to ensure their recovery.  相似文献