Diallel analysis among 16 maize populations adapted to the northern U.S. Corn Belt for grain yield and grain quality traits     

Tonette P. Laude  Marcelo J. Carena 《Euphytica》2014,200(1):29-44

Genetically diverse germplasm is needed to increase frequency of favorable alleles of economically important traits in maize improvement. The objectives of this study were to determine the genetic components involved in grain yield and grain quality traits, and provide preliminary assessment of useful heterotic groups and patterns from a large sample of maize populations adapted to the northern U.S. Corn Belt. Sixteen populations were used in the diallel mating design following Gardner–Eberhart Analysis II to estimate variety (v _i ) and heterosis (h _ij ) genetic effects for grain yield and grain quality traits. Specific heterosis (s _ij ) and predicted means of population crosses for grain yield were used to evaluate the heterotic relationships among the populations. Data for grain yield and grain quality traits were generated in partially balanced single lattice experiments across North Dakota (ND) locations in 2010, 2011, and 2012. Analyses of variance showed significant differences among genotypes. Heterosis effects explained most of the differences among diallel entries for grain yield, while v _i effects had greater influence on grain quality traits. NDL, EARLYGEM 21c, NDSCD(FS-CS)C2, NDSS, and NDSM(M-FS)C9 were identified as elite populations for grain quality improvement. NDSS × NDBS22(R-T1)C9 and NDBS1011 × EARLYGEM 21c showed high s _ij effects for grain yield with good grain quality. NDSS and EARLYGEM 21c represent stiff stalk synthetic (SSS) group, and NDBS1011 fall under non-SSS group. Further studies need to validate the heterotic group of NDBS22(R-T1)C9. Recurrent and pedigree selection programs will be established for selected populations and population crosses to integrate pre-breeding with cultivar development.  相似文献   

Effects of habitat degradation on the abundance, richness and diversity of raptors across Neotropical biomes     

Martina Carrete  Jos L. Tella  Guillermo Blanco  Marcelo Bertellotti 《Biological conservation》2009,142(10):2002-2011

Population growth and human development result in biodiversity loss and biological homogenization not only in developed countries, but increasingly in the less developed countries as well. In those countries, where urbanization and agricultural intensification occur at a faster rate than in developed countries, habitat degradation appears to be the leading cause of wildlife loss. During the breeding seasons of 2002–2005 we conducted road surveys across five biomes of Argentina to detect variations in raptor community attributes as potential indicators of broad scale habitat degradation. Abundance of individuals, richness and diversity of species were calculated to assess the effects of habitat transformation and patch size on these community attributes. Raptor communities strongly varied in relation to habitat transformations, with lower abundance of individuals, richness and diversity of species in more transformed landscapes. Small patches of natural vegetation and locations in which natural and cultivated lands where interspersed showed lower richness and diversity of raptors than large patches. Fragmentation was the main cause of reductions in abundance of individuals. Although the relative contribution of our two estimates of habitat degradation to abundance, richness and diversity of raptors varied among biomes, these community attributes proved useful as predictors of habitat degradation. This was especially true in habitats where raptor communities are more complex although overall patterns remained constant across biomes, from forests to deserts. Taking into account current trends of habitat transformation (drastic increments in monocultures, urban areas, and habitat patchiness), the conservation of raptor communities in these biomes could be seriously compromised. In terms of species-specific responses of raptors to habitat degradation, a rapid process of homogenization can be expected, resulting in only a few winner species within a general scenario of losers.  相似文献   

Nitrogen uptake by sago palm (Metroxylon sagu Rottb.) in the early growth stages     

Suzette B. LINA  Masanori OKAZAKI  Dorothea Sonoko KIMURA  Yoshiharu YANO  Koyo YONEBAYASHI  Masato IGURA  Marcelo A. QUEVEDO  Alan B. LORETO 《Soil Science and Plant Nutrition》2009,55(1):114-123

Previous trials have revealed variable responses of sago palm ( Metroxylon sagu Rottb.) to fertilizer application, particularly nitrogen (N). In the present study, we quantified the fertilizer use efficiency (FUE) of sago palm for the first time using ¹⁵N-labeled fertilizer in pot and field experiments. The pot experiment was conducted in Japan using a 2:1 mixture of sand to Philippine soil. The field experiment was conducted in Leyte in the Philippines. Both experiments consisted of three replicates in each of three treatments: control, ¹⁵N urea at 50 kg N ha⁻¹ and ¹⁵N urea at 100 kg N ha⁻¹. The N uptake of sago palm increased significantly, but inconsistently with increasing N application. The few instances of a significant increase in N uptake did not translate into significant improvements in growth parameters, except for the number of leaflets in the pot experiment. The FUE values for sago seedlings (< 6 months) in the pot experiment treated with 50 and 100 kg N ha⁻¹ were 10.5 and 13.2%, respectively, whereas for the 2-year-old sago palms in the field, the corresponding FUE values were 14.8 and 12.0%. The FUE values were similar at the two levels of N application in both experiments. Sago growth parameters appeared to be insensitive to N application, suggesting that the form of N and the timing of N fertilization are important factors for sago palms. Therefore, the use of N fertilizer in sago production can only be justified after determining and fully understanding the response of sago palm to N application.  相似文献   

Relationship Between Soft Wheat Flour Physicochemical Composition and Cookie‐Making Performance     

Malena Moiraghi  Leonardo Vanzetti  Carlos Bainotti  Marcelo Helguera  Alberto Len  Gabriela Prez 《Cereal Chemistry》2011,88(2):130-136

Nowadays in Argentina, cookies, crackers, and cakes are made of flour obtained from bread wheat with additives or enzymes that decrease the gluten strength but increase production costs. The present research work aims to study the relationship between flour physicochemical composition (particle size average [PSA], protein, damaged starch [DS], water soluble pentosans [WSP], total pentosans [TP], and gluten), alkaline water retention capacities behavior, solvent retention capacities profile (SRC) and cookie‐making performance in a set of 51 adapted soft wheat lines with diverse origin to identify better flour parameters for predicting cookie quality. Cookie factor (CF) values were 5.06–7.56. High and significant negative correlations between sucrose SRC (–0.68), water SRC (–0.65), carbonate SRC (–0.59), and CF were found, followed by lactic SRC that presented a low negative but significant correlation (r = –0.35). The flour components DS (r = –0.67), WSP (r = –0.49), and TP (r = –0.4) were negatively associated to CF. PSA showed a negative correlation with CF (r = –0.43). Protein and gluten were the flour components that affected cookie hardness, but no significant correlation were found with pentosan or DS content. A prediction equation for CF was developed. Sucrose SRC, PSA, and DS could be used to predict 68% of the variation in cookie diameter. The cluster analysis was conducted to assess differences in flour quality parameters among genotypes based on CF. Clusters 1 and 4 were typified by lower CF (5.70 and 5.23, respectively), higher DS, pentosan content, and SRC values. Cluster 2 with a relative good CF (6.47) and Cluster 3 with the best cookie quality, high CF (7.32) and low firmness, and the lowest DS, TP, WSP content, and sucrose SRC values.  相似文献   

Different isolates from Leishmania braziliensis complex induce distinct histopathological features in a murine model of infection     

Cristiano G. Pereira  Alexandre L.N. Silva  Patrícia de Castilhos  Eneida C. Mastrantonio  Richard A. Souza  Raquel P. Romo  Renata J. Rezende  Janethe D.O. Pena  Marcelo E. Beletti  Maria A. Souza 《Veterinary parasitology》2009,165(3-4):231-240

The aim of this study was to evaluate the histopathological features in tissues of mice infected by human isolates (I, II, and III) or the reference M2903 strain of Leishmania braziliensis complex. BALB/c and C57Bl/6 mice were infected in the hind footpad with 10⁶ stationary-phase promastigotes of L. braziliensis complex. The evolution of lesions was observed for 10 weeks and the animals were then euthanized and liver, spleen and popliteal lymph nodes were collected. Tissues were stained with hematoxylin and eosin and analyzed by immunohistochemistry assay. Increased thickness of infected footpads was observed in all animals, lesions were nodular and non-ulcerated. Mice infected with isolate I presented inflammatory infiltrates consisting predominantly of mononuclear cells in all tissues examined, and also a great number of megakaryocytes, compared with other isolates. Infection with isolate II led to an infected footpad enlargement not seen in other isolates. In addition, mononuclear infiltrates in the liver and hemosiderin in spleen were noted. Conversely, mice infected with either isolate III or M2903 strain only showed an increased number of megakaryocytes in spleen. All tissues examined had detectable amastigote forms of Leishmania by immunohistochemistry in all groups. Taking together, our results showed an unforeseen behavior of different isolates of L. braziliensis complex that led to diverse pathological findings.  相似文献   

Serotype distribution and production of muramidase-released protein, extracellular factor and suilysin by field strains of Streptococcus suis isolated in the United States     

Nahuel Fittipaldi  Troy E. Fuller  Janet F. Teel  Thomas L. Wilson  Thaddeus J. Wolfram  David E. Lowery  Marcelo Gottschalk   《Veterinary microbiology》2009,139(3-4):310-317

Streptococcus suis is an important swine pathogen and a zoonotic agent. Differences in virulence have been noted among the 33 described serotypes, serotype 2 being considered the most virulent. In this study, we aimed at assessing the serotype distribution and the production of virulence-associated markers by strains recovered from diseased pigs in the United States (U.S.). Results showed that among the 100 strains evaluated, serotype 3 (20% of the isolates) and serotype 2 (17%) were the most prevalent. We then investigated the presence in these isolates of the genes sly, epf and mrp, encoding the virulence-associated markers suilysin (SLY), extracellular factor (EF) and muramidase-released (MRP) protein, respectively. The effective production of the markers by the strains was also verified. Results showed that the presence of the gene did not always correlate with actual expression of the respective protein. In the case of MRP, this was due, in most cases, to frameshift mutations at the 5′ end of the gene resulting in premature stop codons. The most prevalent phenotypes among U.S. strains were MRP⁺EF⁻SLY⁻ (40%) and MRP⁻EF⁻SLY⁺ (35%). Serotype distribution greatly differed from that reported in several European countries, as did the production of virulence markers, particularly for serotype 2. On the other hand, our results for the U.S. S. suis isolates are similar to those reported for Canadian strains, suggesting a common status in North America.  相似文献   

Prevalence of Rickettsia species antibodies and Rickettsia species DNA in the blood of cats with and without fever     

Bayliss DB  Morris AK  Horta MC  Labruna MB  Radecki SV  Hawley JR  Brewer MM  Lappin MR 《Journal of Feline Medicine and Surgery》2009,11(4):266-270

Rickettsia species antibodies have been detected in some cats but it is unknown whether infected cats develop clinical signs. The prevalence of Rickettsia species deoxyribonucleic acid (DNA) in blood from clinically ill cats has not been determined. The objective of this study was to determine if cats with fever (body temperature >or=102.5 degrees F [39.2 degrees C]) were more likely to have evidence of rickettsial infection than healthy, age-matched, control cats with a body temperature<102.5 degrees F. Rickettsia species polymerase chain reaction (PCR) assays were performed to detect rickettsial DNA extracted from blood (71 paired samples), indirect immunofluorescence assays (IFA) were performed to detect serum antibodies against Rickettsia felis (90 paired samples) and Rickettsia rickettsii (91 paired samples), and the results between pairs were compared. All samples were negative for Rickettsia species DNA. More cats with fever were seropositive for R felis or R rickettsii than control cats, but results were not statistically significant. Results of this pilot study failed to show an association between Rickettsia species DNA or Rickettsia species antibodies and fever.  相似文献   

The horizontal barrier effect of stems on the foraging behaviour of cattle grazing five tropical grasses     

Marcelo A. Benvenutti  Iain J. Gordon  Dennis P. Poppi  Robert Crowther  Warwick Spinks  Fabiana C. Moreno   《Livestock Science》2009,126(1-3):229-238

The rate of nutrient intake (RNI) is a primary determinant of animal performance in grazing cattle and depends on both diet quality and instantaneous intake rate (IIR). In turn, diet quality and IIR are a function of the foraging behaviour of the animal (selectivity, bite mass and bite rate) and the characteristics of the sward. In this study we evaluated the effect of the stem density and the tensile resistance of stems on the foraging behaviour of cattle grazing tropical pasture species. The methodology involved the use of small sown microswards offered to tethered cattle. The experiment consisted of a factorial combination of five tropical grasses [Bothriochloa pertusa (Bp), Chloris barbata (Cb), Chloris gayana (Cg), Cynodon dactylon (Cd) and Heteropogon contortus (Hc)] and three stem densities (0, 400 and 800 stems m^− 2). Bp and Cd had stems of significantly lower tensile resistance (19 and 15 N respectively) (Group 1) than those of Cb, Cg and Hc (110, 211 and 167 N respectively) (Group 2). The steers avoided stems of Group 2 and thus, reduced bite area, bite mass, IIR and RNI as stem density increased. However, the animals did not avoid stems of Group 1 and there was no effect of stem density on any of the foraging behaviour variables when cattle grazed species in Group 1. These results confirm that RNI and plant part selection is closely associated with the tensile resistance of the stem.  相似文献   

Investigation of Neospora sp. and Toxoplasma gondii antibodies in mares and in precolostral foals from Parana State, Southern Brazil     

Locatelli-Dittrich R  Dittrich JR  Richartz RR  Gasino Joineau ME  Antunes J  Pinckney RD  Deconto I  Hoffmann DC  Thomaz-Soccol V 《Veterinary parasitology》2006,136(3-4):215-221

Infections with Eimeria parasites can lead to severe diarrhoea with considerable clinical and economic consequences in first-year grazing stock. To identify and characterise the cause of diarrhoea observed during previous years, 164 animals on 14 dairy farms in northwestern Germany were included in this study. The calves were physically and parasitologically examined prior to turnout and until 21 days post turnout (d.p.t.). Mean animal weights decreased from 194.9 kg at the start to 189.3 kg bodyweight at the end of the study. In all herds, oocyst counts were very low prior to turnout and increased after the calves had been kept on pasture for at least 7 days. On Day 9 post turnout, 90% and at the end of the study (21 d.p.t.) 70% of all animals showed Eimeria-positive faecal samples. During the course of the study, 79 (48.2%) animals passed faecal samples with more than 100,000 oocysts per gram. The predominant species identified was Eimeria alabamensis, which accounted for more than 83% of the oocysts counted. These parasitological findings matched the clinical observations. Diarrhoea was found in 130 (79.3%) of the study animals. At 5d.p.t. and thus prior to the rise of faecal oocyst counts, a significant increase in diarrhoea was recorded. Calves showing diarrhoea excreted statistically significantly more often over 100,000 E. alabamensis oocysts per gram faeces (0.28; p = 0.0002) than calves without diarrhoea. Diarrhoea was also found during significantly more study days in animals with high oocyst counts (0.39; p = 0.0001). These data indicate that in endemic areas first-year grazing calves must be considered at risk to develop clinical coccidiosis due to E. alabamensis infection during the first 2-3 weeks post turnout.  相似文献   

Medium Light and Medium Roast Paper-Filtered Coffee Increased Antioxidant Capacity in Healthy Volunteers: Results of a Randomized Trial   总被引：1，自引：1，他引：0  

TA Corrêa  MP Monteiro  TM Mendes  DM Oliveira  MM Rogero  CI Benites  CG Vinagre  BM Mioto  D Tarasoutchi  VL Tuda  LA César  EA Torres 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(3):277-282

We compared the effects of medium light roast (MLR) and medium roast (MR) paper-filtered coffee on antioxidant capacity and lipid peroxidation in healthy volunteers. In a randomized crossover study, 20 volunteers consumed 482?±?61?ml/day of MLR or MR for four weeks. Plasma total antioxidant status (TAS), oxygen radical absorbance capacity (ORAC), oxidized LDL and 8-epi-prostaglandin F2α, erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activity were measured at baseline and after the interventions. MLR had higher chlorogenic acids-(CGA; 334?mg/150?mL) and less caffeine (231?mg/150?ml) than MR had (210 and 244?mg/150?ml, respectively). MLR also had fewer Maillard reaction products (MRP) than MR had. Compared with baseline, subjects had an increase of 21 and 26?% in TAS, 13 and 13?% in CAT, 52 and 75?% in SOD, and 62 and 49?% in GPx after MLR and MR consumption (P?相似文献