Identification of quantitative trait locus and prediction of candidate genes for grain mineral concentration in maize across multiple environments     

Huaduo Zhang  Jingxian Liu  Tiantian Jin  Yaqun Huang  Jingtang Chen  Liying Zhu  Yongfeng Zhao  Jinjie Guo 《Euphytica》2017,213(4):90

Trace metal elements are essential in daily diets for human health and normal growth. Maize is staple food for people in many countries. However, maize has low mineral concentration which makes it difficult to meet human requirements for micronutrients. The objective of this study was to identify quantitative trait locus (QTL) and predict candidate genes associated with mineral concentration in maize grain. Here, a recombinant inbred line population was used to test phenotype of zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn) concentrations in six environments and then a QTL analysis was conducted using single environment analysis along with multiple environment trial (MET) analysis. These two strategies detected a total of 64 and 67 QTLs for target traits, respectively. Single environment analysis revealed 13 QTL bins distributed on seven chromosomes. We found that five candidate genes associated with mineral concentration were located in the same intervals identified by Comparative mapping of meta-QTLs in our previous study. The genetic and phenotypic correlation coefficients were depended on the nutrient traits and they were significant between Fe and Zn, Fe and Cu, Fe and Mn in all environments. The results of this study illustrated the genetic correlation between maize grain mineral concentrations, and identified some promising genomic regions and candidate genes for further studies on the biofortification of mineral concentration in maize grain.  相似文献   

Estimating gene action,combining ability and heterosis for grain yield and agronomic traits in extra-early maturing yellow maize single-crosses under three agro-ecologies of Ghana     

G. A. Owusu  D. Nyadanu  K. Obeng-Antwi  R. Adu Amoah  F. C. Danso  S. Amissah 《Euphytica》2017,213(12):287

Maize (Zea mays L.) is the most important cereal crop produced in Ghana. However, yield of the crop is generally low, producing just about 1.7 t/ha. The low yield is attributed to continuous use of local/unimproved varieties. Generally, hybrid varieties have proven to out-yield the local/unimproved varieties due to improved vigour. Development of hybrid varieties depend on good understanding of combining ability and inheritance of important quantitative traits such as grain yield (GY). 45 half-diallel crosses generated from 10 extra-early maturing yellow inbred lines were evaluated in 2015 under rain-fed conditions. The objectives were to determine the genetic control, breeding value and estimate heritability for GY and agronomic traits of the inbred lines under contrasting growing environments in Ghana. General combining ability (GCA) and specific combining ability (SCA) were important in the inheritance of GY and agronomic traits of the inbred lines. However, GCA was more important than SCA across environments to suggest that additive gene action was more important than non-additive gene action in the inheritance of GY and agronomic traits in the inbred lines. High broad-sense heritability, for GY and other agronomic traits indicated preponderance of additive gene action in trait expression, thus, selection based on phenotypic expression could be feasible. Inbred lines P1, P4 and P8 were good combiners for high GY. The genotype, P4 × P8, was identified as the ideal and most yielding single-cross hybrid across research environments and should be further tested on-farm before commercialization.  相似文献   

Improved genetic parameter estimations in zoysiagrass by implementing post hoc blocking     

Lin Xing  Salvador Gezan  Kevin Kenworthy  J. Bryan Unruh  Patricio Munoz 《Euphytica》2017,213(8):195

Randomized complete block (RCB) design is the most widely used experimental design in biological sciences. As number of treatments increases, the block size become larger and it looses the capacity to control the variance within block, which is its original purpose. A method known as post hoc blocking could be used in these cases to improve the genetic parameter estimation and thus obtain an unbiased assessment of the performance of a given treatment. In trufgrass breeding, as other breeding program, this is a common challenge. The goal of this study was to test the capacity of different post hoc blocking designs to improve the genetic parameter estimation of zoysiagrass (Zoysia spp.). We evaluated two post hoc blocking designs; row–column (R–C) and incomplete block (IB) designs on five genotype trials located in Florida. The results showed that post hoc R–C design had superior model fitting than both the original RCB and the post hoc IB designs when studied at the single measurement level and at the site level. The narrow-sense heritability (0.24–0.40) and the genotype-by-measurement correlation (0.57–0.99) did not change significantly when R–C was compared to the original RCB design. The ranking of the top performing genotypes changed considerably when comparing RCB to R–C design, but the degree depended on the location analyzed. We conclude that the change in the ranking of the top (potentially select individuals) is coming from the better control of intra-block environmental variation, and this could potentially have a significant impact on the breeding selection process.  相似文献   

Reaction of <Emphasis Type="Italic">Phaseolus</Emphasis> spp. genotypes to ashy stem blight caused by <Emphasis Type="Italic">Macrophomina phaseolina</Emphasis>     

Diego M. Viteri  Angela M. Linares 《Euphytica》2017,213(8):199

Ashy stem blight (ASB) caused by Macrophomina phaseolina (Tassi) Goidanich (Mp) is a devastating seed-transmitted disease in common bean in the tropics. The identification of resistant cultivars throughout the cropping season contributes to disease management. Resistance is found in the primary and tertiary gene pools. Our objectives were to determine (1) the reaction of Phaseolus spp. genotypes to two Mp isolates at vegetative and reproductive stages, (2) the area under disease progress curve (AUDPC), and (3) resistant plants per genotype at harvest. Twenty-three genotypes from different origins were planted in the greenhouse in 2016 and 2017. One less-aggressive Mp (PRJD16) and one more-aggressive (PRI16) isolate were inoculated one and three times, respectively, by the cut-stem method. ‘Beníquez’, ‘Othello’, and ‘Verano’ were highly susceptible (mean scores >8.0, and AUDPC values from 264.6 to 300.8) to both isolates. BAT 477 and NY6020-4 were intermediate (5.6 and 6.2; AUDPC: 161.6 and 187.1) to PRJD16 and susceptible (7.4 and 8.2; AUDPC: 209.4 and 235.1) to PRI16. Resistant genotypes (mean scores ≤3) were not identified in this study. However, A 195, ‘Badillo’, and ‘PC 50’ possessed lower mean scores (4.3–5.4) and AUDPC values (126.4–150.9) to both isolates. Furthermore, A 195 had the highest percentage of resistant plants (55.6%) followed by PC 50, I9365-31, and PI 321637 (27.8%) to PRJD16 at harvest. Thus, the identification of resistant parents across Phaseolus species is necessary to increase the levels of ASB resistance in common bean cultivars throughout the entire cropping season.  相似文献   

Use of genomic and phenotypic selection in lines for prediction of testcrosses in maize II: grain yield and plant traits     

Gustavo Vitti Môro  Mateus Figueiredo Santos  Cláudio Lopes de SouzaJr. 《Euphytica》2017,213(6):128

Plant breeders have been trying to predict the performance of hybrids based on their parental performance. One application of molecular markers is its use in selection. The objectives were to map quantitative trait loci (QTL) and verify its congruence in maize lines and in their testcrosses and verify the possibility to select testcrosses from the predicted means of the lines by using information from markers. Two-hundred and fifty six lines and the testcrosses of these lines with two testers were evaluated in six environments, considering grain yield, plant lodging, days to anthesis and silking, anthesis-silking interval, plant and ear height and ear placement. QTL were mapped in the lines and in testcrosses and the predicted means of the lines were computed based on QTL effects and in all markers of the genome. The congruence of QTL detected in the lines and testcrosses were small for all traits. The correlations between the predicted means of the lines and the phenotypic means of the testcrosses ranged from low for grain yield to moderate for cycle and stature traits. The highest coincidences of the lines and selected testcrosses were observed for cycle and stature traits and the lowest for grain yield. Even by using molecular markers information, it is only possible to predict the testcrosses performance from the lines information to less complex traits and with reduced dominance effect. For complex traits and with pronounced dominance effect, information of markers must be obtained directly in the testcrosses, so they can be used for selection.  相似文献   

G.M. Turchini,W.-K. Ng and D.R. Tocher (eds): Fish oil replacement and alternative lipid sources in aquaculture feeds     

Malcolm Jobling 《Aquaculture International》2011,19(3):595-596

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Characterizing long-term forest disturbance history and its drivers in the Ning-Zhen Mountains,Jiangsu Province of eastern China using yearly Landsat observations (1987–2011)     

Mingshi Li  Chengquan Huang  Wenjuan Shen  Xinyu Ren  Yingying Lv  Jingrui Wang  Zhiliang Zhu 《林业研究》2016,27(6):1329-1341

Forest losses or gains have long been recognized as critical processes modulating the carbon flux between the biosphere and the atmosphere. Timely, accurate and spatially explicit information on forest disturbance and recovery history is required for assessing the effectiveness of existing forest management. The major objectives of our research focused on testing the mapping efficacy of the vegetation change tracker (VCT) model over a forested area in China. We used a new version of VCT algorithm built upon the Landsat time series stacks (LTSS). The LTSS consisted of yearly image acquisitions to map forest disturbance history from 1987 to 2011 over the Ning-Zhen Mountains, Jiangsu Province of east China. The LTSS consisted of TM and ETM+ scenes with different projections due to distinct data sources (Beijing remote sensing ground station and the USGS EROS Center). The validation results of the disturbance year maps showed that most spatial agreement measures ranged from 70 to 86 %, comparable with the VCT accuracies reported for many places in USA. Very low accuracies were identified in 1995 (38.3 %) and 1992 (56.2 %) in the current analysis. These resulted from the insensitivity of the VCT algorithm to detect low intensity disturbances and also from the mis-registration errors of the image pairs. Major forest disturbance types existing in our study area were identified as agricultural expansion (39.8 %), urbanization (24.9 %), forest management practice (19.3 %), and mining (12.8 %). In general, there was a gradual decreasing trend in forest cover throughout this region, caused principally by China’s economic, demographic, environmental and political policies and decisions, as well as some weather events. While VCT has largely been used to assess long term changes and trends in the USA, it has great potential for assessing landscape level change elsewhere throughout the world.  相似文献   

Effect of ammonia and nitrite on vigour,survival rate,moulting rate of the blue swimming crab <Emphasis Type="Italic">Portunus pelagicus</Emphasis> zoea     

Yong Yang Liao  Hong Hu Wang  Zhi Gan Lin 《Aquaculture International》2011,19(2):339-350

The effects of ammonia and nitrite on vigour, survival rate, moulting rate of zoea of blue swimming crab, Portunus pelagicus, were studied. A total of five nitrite-N treatments (26.67, 53.34, 106.68, 213.36, 426.72 mg/l) and a control (no nitrite-N added) were set up for the acute nitrite-N toxicity experiment; a total of five ammonia-N treatments (8.43, 16.86, 33.72, 67.44, 134.88 mg/l) and a control (no ammonia-N added) were set up for the acute ammonia-N toxicity experiment. The results showed that the vigour, survival rate and moulting rate of zoea of the blue swimming crabs exposed to over 53.34 mg/l were significantly different (P < 0.05) from the control group. The zoea LC₅₀ values (mg/l) of nitrite-N were 179.47, 76.56, 66.70, 37.49, 25.01, 25.35, 25.34 mg/l for 24, 36, 48, 60, 72, 84, 96 h, respectively. The vigour, survival rate and moulting rate of zoea of the blue swimming crabs exposed to over 16.86 mg/l were significantly different (P < 0.05) from the control group. The zoea LC₅₀ values (mg/l) of ammonia-N were 51.04, 39.62, 38.72, 24.43, 16.90, 13.42, 11.16 mg/l for 24, 36, 48, 60, 72, 84, 96 h, respectively. The zoeae are highly sensitive to ammonia and nitrite, and the toxicity of ammonia and nitrite on Portunus pelagicus decrease with development of this crab.  相似文献   

Sarkis J. Khoury: Conversations with the Conscience     

Roger Chao 《Agriculture and Human Values》2010,27(2):251-252

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Canine fetal echocardiography: correlations for the analysis of cardiac dimensions     

Amália Turner Giannico  Elaine Mayumi Ueno Gil  Daniela Aparecida Ayres Garcia  Marlos Gonçalves Sousa  Tilde Rodrigues Froes 《Veterinary research communications》2016,40(1):11-19

The aim of this study was to develop regression models for correlation of canine fetal heart development with body size to characterize normal development or suggest cardiac anomalies. Twenty clinically healthy pregnant bitches, either brachycephalic and non-brachycephalic, were examined ultrasonographically. Transabdominal fetal echocardiography was conducted every 4 days from the beginning of cardiac chambers differentiation until parturition. Ten cardiac parameters were measured: length, width and diameter of the heart; heart area; left and right ventricular dimensions; left and right atrial dimensions; and aortic and pulmonary artery diameter. Femoral length, biparietal diameter and abdominal cross-sectional area were also recorded. Regression equations were developed for each parameter of fetal body size, and linear and logarithmic models were compared. The model with the highest correlation coefficient was chosen to produce equations to calculate relative dimensions based on the correlations. Only the left-ventricular chamber differed between the two racial groups. Biparietal diameter was the independent parameter that produced the highest correlation coefficient for the most fetal cardiac dimensions, although good correlations were also observed using femoral length and abdominal cross-sectional area. Heart width and heart diameter were used as surrogates of cardiac development, as these measurements showed the best statistical correlation. Quantitative evaluation of fetal cardiac structures can be used to monitor normal and abnormal cardiac development.  相似文献