Genetics of grain yield and other agronomic characters in t'ef (Eragrostis tef Zucc Trotter). II. The triple test cross     

Hailu Tefera  W.E. Peat 《Euphytica》1997,96(2):193-202

The normal and selfed families of the triple test cross were employed to detect gene action in t'ef for grain yield and other useful agronomic characters in the breeding programme. Cultivars Kay Murri and Fesho were used as L₁ and L₂ testers, respectively. Eight randomly selected cultivars and two released varieties (DZ-01-354 and DZ-01-196) were crossed with the testers L₁, L₂ and L₃ (the F₁ of L₁ × L₂). In the case of the selfed families, 14 cultivars and two released varieties were used for crossing with the testers. The normal families were grown on an Inceptisol developed from volcanic ash whilst the selfed families were grown on a pellic Vertisol at the Debre Zeit Agricultural Research Centre, Ethiopia. The rainfall during the experimental season was 463 mm. Epistasis was detected for grain yield, yield per panicle, panicle weight, plant weight, harvest index, tiller number, panicle length, culm diameter, days to heading and days to maturity in the normal families of the triple test cross (TTC) of t'ef. Similarly the characters grain yield, yield per panicle, panicle weight, plant height, panicle length, days to heading and days to maturity showed epistasis in the selfed families of the TTC. Epistatic interaction was not important for shoot biomass and for harvest index (for the transformed data) in this family. Therefore, both the normal and selfed families of the TTC were in agreement with regard to detecting epistasis for grain yield, yield per panicle, panicle weight, panicle length, days to heading and days to maturity. Significant additive (D) and dominance (H) components were estimated for the characters in both families, although the magnitudes might have been inflated due to epistasis. The dominance component for panicle length was unimportant in both families of the TTC and as a result the additive components were not biased. In general, the additive, dominance and epistatic components were important in t'ef. Since the crop is self-fertilized only the additive and additive × additive terms are important to develop pure breeding varieties. Therefore, selection for superior segregants should start in advanced generations as homozygosity increases. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

酶制剂对獭兔生产性能影响的研究     

蔡海路  苏加义 《安徽农学通报》2007,13(12):152-153

选择30日龄和90日龄的断奶獭兔各30只,每个日龄段的獭兔分为两组,每组15只;采用日粮配方相同,对照组不加酶制剂,两个试验组各添加酶制剂0.5%.试验结果表明:30 日龄的试验组比对照组日增重提高19.32%,差异显著(P＜0.05),90日龄组添加酶制剂的效果不明显(P＞0.05);30日龄对照组平均日增重为18.01 g,90 日龄组则为14.81 g;试验的30日龄组日增重为22.23 g,90日龄为15.58 g,两组差异极显著(P＜0.01).同一日粮添加相同剂量的酶制剂,30日龄的料/重比90日龄低11.48个百分点.  相似文献   

Assessment on major factors that cause skin rejection at Modjo export tannery,Ethiopia     

Berhanu W  Negussie H  Alemu S  Mazengia H 《Tropical animal health and production》2011,43(5):989-993

A study was conducted from November 2009 to March 2010 with the objective of identifying the major causes of skin rejection on fresh, pickled, and wet blue skins at Modjo Mesaco Global tannery. A total of 401 fresh and 1,873 pickled and wet blue skins from the routine production system of the tannery were used. Overall, high prevalence of sheep ked (100%) followed by biting louse (64.4%), tick (50%), and sucking louse (45.8%) were observed on fresh sheep pelts, while, on fresh goat pelts, a high prevalence of sucking louse (54.5%), followed by tick (50%), and biting louse (35.5%) were observed. From the total of 90 rejected pickled and wet blue skins of sheep and goats, 98.8% were “ekek” and scratch, 85.6% sheep and goat pox, 74% poor substance, 73.3% heat, 72.2% scar, and 52.2% knife cut-in skins. Large number of skins rejections was recorded in large-sized skins (29.8%), and the lowest observed was in medium-sized skins (11.1%). There were highly statistically significant association (p < 0.05) between size and grades of shoat skins. Ekek and scratches together with sheep and goat pox were the common skin defects that hamper skin quality. However, there was no significant association (p > 0.05) between sheep and goat skins. Ekek and scratch caused high rejection of skin and entailed serious economic loss in terms of foreign exchange earning to Ethiopia. Therefore, the main causes of skin rejection and factors that cause downgrading of skin should be controlled.  相似文献   

The effect of long-term Maresha ploughing on soil physical properties in the Central Rift Valley of Ethiopia     

Birhanu Biazin  Leo Stroosnijder  Melesse Temesgen  Abdu AbdulKedir  Geert Sterk 《Soil & Tillage Research》2011,111(2):115-122

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The rice genome and the minor grains     

Goodman RM  Naylor R  Tefera H  Nelson R  Falcon W 《Science (New York, N.Y.)》2002,296(5574):1801

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介孔氧化硅SBA-15对铯的吸附性能研究   总被引：1，自引：0，他引：1  

江玲  龚霞  刘淑娟  马建国  罗明标  林海禄  丁志昆 《江西农业大学学报》2015,(2):363-368

SBA-15是具有较大孔径和良好的热稳定性的多孔硅基分子筛,在吸附分离领域有着广阔的应用前景。合成了介孔硅基材料SBA-15,对其进行了TEM和FTIR表征,并进行了SBA-15对铯的吸附性能研究,探讨了不同的p H值,铀初始浓度,吸附材料用量,反应时间以及离子强度等条件对吸附性能的影响。结果表明,在p H=6,吸附时间120 min,铯初始浓度为40 mg/L时,SBA-15对铯的吸附容量达到26.31 mg/g。较高的p H值有利于铯的吸附,而离子强度对吸附明显有抑制作用。吸附等温线拟合结果符合Langmuir等温模型,拟一级动力学模型能较好地描述反应动力学。  相似文献   

Sero-prevalence and risk factors study of brucellosis in small ruminants in Southern Zone of Tigray Region, Northern Ethiopia   总被引：2，自引：2，他引：0  

Teshale Teklue  Tadele Tolosa  Getachew Tuli  Belay Beyene  Birhanu Hailu 《Tropical animal health and production》2013,45(8):1809-1815

This study reports a prevalence and risk factor survey of brucellosis in small ruminants in Southern Zone of Tigray Region, Northern Ethiopia between October 2011 and April 2012 to determine the sero-prevalence of small-ruminant brucellosis and to identify associated risk factors for the occurrence of disease in small ruminants under extensive production system. Multistage random sampling was followed to select locations, flocks, and individual animals. Laboratory analysis of serum samples provided sero-prevalence estimates for flocks and geographic location. Information on risk factors at the individual and flock level was obtained by examination of individual animal and a questionnaire interview to flock owners. The overall individual animal-level sero-prevalence of brucellosis in small ruminants was 3.5 % and flock level sero-prevalence was 28.3 %, and the within-flock sero-prevalence was ranged from 0 % to 22.2 % based on the Complement Fixation Test. Multivariable logistic regression showed that the major risk factors for flock level sero-positivity were flock size and abortion history. This study showed that small-ruminant brucellosis is prevalent in the study area. Larger flock size and history of previous abortion in the flock were major risk factors identified for sero-positivity of small-ruminant brucellosis.  相似文献   

Report on the 42nd joint meeting of the DPG-working group Nematology and the working group “free living nematodes”     

Daub  Matthias  Hakl  Ulrike  Maressa  Beira Hailu  Dehne  Heinz-Wilhelm  Hallmann  Johannes  Kiewnick  Sebastian  Eberlein  Caroline  Heuer  Holger  Moos  Jan H  Paulsen  Hans M  Westphal  Andreas  Sturhan  Dieter  Kiewnick  Sebastian  Wolf  Stefanie  Bühlmann  Andy  Frey  Jürg  Nuaima  Rasha  Heuer  Holger  Westphal  Andreas 《植物病害和植物保护杂志》2014,121(4):187-189

Journal of Plant Diseases and Protection -  相似文献   

Genetic and phenotypic parameter estimates for reproduction traits in indigenous Arsi-Bale goats     

Kebede T  Haile A  Dadi H  Alemu T 《Tropical animal health and production》2012,44(5):1007-1015

The study was conducted to evaluate reproductive performances and estimate genetic parameters for reproduction traits in Arsi-Bale goats. A total of 792 kidding records collected from 2001 to 2007 were used. Parity of dam, year, season and type of kidding were investigated as fixed effects by PROC GLM of SAS. Derivative-Free Restricted Maximum Likelihood (DFREML) method was used to estimate genetic parameters by fitting four animal models. Parity of dam and year of kidding influenced (P < 0.05) all the traits. The overall means for age at first kidding (AFK), kidding interval (KI), litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB), litter weight at weaning (LWW), abortion and dystocia were 574.9 ± 8.3 days, 280.0 ± 13.7 days, 1.6 ± 0.03, 1.37 ± 0.03, 3.7 ± 0.08 kg, 9.11 ± 0.38 kg, 3.8% and 0.13%, respectively. The estimates of direct additive heritability for the traits, except for abortion and dystocia, under the best model (direct animal for AFK and repeatability model for other traits) were 0.245 ± 0.19, 0.060 ± 0.08, 0.074 ± 0.05, 0.006 ± 0.05, 0.125 ± 0.05, 0.053 ± 0.07, respectively, while the corresponding permanent environmental effects were 0.00 ± 0.00, 0.07 ± 0.07, 0.08 ± 0.05, 0.172 ± 0.06, 0.03 ± 0.04 and 0.07 ± 0.05, respectively. Repeatability estimates for KI, LSB, LSW, LWB and LWW were 0.13, 0.15, 0.18, 0.16 and 0.12, respectively. Genetic correlations between reproductive traits vary from medium to high. Arsi-Bale goats have good reproductive performance with low incidence of reproductive disorder. Except for AFK, other traits have low estimates of heritabilities with high genetic correlation among the traits. Repeated measures of the traits are needed before deciding to keep or cull the animal.  相似文献   

Smallholder goat breeding and flock management practices in the central rift valley of Ethiopia     

Kebede T  Haile A  Dadi H 《Tropical animal health and production》2012,44(5):999-1006

The study was conducted in the central rift valley of Ethiopia to define Arsi-Bale goat keepers’ breeding objectives and breeding practices and to describe flock management practices and rate of inbreeding in Arsi-Bale goat population. Two-stage sampling techniques were employed to select study sites and 202 respondents. Semistructured questionnaire and group discussion were used to collect the required information. Data were analyzed using statistical package for social science. Rate of inbreeding in the population and indices were also calculated. On average, each respondent holds around 12 goats in which 30.7, 66.6 and 2.7% were males, females and castrates, respectively. The most important purpose of goat production in the study area was for milk utilization. Farmers have multiple breeding objectives and they considered both subjective and objective selection criteria with slightly more emphasis on morphological characteristics for buck selection than replacement doe selection. Only 39.1% (n = 79) of respondents have their own breeding bucks. None of the respondents practiced controlled mating. Average rate of inbreeding in the population was around 0.20. Arsi-Bale goats are found to be adaptive to the prevailing condition. Therefore, any breed improvement strategy to be designed or implemented in the study area and other similar areas should consider important traditional breeding practices.  相似文献