Identification of leaf rust resistance genes in common wheat varieties from China and foreign countries

Wheat leaf rust, triggered by Puccinia triticina Eriks(Pt), is among the most important diseases of wheat worldwide. Deploying resistant varieties against leaf rust is the most effective, environmentally-friendly and economic way to control the disease. In the present study, 66 wheat varieties form China and foreign countries were tested with 17 Pt races for gene postulation during the seedling stage in the greenhouse. All the varieties were also planted to identify slow rusting responses to leaf rust at the adult plant stage in Baoding and Zhoukou field trials during the 2016/2017 to 2017/2018 cropping seasons. Moreover, 12 closely linked molecular markers to known leaf rust resistance(Lr) genes were used for assessing all the varieties. The results of both gene postulation and molecular marker identification showed that a total of eight Lr genes, Lr1, Lr10, Lr17, Lr20, Lr26, Lr34, Lr37 and Lr46, either singly or in combination were detected in 32 varieties. Known Lr genes were not identified in the remaining 34 varieties. Seventeen varieties were found to have slow rusting resistance. The resistance sources identified in this study can be used as resources for resistance against leaf rust in wheat breeding programs in China and the respective foreign countries.     

Breed and trait preferences of Sheko cattle keepers in southwestern Ethiopia

Like their smallholder subsistence counterparts in developing countries, breed and trait preferences of Sheko cattle keepers have broad perspectives. Our study has documented breed and trait preferences of Sheko cattle keepers in southwestern Ethiopia—the natural breeding tract of Sheko cattle. Our results showed that due to their multifunctionality, cattle are the most preferred livestock species. Overall, farmers showed slightly more preference to local Zebus over Sheko breed. This is due to voracious feeding behavior of Sheko cattle, which make them less preferable in the face of worsening feed shortage, and due to aggressive temperament of Sheko cattle. This is despite Sheko's outperforming potential over local Zebus in their milk production, draft power, and hardiness. At trait level, overall milk production was consistently reported as the most preferred trait followed by fertility and traction. This trait preference rank has matched with the reported frequency count ranks for Sheko cattle use. However, breed preference rank has not matched with reported trait preference ranks because Sheko excels local Zebus in all the three most preferred traits, but it was ranked second. Therefore, to minimize these conflicting interests, breed management plans for Sheko cattle should target on strategies that help to solve feed shortage problem and to improve feeding practices, and on selection of less aggressive Sheko cattle. Therefore, these strategies should be considered in line with Sheko cattle conservation and genetic improvement programs.     

Genecological zones and selection criteria for natural forest populations for conservation: the case of Boswellia papyrifera in Ethiopia

Rapid changes in land-use in the Combretum–Terminalia woodlands of northwestern Ethiopia are mainly due to the increases in commercial farming and immigration.We used integrated ecological and social data collection techniques,including subdivision of the vegetation zone,vegetation survey,focus group discussions and key informant interviews,to identify genecological zones and set criteria for selection of viable populations of Boswellia papyrifera(Del.)Hochst in Ethiopia for conservation.Interviews of senior experts were supported with a rating method and involved 43 respondents and focused on identifying and weighting criteria and indicators of selection in a participatory way to prioritize populations for conservation.Using mean annual rainfall data,we reclassified the Combretum–Terminalia woodland vegetation region into three moisture zones(wet,moist and dry),and designated them as genecological zones for B.papyrifera conservation.A total of 35 woody species were identified at Lemlem Terara site in Metema district,and the Shannon diversity index and evenness were 2.01 and of 0.62,respectively.There were 405 adult trees,and 10 saplings and3314 seedlings per ha.The trees were medium-sized with overall mean diameter at breast height(dbh) of 16.9(±9.5)cm.Seedling recruitment was poor due to grazing,crop production and fire incidences.Through a multi-criteria decision analysis,five criteria and 20 quantitative indicators were identified and weighted to prioritize populations for conservation.These criteria in their descending order of importance are(1) forest ecosystem health and vitality,(2)forest cover and population structure of B.papyrifera,(3)productive function of the forest,(4) biological diversity in the forest,and(5) socioeconomic benefits of the forest to communities.Multivariate tests in the general linear model revealed significant differences among researchers and nonresearchers in rating the criteria and indicators,but not among foresters and nonforesters.Hence,participatory multi-criteria decision analysis should involve people from various institutions to rectify decisions on conservation of the species.Careful evaluation of the investment policy environment and engaging those government bodies that are responsible to allocate the dry forests for commercial farming is recommended before the proposed criteria are applied to select populations for conservation,thus ensuring subsequent use of the outcomes of such exercises and better reconciling conservation and agricultural production increment goals.     

Effects of drip irrigation levels and planting methods on yield and yield components of green pepper (Capsicum annuum, L.) in Bako, Ethiopia

A field experiment was conducted to investigate the effects of different levels of drip irrigation and planting methods on yield and yield components (number of fruits per plant, number of primary and secondary branches per plant, and plant height) of green pepper (Capsicum annuum, L.) in Bako, Ethiopia. Three irrigation levels (50, 75 and 100% of ET_c) and two planting methods (normal and paired-row planting) were applied. The experiment was laid out in a split plot design, with irrigation levels as main plots and planting methods as sub-plots, in three replications. It was found that the effects of both treatments on yield, number of fruits per plant and plant height of green pepper were highly significant (p < 0.01) whereas the number of primary and secondary branches per plant was affected significantly (p < 0.05). The maximum and minimum values of the yield and yield components were recorded from treatment plots I₁₀₀P (full irrigation level with paired-row planting method) and I₅₀P (50% of ET_c irrigation level with paired-row planting method), respectively, with the exception of plant height. However, the average plant height (cm) recorded from the I₁₀₀N treatment plot was not significantly different from the I₁₀₀P treatment plot. Moreover, it was found that the effect of treatment interactions on both yield and yield components of green pepper was found to be highly significant (p < 0.01). A 50% reduction in irrigation level caused a reduction in yield of about 48.3 and 74.4% under the normal and paired-row planting methods, respectively, whereas, a 25% reduction in irrigation level caused a reduction in yield of about 22.8 and 47.7% under the same planting methods. Under both deficit irrigation levels (I₅₀ and I₇₅), the normal planting method gave higher total yield and yield components of green pepper than the paired-row planting method. Yield response factor (k_y) values of 0.96 and 1.57 were determined for the normal and paired-row planting methods, respectively, suggesting utmost precautions when using the paired-row planting in areas with limited water supply. The results revealed that full irrigation water supply under paired-row planting method (I₁₀₀P) could be used for the production of green pepper in an area with no water shortage. Moreover, it was found that the average yields recorded from the I₇₅ under the paired-row planting method is fairly greater than the national average.     

Impact of four fiber-rich supplements on nutrient digestibility,colostrum production,and farrowing performance in sows

This study aimed to investigate the impact of dietary fiber (DF) sources on sow and litter performance, and apparent total tract digestibility (ATTD) of gross energy (GE) and nutrients. A total of 48 sows were stratified for body weight at mating and randomly assigned to one of four DF sources (mixed fiber [MF], palm kernel expellers [PKE], sugar beet pulp [SBP], or soy hulls [SH]) and fed the diet from mating until farrowing. Within DF treatments, sows were supplemented with one of two extra energy sources (glycerol or sugar dissolved in water), whereas a third group (control) received water from day 108 of gestation until farrowing. The number of total born, live-born, and stillborn pigs; birth time and birth weight of the pigs; farrowing duration; and farrowing assistance (FA) were recorded. Live-born pigs were weighed again at 12 and 24 h after birth to record weight gain, which was used to estimate intake and yield of colostrum. Blood samples were collected once daily from day −3 relative to farrowing until day 1 after farrowing in sows and once from selected pigs right after birth. Fecal samples were collected on day 114 of gestation and colostrum at 0, 12, 24, and 36 h after onset of farrowing. Intake of soluble and insoluble nonstarch polysaccharides (NSP) was greater for SBP (P < 0.001) and PKE (P < 0.001) supplemented sows, respectively, when compared with other groups. Farrowing duration and stillbirth rate were not affected by DF sources, but PKE and SH supplemented sows had greater FA than SBP and MF supplemented sows (P < 0.001). Extra energy supplement did not improve the farrowing performance. Concentration (P = 0.02) and output (P = 0.04) of dry matter in colostrum, and ATTD of GE (P < 0.001) and crude protein (CP; P < 0.001) were lower for PKE supplemented sows than in sows from the remaining groups. Intake of insoluble NSP correlated negatively with ATTD of GE (P < 0.001) and CP (P < 0.001). Concentrations of glucose (P < 0.001), lactate (P < 0.001), CO₂ (P < 0.001), and HCO₃ (P < 0.001) in sows blood were increased with time progress relative to farrowing. Newborn pigs from PKE supplemented sows had greater concentration of lactate (P = 0.02) and lower blood pH (P = 0.02) than the remaining treatments. In conclusion, PKE supplement reduced ATTD of GE and CP, and concentration and output of dry matter in colostrum but increased FA. Results of this experiment indicated that the use of PKE as a fiber source for late gestating sows should be avoided.     

Multi-locus Sequence Analysis (MLSA) of Edwardsiella tarda isolates from fish

Edwardsiella tarda is an enteric fish pathogen that has caused significant economic losses in a range of fish species residing in diverse ecological conditions. Several molecular methods relying on DNA fingerprinting (RAPD, RFLP and ERIC-PCR) and the gyrB gene marker have been used to characterize E. tarda isolates. However, all had drawbacks in resolving power and reproducibility. The present study was aimed at developing a novel Multi-locus Sequence Analysis (MLSA) scheme for genetic characterization of E. tarda isolates originating from multiple sources. MLSA has been described as an effective molecular tool with superior discriminatory power and reproducibility for exploring intra-species genetic diversity of several bacterial species. Nucleotide sequence fragments of eight protein coding housekeeping genes (gyrB, mdh, adk, dnaK, phoR, metG, pyrG and aroE2) were obtained from 23 fish pathogenic E. tarda isolates of different geographical origins, one human isolate and 3 reference strains. The phylogenetic relationships between isolates in individual gene analyses were not consistent, although some common patterns were apparent. Phylogenetic analysis based on concatenated sequences of seven gene loci, however, buffered the conflicting phylogenetic signals and resolved isolates according to their geographical origin and/or fish host. The MLSA revealed two major genetically diverging clusters in E. tarda isolates examined, one cluster representing isolates from fish and the other representing (in the main) human isolates, with E. ictaluri cluster situated in between. The results suggest, therefore, that the fish pathogenic E. tarda isolates may have been previously misclassified and probably represent one or more as yet unrecognized taxa within the genus Edwardsiella. The MLSA described here was robust enough in discriminating E. tarda isolates not only with respect to their geographical origins but also within different hosts from the same geographical location, high-lighting its potential application in tracing the source of infection and understand the epidemiological relationships among isolates of environmental, fish, other domestic animals or human origins.     

30个重要小麦生产品种抗叶锈性基因分析

【目的】小麦叶锈病是影响中国小麦产量的重要病害之一,培育持久抗病品种可以经济、有效地控制该病害。论文通过基因推导结合系谱分析、分子标记及成株抗病鉴定对小麦生产品种中抗病基因进行鉴定,从而确定小麦品种中所携带的抗病基因。【方法】选用18个小麦叶锈菌菌系(PHGQ、THJT、PHJT、KHJS、PHJS、THTT?、KHHT、FHRT、FHJQ、PHTT、THTT?、PHTT、FHTR、FHHT?、FHHT?、TGGT、FHTT、FGMT)接种36个已知抗叶锈病基因载体品种和中国的30个小麦生产品种进行苗期抗叶锈病基因推导,进一步利用9个与已知抗病基因紧密连锁的特异性标记进行标记检测,同时系谱分析法确定供试小麦品种中所携带的已知抗叶锈病基因。为了鉴定小麦品种的成株抗性基因,在2014—2015和2015—2016年度将30个小麦品种、慢锈对照品种SAAR和感病对照品种郑州5389种植于河北农业大学小麦试验田和河南周口黄泛区农场试验田,田间用混合生理小种(FHRT、THTT、THJT)接种进行成株抗叶锈性鉴定,进一步运用软件IBM SPSS Statistics 19.0进行方差分析(ANOVA),根据苗期与成株期的侵染型排除具有主效抗性基因的品种,将田间最终严重度(当达到发病高峰时调查的严重度为最终严重度,final disease severity,FDS)明显小于或与慢锈对照SAAR无显著差异的作为慢锈品种,从而筛选出表现慢锈的小麦品种。【结果】基因推导、系谱分析结合标记检测结果表明,30个小麦生产品种中有4个品种(鄂恩5号、鄂麦14、陕229和西农979)含有抗病基因Lr1,10个品种(鄂恩1号、鄂恩5号、鄂恩6号、贵农16、陕225、陕354、陕715、陕合6号、陕麦509和陕农7859)携带有抗病基因Lr26,2个品种(陕225和小偃81)经分子标记检测含有慢锈抗病基因Lr46,另外还有3个品种(西农979、陕229和贵农16)可能含有基因Lr13,所有供试品种均不含Lr9、Lr10、Lr19、Lr20、Lr24和Lr34抗病基因。根据2年2点的田间抗叶锈病鉴定筛选出18个表现慢锈的品种,且方差分析结果表明各品种间和地点间差异均极显著,年份间差异显著,品种与地点间、品种与年份间差异均极显著,而品种与重复间和重复间均不显著,这表明小麦叶锈病抗性的表达受基因型和环境互作共同影响。【结论】30个小麦品种中共检测到Lr1、Lr26、Lr13和Lr46等4个抗叶锈病基因,其中Lr46为成株抗病基因,通过田间抗性鉴定共检测出18个品种可能携带成株慢锈基因,所有慢锈材料中可能含有未知成株抗叶锈病基因,需要进一步进行遗传鉴定。     

Multilocus sequence analysis revealed a high genotypic diversity of Aeromonas hydrophila infecting fish in Uganda

A multilocus sequence analysis (MLSA) was carried out to delineate Aeromonas hydrophila from fish in Uganda. Five housekeeping genes including recA, gyrB, metG, gltA and pps; and the 16S rRNA gene were amplified and sequenced from a total of nine A. hydrophila isolates. The obtained sequences were edited, and consensus sequences generated for each gene locus. The housekeeping gene sequences were concatenated and phylogenetic analysis performed in MEGA version 7.0.2. Pairwise distances ranged from 0.000 to 0.118, highest within the gltA gene locus and lowest within the 16S rRNA gene. The average evolutionary diversity within isolates from the same source ranged between 0.002 and 0.037, and it was 0.033 between the different sources. Similar tree topologies were obtained from the different gene loci with recA, metG and gyrB being more consistent in discriminating isolates according to sources while the 16S rRNA gene had the lowest resolution. The concatenated tree had the highest discriminatory power. This study revealed that A. hydrophila strains infecting fish in Uganda are of diverse genotypes suggesting different sources of infection in a given outbreak. Efforts to minimize spread of the bacteria across sources should be emphasized to control infections of mixed genotypes.     

Antibody seroprevalences against peste des petits ruminants (PPR) virus in camels, cattle, goats and sheep in Ethiopia

A questionnaire-survey data indicated that 26% of 276 farmers reported the presence of respiratory disease in their herds in 2001. The incidence was perceived as "high" in small ruminants and camels, but as "low" in cattle. Simultaneously, 2815 serum samples from camels (n=628), cattle (n=910), goats (n=442) and sheep (n=835) were tested. The peste des petits ruminants (PPR) antibody seroprevalence was 3% in camels, 9% in cattle, 9% in goats and 13% in sheep. The highest locality-specific seroprevalences were: camels 10%, cattle 16%, goats 22% and sheep 23%. The animals had not been vaccinated against rinderpest or PPR. Antibody seroprevalences detected in camels, cattle, goats and sheep confirmed natural transmission of PPR virus under field conditions.     

Uses and flock management practices of scavenging chickens in Wolaita Zone of southern Ethiopia

Rearing of scavenging chickens is among the most commonly practiced farm activities in Ethiopia. This system is dominated by indigenous chickens. Output from indigenous chickens is low due to poor management and absence of intense selection that is intended to improve economically important traits. This showed that village chickens are rather evolved for adaptation traits. However, the level of risk is low, and this has made rearing of scavenging chickens a choice of farm activity for smallholder farmers. The objective of this study was to characterize the scavenging chickens’ production system in Wolaita Zone. Single-visit survey involving individual interview of 119 farmers and 6 focus group discussions was used to collect the data. Our results showed that rearing of scavenging chickens was constrained especially by disease and predation problems. However, farmers proposed a set of solutions to minimize the effect of these problems. Rearing of scavenging chickens fulfils the multi-functional need of the society. This system has special features because it can sustain in its own without the need for modern commercial chicken farming facilities. However, farmers also reported the drawbacks of rearing of scavenging chickens and these mainly include uproot of garden crops and tiresomeness of the night watching. Selection of chickens was mainly depending on physically observed traits like body size and plumage colour. The initial foundation flock was mainly obtained from the local market. The ideal place for scavenging chickens production is the one that has intermediate weather condition and has some trees that can be used as shade; however, it was substantiated that it has to be free from bush and shrubs, weeds and wet lands. Therefore, these pieces of knowledge embedded among smallholder farmers need to be well documented and synthesized to design an appropriate type of technology packages that can be communicated back to farmers to improve productivity of the scavenging chickens.