Genetic analysis of tropical maize inbred lines for resistance to maize lethal necrosis disease     

Yoseph Beyene  Manje Gowda  L. M. Suresh  Stephen Mugo  Michael Olsen  Sylvester O. Oikeh  Collins Juma  Amsal Tarekegne  Boddupalli M. Prasanna 《Euphytica》2017,213(9):224

Maize lethal necrosis (MLN) disease is a recent outbreak in eastern Africa and has emerged as a significant threat to maize production in the region. The disease is caused by the co-infection of Maize chlorotic mottle virus and any member of potyviridae family. A total of 28 maize inbred lines with varying levels of tolerance to MLN were crossed in a half-diallel mating design, and the resulting 340 F₁ crosses and four commercial checks were evaluated under MLN artificial inoculation at Naivasha, Kenya in 2015 and 2016 using an alpha lattice design with two replications. The objectives of the study were to (i) investigate the magnitude of general combining ability variance (σ _GCA ² ) and specific combining ability variance (σ _SCA ² ) and their interaction with years; (ii) evaluate the efficiencies of GCA based prediction and hybrid performance by means of a cross-validation procedure; (iii) estimate trait correlations in the hybrids; and (iv) identify the MLN tolerant single cross hybrids to be used as female parents for three-way cross hybrids. Results of the combined analysis of variance revealed that both GCA and SCA effects were significant (P < 0.05) for all traits except for ear rot. For MLN scores at early and late stages, GCA effects were 2.5–3.5 times higher than SCA effects indicating that additive gene action is more important than non-additive gene action. The GCA based prediction efficiency for MLN resistance and grain yield accounted for 67–90% of the variations in the hybrid performance suggesting that GCA-based prediction can be proposed to predict MLN resistance and grain yield prior to field evaluation. Three parents, CKDHL120918, CML550, and CKLTI0227 with significant GCA effects for GY (0.61–1.21; P < 0.05) were the most resistant to MLN. Hybrids “CKLTI0227 × CML550”, “CKDHL120918 × CKLTI0138”, and “CKDHL120918 × CKLTI0136” ranked among the best performing hybrids with grain yield of 6.0–6.6 t/ha compared with mean yield of commercial check hybrids (0.6 t/ha). The MLN tolerant inbred lines and single cross hybrids identified in this study could be used to improve MLN tolerance in both public and private sector maize breeding programs in eastern Africa.  相似文献   

Effects of pimobendan on myocardial perfusion and pulmonary transit time in dogs with myxomatous mitral valve disease: a pilot study          下载免费PDF全文

SM Apple  G Menciotti  L Braz‐Ruivo  S Crosara  J Häggström  M Borgarelli 《Australian veterinary journal》2016,94(9):324-328

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Comparison of worm control strategies in grazing sheep in Denmark.     

ME Boa  SM Thamsborg  AA Kassuku  HO B?gh 《Acta veterinaria Scandinavica》2001,42(1):57-69

Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.  相似文献   

Identification of galegine, an isoprenyl guanidine, as the toxic principle of Schoenus asperocarpus (poison sedge)     

CR HUXTABLE  PR DORLING  SM COLEGATE 《Australian veterinary journal》1993,70(5):169-171

SUMMARY An Isoprenyl guanldine, galegine, was isolated from the Western Australian sedge Schoenus asperocarpus (Cyperaceae). Synthetic galegine was shown to reproduce the clinical and pathological features of poisoning by this plant. Preliminary results suggest that the massive thoracic effusion observed in sedge poisoning is the result of a direct effect on pulmonary vascular permeability.  相似文献   

Residues from long-acting antimicrobial preparations in injection sites in cattle   总被引：2，自引：0，他引：2  

H MAWHINNEY  SM OAKENFULL  TJ NICHOLLS 《Australian veterinary journal》1996,74(2):140-142

Objective To investigate tissue residues of two longacting oxytetracycline (OTC) preparations in cattle.
Design A randomised drug residue trial.  

Animals

Two hundred and forty beef cattle in 24 groups of ten.
Procedure Two blind-coded 200 mg/mL OTC preparations were used in five treatment regimens of various combinations of injection sites (from one to five) and administrations (one or two). Five cattle from each group were slaughtered at 21, 30 and 60 days after injection and the injection site, urine, kidney and diaphragm muscle analysed for residues.
Results The OTC concentration exceeded the maximum residue limit in kidney in animals slaughtered 21 days after treatment, which is the prescribed withholding period. Concentration at the injection site was much greater than the maximum residue limit 30 days post-treatment, but not 45 days post-treatment. The residue was smaller when OTC had been injected in multiple sites. There was no difference between the two OTC preparations.
Conclusion A review of the maximum injection volume, site of injection and the withholding period is needed for long-acting OTC formulations.  相似文献   

Endocrine Disruptors and Other Food-contaminating Environmental Pollutants as Risk Factors in Animal Reproduction     

SM Rhind 《Reproduction in domestic animals》2008,43(S2):15-22

Pollutants of many chemical classes, derived primarily from anthropogenic activities, are ubiquitous in the environment, persistent, biologically available and can exert adverse effects on the reproductive and other, indirectly related, physiological systems. Food is generally considered to be the major route of animal exposure in vertebrate species but the relative contributions of other routes of exposure such as through lungs, gills or skin are not well studied and may be of importance for certain animal groups, depending on their immediate environment. Animals are particularly sensitive to exposure during developmental stages but the pattern of exposure to chemicals is likely to be different to that of adults. Quantification of the risk posed by the ingestion of pollutants in food is complex and depends on many factors including species, diet composition, duration of exposure to the food, efficiency of pollutant absorption, subsequent metabolism, sensitivity of target organs and stage of development. While the effects of high doses of single chemicals are proven, dietary exposure to pollutants generally involves prolonged, low-level exposure to a large number of compounds, each of which has different chemical characteristics, exerts different biological effects and is present at varying concentrations. Thus, while exposure to pollutants through feed is undoubtedly a significant risk factor for many species and may be the most important one for many terrestrial vertebrates, other routes of exposure may be more important in other groups.  相似文献   

Determination of theanine in commercial tea by liquid chromatography with fluorescence and diode array ultraviolet detection   总被引：1，自引：0，他引：1  

Thippeswamy R  Gouda KG  Rao DH  Martin A  Gowda LR 《Journal of agricultural and food chemistry》2006,54(19):7014-7019

Two liquid chromatographic methods that involve precolumn derivatization with o-phthaladehyde (OPA) and phenylisothiocyanate (PITC) with fluorescence and diode array UV detection for the determination of theanine have been developed. The chromatographic separations were achieved by reverse-phase high-performance liquid chromatography using octadecyl columns and gradient elution. The methods were applied to evaluate the theanine content of commercial tea leaves. The coefficient of variation of the peak area repeatability for within day (n = 8) and between day (n = 8 over 10 days) was lower than 3% for both of the methods. The estimated limit of detection (LOD) and limit of quantitation (LOQ) for the OPA method was 0.12 and 0.35 microg theanine, respectively. The PITC method was 500-fold more sensitive with LOD and LOQ values of 0.25 and 0.75 ng, respectively. The theanine content of the commercial tea samples varied from 2-5 mg/g leaf. The overall % recoveries for these methods ranged from 93-99.3. The sensitivity and simplicity of the method render them suitable for use in quality control laboratories.  相似文献   

Rust Resistance and its Stability in Lines of Varying Productivity in Groundnut (Arachis hypogaea L.)     

M. V. C. Gowda    V. Akunachalam  A. Bandyopadhyay 《Plant Breeding》1990,105(3):229-237

Twenty six lines of groundnut (Arachis hypogaea L.) of varying productivity were tested for yield under four treatments involving fungicidal control of rust and leafspots. Disease severity was measured at two stages of growth, namely 70 days (stage 1) and 90 days after sowing (stage 2). Instead of pod yield, a score (based on an Isd test and grouping over pod yield, shelling %, 100-kernel weight and % residual green leaf area at stage 2) was used to define performance status of the lines. A study of various character combinations revealed the importance of % residual green leaf area at both stages 1 and 2 in predicting the relative yield performance of lines. This result was obtained by comparing the % agreement of the status of lines given by a particular character set with performance status and was confirmed by a multiple regression analysis of pod yield on all other traits. Seven lines and three progenitor parents showed stability of performance with respect to rust resistance. They included lines derived from crosses between the national check, ‘Robut 33—1’, as one parent and either a rust resistant genotype, NC Ac 17090 or an early Russian accession of (Spanish type) ‘Chico’, as the other. It was suggested that breeding programmes should take into account performance status based on yield and disease severity instead of pod yield alone.  相似文献   

Identification of diverse germplasm lines for agronomic traits in a chickpea (Cicer arietinum L.) core collection for use in crop improvement     

H.D. Upadhyaya  S.L. Dwivedi  C.L.L. Gowda  S. Singh 《Field Crops Research》2007,100(2-3):320-326

Utilization of exotic and diverse germplasm is needed to enhance the genetic diversity of cultivars. Genetically diverse lines provide ample opportunity to create favorable gene combinations, and the probability of producing a unique genotype increases in proportion to the number of genes by which the parents differ. Representative core collections (10% of the entire collection) have been suggested as a means to identify useful parents for crop improvement programs. The chickpea core collection (1956 accessions) was evaluated for 14 agronomic traits in two seasons to identify diverse agronomically superior chickpea germplasm. Season (year) and genotypic effects were significant for 13 of the 14 traits, while genotype × season effect was significant for 8 traits. The desi, kabuli, and intermediate type chickpeas differed significantly for days to maturity, basal secondary branches, pods per plant, seed yield, and 100-seed weight. In comparison to controls, 12 accessions flowered early, 15 produced greater seed yield, and 29 had greater 100-seed weight. Based on days to 50% flowering, pods per plant, seed yield, and 100-seed weight, 19 desi, 15 kabuli and 5 intermediate type chickpea germplasm lines originating from 10 countries were selected. The selected desi accessions produced 8.5% more seed yield and had 32% larger seeds than the control cultivar Annigeri while the selected kabuli accessions yielded at par with control L 550 but had 84% larger seeds. The 39 selected accessions and two control cultivars (Annigeri and L 550) were grouped by their first five principal components (PCs) into three clusters. Cluster 1 consisted of early maturing large-seeded kabuli types, cluster 2 early and late maturing desi types, and cluster 3 late maturing intermediate and kabuli types. Clusters 2 and 3 accessions had small to medium sized seeds. These accessions can be used in chickpea breeding programs to develop high yielding desi and kabuli cultivars with a broad genetic base.  相似文献   

Relation of the amyloid beta protein precursor to heparan sulfate proteoglycans     

D C Gowda  R K Margolis  B Frangione  J Ghiso  M Larrondo-Lillo  R U Margolis 《Science (New York, N.Y.)》1989,244(4906):826-828

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