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Tomato chlorotic dwarf viroid (TCDVd) manually inoculated to transgenic (cv.‘Desiree’) potato plants containing antimicrobial cationic peptides failed to develop symptoms in above ground plant parts, but infected tubers were symptomatic. Plants from the infected tubers (second generation plants) emerged as either severely stunted (bushy stunt isolate, BSI) or tall and symptomless. Molecular characterization of BSI isolates showed TCDVd sequence variants 95 to 98% identical to TCDVd sequences from the database, while a viroid variant identical to TCDVd type isolate (acc # AF162131) was cloned from symptomless plants. The TCDVd BSI variants had novel U165C, GU177-178AA, and UCAC181-184CUUU nucleotide substitutions in the terminal right (TR) domain of the viroid molecule. The cloned viroid cDNAs of the BSI were infectious to experimental (cv. ‘Sheyenne’) tomato plants causing stunted plants with profuse auxiliary shoots. Visual evaluation of the susceptibility of the BSI to 18 potato and 21 tomato cultivars revealed severe symptoms in most cultivars of both species. The progeny variants accumulating in each potato and tomato cultivar exhibited the same novel TR domain in most cultivars, with only a slight variation in a few. The severity of the stunting symptoms induced by TCDVd from BSI isolates in both potato and tomato cultivars has not been noted previously with other TCDVd isolates and, as such, it is proposed that this new isolate be recognized as a distinct genotype. Emergence of this type of sequence variant in commercial fields or commercial tomato greenhouses could potentially cause relevant losses in both crops.  相似文献   
33.
Zinc (Zn) fertilization is important for Zn crop biofortification as well as increasing yields, thus proper Zn recommendations for soil application is needed for Zn deficient soils. The effectiveness of Zn applications was evaluated in different combinations of rates (2.5, 5.0, 7.5, and 10.0?kg?ha?1 per year) and frequencies (initial, alternate, and every year) in rice (Oriza sativa L.) – wheat (Triticum aestivum L.) cropping system in a Zn-deficient upland calcareous soil in the fourth year. Zn applications to rice at 7.5 and 10?kg?ha?1 of alternate year and 5.0 to 10?kg?ha?1 of every year had the highest rice equivalent yield as compared to no-Zn treatment. Hence, Zn application to rice at 7.5?kg?ha?1 at alternate years is the lowest rate at which highest rice equivalent yield of rice-wheat cropping system can be obtained.  相似文献   
34.
The viability of matured oocytes stored in vitro were assessed using carp ovarian fluid (OF) and artificial carp ovarian fluid (ACOF) under different temperature regimes (4, 24, 26, 28 and 30°C) for different storage durations (0, 60, 120, 150 and 180 min). Significantly higher fertilization (74%) was achieved when the oocytes were stored using ACOF and 65% in OF after 180 min at 28°C. Similarly the hatching rates of larvae were significantly higher in the ACOF and OF, that is, 64% and 47%, respectively, after 180 min of storage. The oocytes kept in the storage containers with ACOF having 65% moisture level showed a significantly higher fertilization rate than the 59% moisture level. This study demonstrated that unfertilized matured oocytes (eggs) of rohu can be stored in vitro for 180 min without compromising the viability (fertilization and hatching) to a great extent in OF and ACOF.  相似文献   
35.
The digestible energy (DE) content and the apparent digestibility coefficients (ADCs) of nutrients in common feed ingredients available in Atlantic Canada for haddock, Melanogrammus aeglefinus, feed formulations were determined. Juvenile haddock (mean weight, 93.9±2.1 g) were held in tanks equipped with fecal collection columns and fed practical fish meal‐based diets for 5 weeks. The experimental diets consisted of a reference diet and six test diets, each containing 30% test ingredient, with all diets being supplemented with chromic oxide (Cr2O3, 5 g kg?1) as the inert digestion indicator. Three marine fish by‐products, herring meal (HM), shrimp meal (SM) and crab meal (CRM) and three plant protein supplements, dehulled soybean meal (SBM), canola meal (CAM) and corn gluten meal (CGM) were the test ingredients. The DE content of HM, SBM, CGM, CRM, CAM and SM were 18.3, 18.0, 17.8, 12.4, 10.9 and 8.8 MJ kg?1 respectively. Protein ADCs were 95.9%, 92.2%, 92.3%, 82.0%, 83.0% and 73.5% respectively. Organic matter ADCs were 95.9%, 89.0%, 72.6%, 68.9%, 58.9% and 54.9% respectively. Lipid ADCs were 97.9%, 83.0%, 57.4%, 62.0%, 87.2% and 55.8% respectively. Based upon its high crude protein content and nutrient ADC and DE content, properly processed dehulled SBM was found to be a good plant protein supplement to partially replace HM in haddock feeds.  相似文献   
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Orange rust of sugarcane caused by Puccinia kuehnii was first reported in Florida in 2007. Since then, several sugarcane cultivars that were resistant during the initial epidemics became susceptible within a few years. These shifts in resistance were attributed to the evolution of the pathogen and appearance of new races. To study the variation in virulence of P. kuehnii, healthy leaf pieces of sugarcane cultivars susceptible to orange rust were brush inoculated with isolates of P. kuehnii collected from susceptible cultivars in the field. After inoculation, leaf pieces were placed in an incubator and disease severity based on the number of rust uredinia was determined 2 weeks postinoculation. Isolates of P. kuehnii collected from sugarcane cultivar CP 89-2143, which only showed severe symptoms of orange rust starting in 2011–2012, produced 300%–500% more uredinia on CP 89-2143 than the isolates collected from cultivar CL 85-1040 that has been susceptible since 2007. Sugarcane cultivar CL 85-1040 exhibited high and equivalent numbers of uredinia regardless of the inoculated isolate of the pathogen. These data support the occurrence of pathogenic specialization within P. kuehnii and the existence of at least two races of this pathogen in Florida. Analysis of amplified fragment-length polymorphism among isolates of P. kuehnii from cultivars CP 89-2143 and CL 85-1040 differing in resistance to orange rust revealed genetic variation among rust uredinia. However, this variation was not associated with a specific sugarcane cultivar, suggesting that pathogenic variation was not linked to major, but rather to small genetic changes within the genome of P. kuehnii.  相似文献   
38.
Selection for genetically superior Murrah buffaloes under Network Project on Buffalo Improvement, India, is presently based on milk yield, and it was observed that even in the absence of any direct selection pressure applied on fertility, there has been a downward trend in fertility associated with the selection for milk yield. The aim of the study was to develop selection indices which include fertility besides milk yield in Murrah buffaloes. Data pertaining to 1,224 lactation records spread over a period of 19 years were recorded and analyzed in the study. The negative association of pregnancy rate (fertility) with a 305-day milk yield (?0.08?±?0.04) and wet average (?0.12?±?0.02) indicated the importance of incorporating fertility trait in the construction of selection index. Four types of selection indices were constructed and evaluated. Two indices were developed using expected producing ability 305-days milk yield (EPAMY) with 6.5 and 4 % fat in milk along with expected fertilizing ability (EFA). The other two indices developed consist of expected producing ability wet average (EPA WA) and EFA. The index involving (EPA WA and EFA) was found to be a more effective selection criterion in our herd, as the accuracy of index was more (0.61), in comparison to the index involving EPA MY and EFA. The robustness of selection index was assessed by increasing the relative economic values of included traits by 25 and 50 %, and accuracy of the index remains almost stable without much change. The developed selection strategy involving EPA WA and EFA should be considered for the genetic evaluation of Murrah buffaloes, as it has a potential for maximizing the lifetime reproduction and production performances of the breed.  相似文献   
39.
The effects of oxidized dietary lipid and the role of vitamin E on lipid profile, retained tocopherol levels, and lipid oxidation of juvenile Atlantic cod (Gadus morhua) were evaluated following a 9-week feeding trial. Four isonitrogenous experimental diets containing fresh or oxidized (peroxide value of 94 mequiv/kg) fish oil with or without added vitamin E (alpha-tocopherol or mixed tocopherols) were fed to juvenile cod in duplicate tanks. There was no significant (P > 0.05) influence on major lipid classes of cod liver and muscle by diet with the exception of sterols. Sterols content was increased in liver but decreased in muscle by oxidized dietary oil in the absence of vitamin E. Dietary vitamin E supplementation decreased the sterols level in cod liver but with no significant (P > 0.05) effect on their level in the muscle. Fatty acid composition varied between lipid fractions in muscle tissue and was affected by the diet. Oxidized oil significantly (P < 0.05) decreased the deposition of alpha-tocopherol in liver but not in muscle. gamma- and delta-Tocopherols from dietary tocopherol mixtures were retained at very low levels in liver, but higher retention was observed in muscle tissue. The oxidative state of both liver and muscle, as measured by the 2-thiobarbituric acid reactive substances (TBARS) and headspace propanal, negatively correlated with tissue vitamin E levels. It is suggested that oxidized oil affected juvenile Atlantic cod by causing vitamin E deficiency in certain tissues and that these effects could be alleviated by supplementation of a sufficient amount of dietary vitamin E. The results also indicate that mixed tocopherols were good antioxidants for Atlantic cod, although less effective than alpha-tocopherol alone in many tissues with the exception of muscle, where gamma- and delta-tocopherols were deposited at relatively high levels.  相似文献   
40.
Summary Seed protein profiles of 19 accessions representing seven sections of the genus Arachis were studied using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The general profile showed appreciable homology between these taxa, supporting their classification based on morphology and cross-compatibility relationships. The accessions of section Arachis expressed a high variation confirming inferences from earlier studies. Variation between accessions of a species is limited. Accessions of the section Ambinervosae and Caulorhizae formed one cluster and accessions of sect. Erectoides and Procumbensae formed another. Whereas the representative accessions of sect. Triseminalae and Extranervosae formed two independent clusters. Using the percentage of dissimilarity in electrophoretic bands as a statistical genetic distance between accessions, sect. Arachis (containing the cultivated groundnut, A. hypogaea) is phylogenetically closest to sect. Erectoides followed by Procumbensae, Ambinervosae, Caulorhizae, Triseminalae and Extranervosae, respectively.Submitted as Journal Article No. 1485 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Patancheru, A.P. 502 324, India.  相似文献   
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