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Molecular detection of Cucumber mosaic virus in various chrysanthemum cultivars was attempted by RT-PCR and Southern hybridization tests using CMV specific primers and cloned probes, respectively. A pair of primers was designed from a conserved region of the Cucumber mosaic virus coat protein (CMV-CP) gene, capable of amplifying a product of ~650 bp from various CMV strains. RT-PCR using the total nucleic acid from infected leaf samples and the specific primers resulted in positive amplification of an expected size band of ~650 bp in most of the samples. The identity of the PCR amplicons was checked by Southern hybridization using the a32P-labelled DNA probes prepared from the cloned coat protein gene of a well-identified strain of CMV isolated from Amaranthus. Positive signal of hybridization of PCR products and CMV probes confirmed the identity of fected chrysanthemum samples.

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Two highly resistant genotypes of wheat viz. HD 29 and DWL 5023 and one highly susceptible genotype WL 711 against Karnal bunt (KB) disease were studied for their difference in morphological features, growth para­meters and isozyme patterns. It revealed that both the resistant geno­types were bearing higher number of spikelets with short internodes in the spike as compared to the susceptible genotype. In contrast WL 711 had significantly higher number of stomata in sheaths, flag leaf base, booted glumes and rachis. The hair count was significantly high on the glumes and rachis of HD 29 and DWL 5023 than on WL 711. HD 29 possessed significantly narrow glume opening distance between lemma and palea followed by DWL 5023 and WL 711. Moreover, the period between ear emergence and anthesis was short in HD 29 followed by DWL 5023 and WL 711. Out of the twelve isozyme systems performed using seeds and seedlings of the genotypes, majority of them gave rise to comparatively higher number of bands in HD 29 and DWL 5023 than in WL 711. How­ever, specific band(s) for each genotype were very less. Cluster infor­ma­tion was the same for morphological data and isozymic banding patterns in Unweighted Pair Group Method with Arithmetic Averages (UPGMA) analysis where both the resistant genotypes together formed a cluster leaving susceptible genotype alone in a separate cluster. Comparison between morphological features and isozyme patterns of the wheat genotypes in relation to KB disease is discussed.

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Zinc is essentially required for crop growth and its insufficient supply to the plants may severely limit the yield traits of a crop. A field experiment was performed during rabi season of 2009–10 and 2010–11 to evaluate the performance of different wheat genotypes under different levels of zinc namely 0 kg ZnSO4 ha−1, 20 kg ZnSO4 ha−1 and 20 kg ZnSO4 ha−1 along with foliar spray of 0.5% solution of ZnSO4. Genotypes responded positively in terms of tiller number, grain and biological yield, spikelet length, spikelet number, grain number and thousandgrain weight. The best response was observed with the application of 20 kg ZnSO4 ha−1 along with foliar spray of 0.5% solution of ZnSO4. Zinc application brought about a maximum increase of 58.6% in tiller number, 63.7% in thousand-grain weight, 40.5% in biological yield, 66.1% in grain yield irrespective of genotypes and the year of study. Wheat genotypes exhibited a variation in their performance which has been exploited in this study. Genotypes UP-262, PBW-175, PBW-343 were found to be superior for one or the other yield contributing factors.

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Acta Agronomica Hungarica
Authors:
S. P. Saikia
,
S. P. Saikia
,
V. Jain
,
V. Jain
,
G. C. Srivastava
, and
G. C. Srivastava

Research over the last few years has shown that inoculation with nitrogen-fixing bacteria of the genus Azorhizobium presents an alternative for (or supplement to) chemical fertilization, mainly due to the capability of the bacteria to produce plant growth- promoting hormones. The Azorhizobium caulinodans strain ORS 571 in combination with 2,4-D was able to colonize the root interior of an Indian maize cultivar. After transplanting to pots, it was noticed that nodulated and Azorhizobium -treated plants showed higher chlorophyll content in the leaf and enhanced nitrate reductase activity, leading to higher yield as compared to the control plants (non-nodulated). A plant growth-promoting effect was clearly visible in all inoculated plants examined. nodulated plants treated with Azorhizobium had higher physiological activities as compared to plants treated only with Azorhizobium . Azorhizobium therefore creates potentially better symbiosis in the form of para -nodules and promotes a higher level of nitrogen fixation, leading to better growth and plant development, with reduced requirements for chemical fertilizers.

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A two-year field experiment was conducted to study the effect of three zinc levels 0, 20 kg ZnSO4 ha−1 and 20 kg ZnSO4 ha−1 + foliar spray of 0.5% ZnSO4 solution on plant height, leaf area, shoot biomass, photosynthetic rate and chlorophyll content in different wheat genotypes. Increasing zinc levels was found to be beneficial in improving growth and physiological aspects of genotypes. Soil application + foliar spray proved to be the best application in improving all the parameters. Zinc application brought about a maximum increment limit of 41.8% in plant height, 101.8% in leaf area, 86% in shoot biomass and 51.1% in photosynthetic rate irrespective of stages and year of study. A variation was found to occur among genotypes in showing responses towards zinc application and PBW 550 was found to be more responsive.

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