Comparative studies on some yield contributing traits of wheat sown in binary mixtures

Cultivar mixtures have been suggested as ways to increase crop productivity. This field study was conducted to investigate the competition among five cultivated varieties of wheat (Triticum aestivum L.) for the traits like plant height, flag leaf area, fertile tillers per plant, spike length, spikelets per spike, spike density, grain weight per spike, and seed index in relation to competition with yield per plant. It was observed that cultivar mixtures ought to be more productive than corresponding pure stands. Four binary combinations of Seher2006-Kohistan97, Farid2006-SH2002, SH2002-Shahkar95, and SH2002-Kohistan97 were superior in performance, showing land equivalent ratio (LER) values greater than one for plant height, fertile tillers per plant, spike density, grain weight per spike, and grain yield per plant. It was observed that the performance of binary mixtures was mainly due to the increased average performance in spike density, grain weight per spike, and grain yield per plant. The competitive ability of wheat varieties in mixtures was independent of each other for the respective traits, which lead to cumulative effects for the increased performance within the associates in mixtures.     

Occurrence of Cucumber mosaic virus Subgroup IA in tomato in Pakistan

Journal of Plant Diseases and Protection - Infection of tomato in Faisalabad, Pakistan with subgroup IA strain of Cucumber mosaic virus (CMV) is reported for the first time. The virus was detected...     

An appropriate plot area for analyzing canopy cover and tree species richness in Zagros forests

In order to make the sampling procedure more efficient and more accurate to study the tree species richness and canopy cover, the appropriate plot size was calculated in the this study. The sampling was carried out using 48 four-hectare plots, each with 13 sub-plots of different plot sizes and 7 one-hectare plots, each with 7 sub-plots. The result of this study showed that 300 ARE plot size was determined as the best area for 1-5% density class, 125 ARE plots for 5-10% class, 150 ARE for 10-25% class, 100 ARE for 25-50% class and 75 ARE plot size to sample >50% density class, in 95% confidence level. Consequently, using 100 ARE sampling plots is suggested for all density classes in central Zagros forests.     

Ovipositional preference and life history parameters of Lixus incanescens (Coleoptera: Curculionidae) on selected sugar beet cultivars

Ovipositional preference and life history parameters of Lixus incanescens were studied on six sugar beet cultivars: Ardabili, Aras, Persia, Flores, Laetitia and Rosire. In both no-choice and free-choice tests, females of L. incanescens laid fewer eggs on Persia and Laetitia compared with Ardabili, Aras, Flores and Rosire. In performance experiments, the pre-imaginal stages developed slower and survived lower on Persia and Laetitia than on Ardabili, Aras and Flores. The intrinsic rate of natural increase and the population growth rate were lowest on Persia (r_m = 0.126 day^?1 and λ = 1.134 day^?1) among the tested cultivars. Petiole diameter and length were positively correlated with pre-imaginal survival rate (r² = 0.96 and r² = 0.98, respectively); therefore, thinner and shorter petioles in Persia and Laetitia led to an increased pre-imaginal mortality. These results suggest that Persia and Laetitia express promising traits that can be an integral component of sugar beet breeding for resistance to L. incanescens.     

Intrauterine iodine administration is superior to antibiotics for reconception after late-embryonic losses in dairy cows

This field study was conducted to compare conception and insemination efficiency responses to intrauterine polyvinylpyrrolidone-iodine (PVP-I) and antibiotic (AB) treatments in dairy cows that experienced pregnancy loss. Data were collected from lactation cows with a history of pregnancy loss 27 to 70 days post-insemination (n = 97) during the 1st to 3rd lactation (days in milk = 196 ± 28). Cows were subjected to 1 of 3 treatments: i) 50 mL saline solution intrauterine infusion (S; n = 23); ii) 2% PVP-I (n = 42); or iii) 150 mg of amoxicillin trihydrate and 40 mg/mL gentamicin sulphate (n = 32). All cows followed the progesterone-based fixed-time insemination protocol. Data were analyzed by Chi-square test and 1-way analysis of variance. The PVP-I treatment (n = 25; 59.5%) was as effective as the AB treatment (n = 19; 59.4%), compared to the S treatment (n = 5; 21.7%) to achieve a new conception. The cows in group PVP-I conceived in a shorter time than those in group AB (46.0 ± 8.7 days versus 105.0 ± 10.0 days; P < 0.05) with a more efficient insemination to conception ratio (2.32 ± 0.43 versus 4.10 ± 0.32; P < 0.05). Data suggest that intrauterine PVP-I administration is superior to intrauterine AB administration in rescheduling reproductive protocol upon late embryonic and fetal losses.     

Effects of foliar application of calcium chloride and urea on quantitative and qualitative characteristics of pomegranate fruits

The effects of urea and calcium chloride and their combinations on qualitative and quantitative characteristics of pomegranate fruits were studied over 2 years. Aqueous solutions of urea at 0%, 0.5%, 1% and 2% and calcium chloride at 0%, 2% and 4% were applied on two branches of pomegranate (Punica granatum L. cv Malase-Yazdi) at full bloom (FB) and 1 month after full bloom (1MAFB) stages. Urea at concentrations of 1% and 2% significantly increased aril size, fruit length and diameter. Calcium chloride at concentrations of 2% and 4% significantly increased average fruit weight and ascorbic acid (AA) content. Both urea and calcium chloride increased soluble solid content (SSC) at all of the used concentrations. In the first time of spraying, higher level of treatments reduced titratable acidity (TA), but the second time of spraying did not significantly affect the TA.     

Spatial modeling of soil salinity using multiple linear regression,ordinary kriging and artificial neural network methods

Salinity as an important property of soil plays a major role in reducing the fertility in the world. Accurate information about the spatial change of soil salinity is essential for sustainable soil management and utilization in agriculture lands. For this purpose, 150 soil samples were collected from Dashte-e-Tabriz Iran and tested and soil salinity was estimated by land surface parameters including elevation, aspect, length of slope, wetness index, slope and normalized difference vegetation index as basic parameters. In order to model and predict the salinity, ordinary kriging (OK), artificial neural networks (ANN) and multiple linear regressions (MLR) were used. Accuracy of models was evaluated by the coefficient of determination (R²), root mean square error (RMSE) and mean absolute error (MAE). Based on Pearson correlation, elevation, normalized difference vegetation and wetness indices were selected for soil salinity spatial modeling from six land surface parameters. The results showed that the ANN had the lowest RMSE and highest R2. The values of R2, RMSE and MAE were 0.36, 25.89 and 17.06 for regression and 0.56, 17.70 and 13.05 for OK and 0.69, 16.06 and 11.60 for ANN, respectively, which indicated more accuracy of ANN in comparison with MLR and OK.     

Fabrication of hollow nanofibrous structures using a triple layering method for vascular scaffold applications

This study aims to develop a new approach for fabricating hollow nanofibrous yarns by engineering a triple-layer structure (polyvinyl alcohol (PVA) multifilament core surrounded by a layer of PVA nanofibers and a polylactic acid (PLA) nanofiber outer layer). After fabrication of this 3-layer structure, the core portion was extracted, leaving the outer layer intact after dissolving the PVA nanofibers in water. To determine the optimum thickness of the outer layer, hollow nanofiber yarns with five different thicknesses were produced. A hollow nanofiber yarn was also produced using a common method to enable comparison of the methods. In the common method, a core sheath yarn consisting of a PVA multifilament core and a PLA nanofiber outer layer was fabricated, and a hollow yarn was produced by placing the core yarn in hot water. The results revealed facilitation of core extraction from the yarn body of the new 3-layer structure, which occurred due to rapid dissolution of the middle layer. The wicking behavior in the hollow yarn fabricated using the novel method followed the Locus Washburn equation and that of the hollow yarn produced from the core sheath yarn deviated from it. The results demonstrated that tensile properties of hollow nanofiber yarns were improved by increasing the thickness. Furthermore, hemolysis and cytotoxicity assays indicated that the fabricated hollow nanofibrous structure is non-toxic and blood compatible, indicating its potential for use in biomedical applications such as vascular scaffolds.     

Responses of cucumber plant to NH4 and NO3 nutrition: The relative addition rate technique vs. cultivation at constant nitrogen concentration

Different N sources (NO₃⁻, NH₄⁺, or NH₄NO₃) at different relative addition rates (RAR) were supplied to cucumber (Cucumis sativus L.), a species sensitive to NH₄⁺ toxicity. For comparison, cucumber plants were also grown at constant concentrations of 1 and 5 mM NH₄⁺ or 5 mM NO₃⁻. The fresh weight of NH₄⁺-fed plants at RAR 0.15 and RAR 0.25 day⁻¹ was similar to that of NO₃⁻-fed plants, while at RAR 0.35 or RAR 0.45 day⁻¹ growth reduction occurred. When available as a constant concentration, NH₄⁺ decreased plant growth at 5 mM. It is concluded that at low rates of N supply the relative addition rate technique can be used for growing cucumber plants with NH₄⁺ as sole N source without deleterious effects.     

Temperature-dependent development of <Emphasis Type="Italic">Diglyphus isaea</Emphasis> (Hymenoptera: Eulophidae) on <Emphasis Type="Italic">Liriomyza sativae</Emphasis> (Diptera: Agromyzidae) on cucumber

The development of Diglyphus isaea (Walker), a parasitoid of leafminers, was studied under laboratory conditions at seven constant temperatures (10, 15, 20, 25, 30, 35, and 40°C) on Liriomyza sativae Blanchard reared on cucumber (Cucumis sativus L.). The total development period (oviposition to adult emergence) decreased with increasing temperature between 15 and 35°C. In 10 and 40°C no development rate was found in D. isaea, so that it may be claimed that these temperatures fall outside the temperature range for development. Linear regression was used to describe the relationship between development rate and temperature. For egg to adult development, males of D. isaea required 153.8 degree-days (DD) above the theoretical threshold of 9.2°C and females required 161.3 DD above 9.4°C. Data were fitted to four nonlinear temperature-dependent models. Evaluation of the models took place based on the following criteria: fit to data, number and biological value of the fitted coefficient, and accuracy on the estimation of the thresholds. It could be concluded that the Briere-1 and Briere-2 models are suitable for estimating the minimum, maximum and optimal temperature thresholds of D. isaea. Thermal requirements and temperature thresholds can be used to predict the occurrence, number of generations and population dynamics of D. isaea.