Economic valuation and conservation: Do people vote for better preservation of Shadegan International Wetland?

Shadegan International Wetland (SIW) is a unique natural ecosystem with great national and international significance, designated under Ramsar Convention. Located in southern part of Iran, this wetland serves many functions. Among them the rich biodiversity, ecological, hydrological, and economic functions are the most important. Despite the great opportunities for sustainable development of this wetland, it is currently under serious threats from a diverse range of non-sustainable activities. Underestimating SIW’s non-market values in development decisions is a major reason for the conversion and excessive depletion of its resources. The aim of this study was therefore to estimate the economic benefit of SIW as a very useful instrument to reflect the values of this unique ecosystem to society members. A choice experiment (CE) survey was undertaken to estimate the value of different nonmarket attributes of SIW. In addition to the overall model, users and nonusers preferences were also estimated. Random parameter logit (RPL) model was employed to derive the marginal value of the respondents for different attributes of the nonmarket values of SIW. Results indicated the respondents’ positive preferences towards better conservation of SIW.     

Resistance spectra of wheat genotypes and virulence patterns of <Emphasis Type="Italic">Mycosphaerella graminicola</Emphasis> isolates in Iran

Co-evolution of wheat and its devastating pathogen Mycosphaerella graminicola (anamorph Septoria tritici), the causal agent of septoria tritici blotch, a foliar disease of wheat, is suggested to occur in Fertile Crescent as their center of origin and, thus, interaction between pathogen virulence and host resistance is important subject to be addressed. We have investigated resistance spectra of 54 wheat genotypes including a set of differentials carrying known resistance genes and virulence patterns of 14 M. graminicola isolates at seedling stage under controlled environmental conditions. The isolates were collected in Iran from five provinces. Diversity in virulence and aggressiveness was observed among the isolates from four provinces. Isolates collected from Golestan province were virulent to all wheat genotypes from germplasm of Iran, while specific resistances were identified to the isolates from other provinces. Among wheat genotypes, cvs. Chamran, Morvarid and Hirmand had the greatest number of specific resistances as well as partial resistance. Wheat genotypes of the differential set also differed in their reactions to the isolates. Arina, Flame and TE 9111 were specifically resistant to the greatest number of isolates from different provinces. Most isolates were virulent to the other differentials such as cvs. Shafir, Estanzuela federal and Courtot indicating that extensive adaption of virulence to most of the known resistance genes (Stb) has occurred in these regions. The new sources of resistance to highly virulent isolates from Iran may also be utilized in wheat breeding programs to develop resistant cultivars against pathogen populations in other countries.     

Inheritance of resistance to sunflower downy mildew races 1, 2 and 3 in cultivated sunflower

Sunflower downy mildew (SDM) caused by Plasmopara halstedii, is a major disease of sunflower. Eleven resistance genes have been identified, but allelic relationships among these genes are not clear. This study examined the inheritance and allelic relationships of genes conferring resistance to SDM races 1, 2 and 3 (virulence phenotypes 100, 300 and 700, respectively) and confirmed a twelfth resistance gene. Three USDA Plant Introductions, AMES 3235, PI 497250, and PI 497938, and three released lines, RHA 266, RHA 274 and DM‐2 were studied. RHA 266 has only the Pl₁ gene for race 1 resistance. Digenic inheritance of resistance was found in AMES 3235, PI 497250, and RHA 274. These lines have the Pl₁ and Pl₁₂ genes, conferring resistance to race 1, and the Pl₂ and Pl₁₁ genes, conferring resistance to race 2. DM‐2 and PI 497938 have Pl₁₂ (but not Pl₁ for resistance to race 1, the Pl₁₂ gene (but not the Pl₂) for resistance to race 2, and Pl₅ for resistance to race 3. These resistance genes will serve as a foundation for future gene designations and genetic diversity studies of resistance to SDM.     

Comparing the Soil Conservation Service model with new machine learning algorithms for predicting cumulative infiltration in semi-arid regions

Water infiltration into soil is an important process in hydrologic cycle; however, its measurement is difficult, time-consuming and costly. Empirical and physical models have been developed to predict cumulative infiltration (CI), but are often inaccurate. In this study, several novel standalone machine learning algorithms (M5Prime (M5P), decision stump (DS), and sequential minimal optimization (SMO)) and hybrid algorithms based on additive regression (AR) (i.e., AR-M5P, AR-DS, and AR-SMO) and weighted instance handler wrapper (WIHW) (i.e., WIHW-M5P, WIHW-DS, and WIHW-SMO) were developed for CI prediction. The Soil Conservation Service (SCS) model developed by the United States Department of Agriculture (USDA), one of the most popular empirical models to predict CI, was considered as a benchmark. Overall, 154 measurements of CI (explanatory/input variables) were taken from 16 sites in a semi-arid region of Iran (Illam and Lorestan provinces). Six input variable combinations were considered based on Pearson correlations between candidate model inputs (time of measuring and soil bulk density, moisture content, and sand, clay, and silt percentages) and CI. The dataset was divided into two subgroups at random:70% of the data were used for model building (training dataset) and the remaining 30% were used for model validation (testing dataset). The various models were evaluated using different graphical approaches (bar charts, scatter plots, violin plots, and Taylor diagrams) and quantitative measures (root mean square error (RMSE), mean absolute error (MAE), Nash-Sutcliffe efficiency (NSE), and percent bias (PBIAS)). Time of measuring had the highest correlation with CI in the study area. The best input combinations were different for different algorithms. The results showed that all hybrid algorithms enhanced the CI prediction accuracy compared to the standalone models. The AR-M5P model provided the most accurate CI predictions (RMSE=0.75 cm, MAE=0.59 cm, NSE=0.98), while the SCS model had the lowest performance (RMSE=4.77 cm, MAE=2.64 cm, NSE=0.23). The differences in RMSE between the best model (AR-M5P) and the second-best (WIHW-M5P) and worst (SCS) were 40% and 84%, respectively.     

籽棉团悬浮速度的理论算法与试验验证

针对常规悬浮速度理论值与测试值间的偏差大问题,该研究将以常规悬浮速度理论为基础,通过量纲分析法和力平衡原理,建立籽棉团物理属性与阻力系数之间的关系,提出一种轻软可压缩颗粒悬浮速度理论模型。然后,在棉田测试单颗棉桃完全开裂时所含籽棉团直径,确定气力输棉管道最小直径,并通过管流雷诺数和绕流雷诺数计算确定阻力系数。用体积法测试籽棉团密度并用等密变径法制备6种不同密度、18种不同直径的球形籽棉团试样并进行悬浮速度试验测试。结果表明,单颗棉桃全开裂时直径变化范围在38～54 mm之间,在这范围内管流和绕流雷诺数都大于500,阻力系数确定为0.44;籽棉团松散密度范围在21.2～35.3 kg/m3之间,半压实密度范围在101～137.4 kg/m3之间;籽棉团悬浮速度测试值从直径比大于0.6开始与常规悬浮速度理论值偏离,直径比等于1时籽棉团悬浮速度测试值不等于零。采用该研究提出的理论模型和计算方法时,所得到的籽棉团悬浮速度分布特征和大小与测试结果基本吻合,平均相对误差为4.6%,并通过方差分析验证了该研究提出的理论模型和计算方法的有效性。这为籽棉、羊毛和驼绒等轻软可压缩物料的气力输送系统和装置的改进设计提供理论模型和计算方法。     

Characterization of Lasiodiplodia species causing leaf blight,stem rot and fruit rot of fig (Ficus carica) in Malaysia

Fig (Ficus carica) is an exotic deciduous plant that is grown worldwide. Fungal diseases pose a major threat to fig plants, affecting their fruit quality and production. This study was conducted to characterize the fungal isolates associated with leaf blight, stem rot and fruit rot of F. carica in Malaysia through morphological analysis, DNA sequencing, multigene phylogenetic analysis and pathogenicity tests. From September 2018 to March 2019, 30 blighted leaves and 30 rotted stems and fruits of F. carica were collected from several nurseries in Malaysia. Thirty fungal isolates that belonged to Lasiodiplodia theobromae (27 isolates) and L. brasiliensis (three isolates) were identified based on morphological characteristics, comparison of DNA sequences and phylogenetic analysis of the internal transcribed spacer (ITS), elongation translation factor 1-α (tef1-α), β-tubulin (tub2) and DNA-directed RNA polymerase II subunit (rpb2). Among the 27 isolates of L. theobromae, nine isolates were obtained from leaves, eight isolates from stems and 10 isolates from fruits, whereas the three isolates of L. brasiliensis were obtained from stems (two isolates) and a leaf (one isolate). The results of pathogenicity tests revealed that L. theobromae and L. brasiliensis isolates were responsible for leaf blight and stem rot of F. carica, whereas fruit rot was caused by L. theobromae isolates. The present study highlighted two different species, L. theobromae and L. brasiliensis, as the causal agents of leaf blight and stem rot of F. carica. Additionally, L. theobromae caused fruit rot of F. carica in Malaysia.     

Development of a DNA vaccine against chicken anemia virus by using a bicistronic vector expressing VP1 and VP2 proteins of CAV

In the present study, we describe the development of a DNA vaccine against chicken anemia virus. The VP1 and VP2 genes of CAV were amplified and cloned into pBudCE4.1 to construct two DNA vaccines, namely, pBudVP1 and pBudVP2-VP1. In vitro and in vivo studies showed that co-expression of VP1 with VP2 are required to induce significant levels of antibody against CAV. Subsequently, the vaccines were tested in 2-week-old SPF chickens. Chickens immunized with the DNA-plasmid pBudVP2-VP1 showed positive neutralizing antibody titer against CAV. Furthermore, VP1-specific proliferation induction of splenocytes and also high serum levels of Th1 cytokines, IL-2 and IFN-γ were detected in the pBudVP2-VP1-vaccinated chickens. These results suggest that the recombinant DNA plasmid co-expressing VP1 and VP2 can be used as a potential DNA vaccine against CAV.     

Development of Molecular Tools for Distinguishing Between the Highly Similar Rx1 and Rx2 PVX Extreme Resistance Genes in Tetraploid Potato

The Rx1 and Rx2 are extreme resistance genes, which have been introgressed from different species into potato cultivars and breeding lines. These two genes have a 98% and 96% sequence similarity at the nucleotide as well as at the amino acid level, respectively. Except one extra amino acid in the Rx2 gene, the high variations of the amino acid chain are due to single and double nucleotide variations, which are scattered throughout the coding regions. The high level of sequence similarity makes it complicated to identify these genes and to distinguish them from other highly similar genes, like the Gpa2 or from paralogous sequences by a single polymerase chain reaction (PCR). Here, we report the development of markers for the simple and rapid identification of the Rx1 as well as the Rx2 gene. Further, a multiplex PCR reaction is recommended for the simultaneous detection of both genes in a single reaction. Since these genes reside on different chromosomes, following their inheritance by the multiplex PCR method could help the easy incorporation of both genes into breeding lines. The detection method shown here could be routinely used in marker-assisted selection for Potato virus X extreme resistance and could enhance the effectiveness of potato breeding programs. Besides potato breeding, this method could also be effectively applied to mapping experiments as well as in research studies of resistance.