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The effect of forest roads on the extent and type of fire damage occurred in forests and rangelands of the Neka County in Mazandaran province was investigated. For this purpose, all fire spots, stand number, percentage and type of injury and damage to tree species, and average diameter at breast height (DBH) were noted with 100% inventory; area and geographic location of access roads were determined using GPS. The results showed that distance from the main access road had a significant correlation with the area of ​​fire spots, but no significant correlation existed between the distance from the strip roads, skid ways, town of Neka and the area of ​​fire spots. The factors influencing fire severity were analyzed using the stepwise regression model. Model also showed that just the distance from the main access road affected the area of ​​fire spots. For every one meter increase in the distance from the main access roads, the area of fire spot was increased by 1.545 m². Further, the extent of fire can be controlled by reducing the distance from the main access roads.

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 Take-all is a devastating soil-borne disease of wheat Triticum aestivum L. The disease is caused by the pathogenic fungus Gaeumannomyces tritici, a pathogen distributed worldwide in major wheat production areas that causes severe damage to wheat production. Identification of genotypes with the high nutritional value of seeds can be considered in controlling this disease and in wheat breeding programs. Variation of high molecular weight glutenin subunits (HMW-GS) at the Glu-A1, Glu-B1, and Glu-D1 loci was studied using SDS-PAGE electrophoresis in 15 genotypes of bread wheat. A positive correlation was found between 1000-seed weight and the 5 + 10 allele (r = 0.594), indicating that presence of this allele will increase 1000-seed weight. A simple corresponding analysis was conducted to show the relationship between the take-all index and the genetic diversity of genotypes and the association between the bilateral groupings of individuals based on two criteria (genetic diversity and disease response). The result of stepwise regression showed that glutenin subunit null, 7 + 8, 2*, 7 + 9, 5 + 10 have linkage with resistance to take-all disease. Findings are useful in breeding programs to improve baking quality, develop uniformity and improve heterogeneous genotypes by selecting the best genotypes.

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ABSTRACT Rosa damascena has attracted considerable attention in horticulture, biochemistry and in pharmacology because of the fragrance of the flowers and the high content of its bio-logically active substances. There is limited information available on factors controlling flower yield and its components. The present study reports an investigation on flower yield and the various factors affecting it, in Iranian Rosa damascena using sixteen geno-types collected from different regions in Iran. These genotypes were planted at Isfahan Agriculture Research Center, using a randomized complete block design with three repli-cations in 2005. Twelve yield determining characters including flower yield per plant, number of flowers per plant, fresh flower weight, plant height, canopy diameter, length and width of bud, number of petal per flower, length and width of receptacle, fresh weight of petal as well as flowering period were recorded. Rosa damascena genotypes sig-nificantly varied for all the traits except for the fresh weight of petals per flower. Pheno-typic and genotypic coefficients of variation for flower yield per plant (48.03%, 36.49%), number of flowers per plant (40.65%, 26.99%), number of petals per flower (37.56%, 32.31%) were higher than the coefficients for other tested traits. Cluster analysis revealed that Khuzestan and Shiraz 2 genotypes were the most related ones, while the most inde-pendent ones were the western and eastern Azerbaijan genotypes. Results of stepwise re-gression analysis showed that 90 percent of total variation of flower yield per plant could be explained by the number of flowers per plant. This suggested that number of flowers per plant is the most important component determining flower yield per plant. According to principle component analysis, parents with a high standing of the following traits: fresh weight of flower, number of petals per flower and bud width, may well be employed for hybridization in a breeding program. Regression and cluster analyses proved to be the appropriate multivariate analyses for an identification of Rosa damascena genotypes pos-sessing the desirable characters for hybridization to develop improved cultivars.

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This study was conducted to investigate the response of four barley cultivars (Reyhan03, Yousef, Afzal, and Khatam) to salinity stress at 0 (control), 100, 200 and 300 mM levels as a factorial experiment, within the randomized complete block design in three replications in a greenhouse, using the Hoagland solution. The physiological and biochemical properties including dry weight and RWC, photosynthesis pigments, K⁺/Na⁺, osmotic adjustments (soluble sugars, glycine betaine, proline), hydrogen peroxide and antioxidants enzymes (catalase and peroxidase) in root and shoot of barley cultivars were evaluated in saline and non-saline conditions. To determine the relationship between growth performance and the physiological and biochemical properties, the correlation between the properties and causality analysis was examined. Results obtained from comparing the mean among the treatment combinations showed that the salinity stress reduced the dry weight, photosynthesis pigments, and K⁺/Na⁺, while it increased the soluble sugars, glycine betaine, proline, H₂O₂, catalase and peroxidase in the root and shoot of barley cultivars. Correlation analysis indicated that potassium in the shoot had the most positive and significant correlation coefficient (r= 0.86) with the dry matter of shoot. The stepwise regression analysis showed that the root dry weight, catalase of root and shoot, H₂O₂ of shoot and K⁺/Na⁺ of shoot contributed to the performance. Causality analysis revealed that the root dry weight, K⁺/Na⁺ of shoot, and catalase of shoot were highly important as they had a direct positive and significant impacts on the performance of shoot dry matter.