Mycorrhizal and non- mycorrhizal bean plants (phaseulus vulgaris) were treated with 100 ml solution containing 20 and 40 mM NaCl at three days interval in a pot culture experiment. The results showed decline in root infection by VAM as salinity accumulates. Sugar and protein content in mycorrhizal plants were significantly higher than those in treatments. Prolin and chlorophyll b content were not affected by salinity and mycorrhiza. At low and medium level of salinity K, Ca and P concentration were higher and Na concentration was lower in mycorrhizal plants. Results are discussed with respect to the role of VAM on diminishing the salinityeffects on plants.

Common bean belongs to Fabaceae and the subfamily of Lotoideae. It is the most important species of the grain family with noticeable economic importance in human's nutrition. Regeneration from tissue culture is one of the most suitable and effective procedures for preservation and reproduction of the plants. In this investigation, induction of callus, shoot and root has been studied in common bean (Phaseolus vulgaris L. cv. Goli) under different concentrations of a-Naphthalene acetic acid and Benzyl amino purine. First, the seeds were surface sterilized and transferred to suitable medium to achieve sterile seedlings. After 10 days, explants (hypocotyl, root and leaf) from sterile seedlings were tested in 25 various hormone treatments. For induction of organogenesis, explants were transferred to solid Morashige and Skoog medium supplemented with 30 g/lit sucrose, B5 vitamins and different concentrations of a-Naphthalene acetic acid (0, 0.1, 0.2, 0.4 and 0.8 mg/lit) and Benzyl amino purine (0, 0.5, 1, 2 and 4 mg/lit). Our data showed callus induction achieved in combination of two hormons: (0.4 mg/lit a-Naphthalene acetic acid and 2 mg/lit Benzyl amino purine). Induction of shoot increased with increasing concentrations of Benzyl amino purine to 2 mg/lit and then decreased. Induction of roots increased with increasing a-Naphthalene acetic acid concentrations. Furthermore, the level of internal auxin in common bean was high because the explants rooted in the minimum concentration of a-Naphthalene acetic acid. Subsequently, complete seedlings were transferred to the soil for further investigations.

Introduction Pulses are the second important for human diet. Pulses planting in agriculture systems had multiple outputs. In addition to their food importance for human and livestock, these plants play an important role in soil fertility. Growth and yield of French bean are substantially reduced by weed competition for nutrients, water and light. Application of pre emergence herbicides is quite common for weed control and it is often associated with post-emergence herbicide treatments. Alternatively, French bean growers rely on machine hoeing techniques, especially in organic farming systems. These techniques are often expensive, time consuming but they are not often successful or cost effective. The Critical Period of Weed Competition (CPWC) is a key consideration for IWMS programs and for the development of alternative weed management strategies. By definition, the critical period of crop growth cycle is length of time during which weeds must be controlled to prevent the unacceptable yield losses. The results showed that the bean is vulnerable to weeds, and weed control in bean production is the main problems in many countries, including Iran. The objectives of this study were to determine the CPWC in French bean, to gather specific information on the competition effects of weeds to this crop, and to understand the time during which yield-reducing competition occurs. Materials & Methods Field experiments were conducted in 2009-2010 at Azad University Shoushtar Branch Agricultural Research Station (32o 15′ N, 48o 28′ E). The soil was as: 42% clay, 51% silt and 7% sand, pH=7. 8, total organic matter 0. 4%, and a height of 84 meters above sea level. The soil was prepared according to the local practice for French bean production. Primary tillage consisted of spring chisel plugging and it was followed by two harrowing. The trials were preceded by wheat (Triticum aestivum L. ). French bean was sown at 40 seeds m-2 with the rows spaced 0. 9 m apart and at a depth of 4 cm. A randomized complete block design with 3 replicates was used for all trials. Individual plots consisted of 5 rows of French bean plants, each 4 m long. In order to determine the critical period of weed removal, the duration of tolerated competition (DTC) and weed-free period (WFP) were calculated. In order to determine the DTC, plots were left weedy for 12, 24, 36, 48, 60, 72 and 84 days after emergence (DAE) corresponding with 2-6, 6-10, 10-14, 14-18, 18-22 leaves, 50% flowering and 50% pod production respectively and weed free for the rest of the growing period. To determine the WFP, plots were kept weed-free for 12, 24, 36, 48, 60, 72 and 84 DAE and weedy for the rest of the growing period. The treatments were compared with two control plots kept weed-free and weedinfested throughout the crop cycle, respectively. We used MSTAT-C software to variance analyze of data. In addition, we used Duncan test to compare mean. Results & Discussion In this research, among wide leaf weeds Physali divaricat and Amaranthus viridis has the highest density. Narrow leaf weeds included Cyperus rotundus and Echinochloa crus-galli that Cyperus rotundus had the highest number. With prolongation of interference period of weeds the number of weeds primarily showed an increasing trend, and then decreased. In interference treatments the population of broad and narrow leaves reached the highest value i. e. 45 and 49 plant m-2 respectively 48 days after germination of French bean (14-18 leaves stage). After that their population decreased. Finally, their density respectively reached to 26 and 28 plant m-2 at harvest stage (Tables 1 and 2). The impact of interference and interference free treatments on dry weight of broad and narrow leaf weeds was significant (Table 3). With increase of competition period interference length treatments, dry weight of weeds increased such that the highest value of aggregated dry matter in broad leaves in throughout season interference treatment was 426. 7 gm-2, and in narrow leaves was related to interference treatment up to 72 days after germination of French bean (50% flowering) that reached 78. 3 gm-2. Dry weight of broad leaves in interference treatments was higher than narrow leaves (Table 8). With the closure of crop canopy a significant reduction occurred in density and biomass of narrow-leaf weeds. The results showed that the impact of weed interference and weed free period treatments on the performance of green pod and biological yield of French bean is significant at 1% probability level (Table 4). The comparison of green pod yield means of French bean showed that interference treatments significantly decreased the yield so that the lowest yield of green pod was seen in interference treatment up to 84 days. Its value was 349. 8 gm-2 that were located in the same statistical group with complete interference. In weed free period treatments, the highest value of yield was related to control treatment up to 84 days after germination that was 1959. 4 gm-2, and was located in the same statistical group with complete weed free treatment. Decreasing trend of pod yield can be attributed to weeds shade, flowers fall due to the presence of competition and more allocation of photosynthesis materials to growth. Therefore, French bean yield was decreased by increasing interference periods of weeds (Table 8). According to our research, the critical period for weeds control in French bean was determined 58 and 72 days after germination for acceptable reduction yield of 5% and 10%, respectively. Conclusion The results revealed the sensitivity of French bean in competition with weeds. Cultivation of beans requires correct implementation of weeds control operation particularly before planting and germination.

Introduction There are many different factors that affect yield and quality of agricultural crops, including weed management. The abundance, distribution, density and composition of weed species in a cropped field varies due to the nature of the crop, cultural practices and cropping pattern/system, soil type, moisture availability, location and season, therefore identification of weed flora is important to identify the proper weed control options and enables farmers to use the best management strategies. Common Bean (Phaseolus vulgaris L. ) is an increasingly important cash crop for growers in western provinces of Iran. Due to the lack of basic information about the weed diversity in common bean fields in Lorestan province which is the mean producer of bean in Iran), the current study was conducted for exact identification of flora condition of weeds. Materials & Methods The present investigation was carried out to find out weed floristic composition in common bean fields of Azna (33° 45΄ N latitude, 49° 45΄ E longitude, with a mean altitude of 1871 m above sea level), in the North of Lorestan province during 2014. In this study, 34 fields of bean using method of stratified random-sampling, and by assigning the suitable number of the samples for each level, were selected. The longitude and latitude and sea level of different fields were recorded exactly by global positioning system (GPS). In order to determine the density and composition of weeds, sampling in each field done using the pattern of W. According to the pattern of the W, 9 points in each field were selected and the distance between two sampling points was 20 meters and in each point by using a 0. 5 m × 0. 5m quadrate the density and composition of weed species was determined. For data analysis of weed flora in the fields, frequency, abundance index, distribution uniformity and mean density were calculated using appropriate equations. Weed frequency indicates the proportion of fields where the species was found. The diversity of weed species was described by species richness and weed density was determined by counting the number of plants in each sampling quadrate. Cluster analysis was done by JMP software using the data related to species richness index, species diversity and similarity. Results & Discussion In the current experiment, 23 weed species from 14 families were collected and identified at the different bean fields in the studied region. The highest number of weed species belongs to Poaceae family (five species) and Asteraceae family (three species). Based on results, 78% and 22% of weed species were dicotyledonous and monocotyledon respectively. Among the identified weed about 65% were annual and the remaining species were biennial or perennial. It seems that intensive and high input cultivation of common bean in the studied region affected the composition and diversity and density of weeds. Previous studies also showed that perennial weed communities under less cultivation and reduced tillage systems are often more frequent whearase in conventional systems the annual weed are dominant. Kenaf (Hibiscus cannabinus L. ), Field Bindweed (Convolvulus arvensis) and Redroot Pigweed (Amaranthus retroflexus L. ) had the highest and Black Nightshade (Solanum nigrum L. ) and Goat's Beard (Tragopogon pratensis L. ) had the lowest density, uniformity and abundance in the common bean fields. The density of the weed species varied considerably in the different fields and the maximum density of weed (5. 5 plants. m2) in the fields was recorded for Hibiscus trionum. The most important noxious weed of studied regions were Field Bindweed (Convolvulus arvensis), (Sorghum halepense (L. ) Pers. )، (Cynodon dactylon (L. ) Pers. ) and (Echinochloa crus-galli (L. ) Beauv. ). The highest value of species richness index (27. 5) and Simpsons diversity index (0. 94) were recorded for Southwest, whereas the lowest value of species richness index (17. 14) and Simpsons diversity index (0. 86) calculated for Southeast regions. Results of another study showed that species richness is related to geographical condition and increase with the height. Decrease of species richness in plain areas suggests that agronomic management has a strong effect on species diversity and weed abundance during the time. Conclusion The occurrence of numerous weed species in bean fields means that different methods of weed control must be selected because some of these weeds such as redroot pigweed (Amaranthus retroflexus L. ) can produce a lot of small seed which may increase the problem of weeds in further years. The higher number of dicotyledonous weeds means that special cautions for the use of chemical herbicides is necessary because many of recommended herbicides for broadleaf weeds could result in serious damages to the common bean fields. It seems that in these conditions considering the integrated weed management (IWM) methods is justified.