Iranian Journal Pulses Research

Abstract Introduction
Among three market class of bean (Phaseolus vulgaris L.) landrace in Guilan province, black streaked (Ojo de Cabra) has the highest cultivated area. This type of bean is a determinate bush with purple flowers, kidney-shaped seeds coated with black streaks in creamy background and hundred seed weight of 37 g. The great yield loss of bean posed by weeds represents the importance of planning effective weed control programs. With respect to increasing environmental concerns, if crop suppressive ability could be integrated into a weed management strategy, then the potential for improved weed control and reduced herbicide inputs would be promising. Every agronomic practices aim to improve germination extent, evenness and rate, seedling emergence and establishment, and plant growth and development for crop rather than weeds, would lead to enhance competitiveness of crop against weeds. Seed priming is a physiological technique in which seed hydration and drying occurs. Conventional methods of seed priming are hydro-priming, bio-priming, chemical priming, osmo-priming, nutrient priming, and priming with plant growth regulators. Seed priming due to promoting germination, emergence, and early growth of crop can ensure vigorous plants which may strongly compete with weeds. Therefore, priming could be expected to confer a competitive advantage on the crop. In this experiment, the possibility of utilizing priming in order to reduce the applied dose of two common bean herbicides, trifluralin and bentazone, were investigated.
 
Materials and Methods
In order to study the effect of seed pre-treatment with biological and chemical agents and herbicide application on growth and yield of dry bean landrace of black streaked (market class of Ojo de Cabra) as a common and widely used landrace in Guilan province, this field study was conducted at the University of Guilan in 2015. Treatments were arranged as a factorial with four seed pre-treatments and five weed management programs for a total of 20 treatments in a randomized complete block design with three replications. Seed pre-treatment consisted of priming by zinc sulphate and by salicylic acid, biopriming by Pseudomonas bacteria, and without priming. Weed management program included weed free (hand weeding), and weed infested condition, and 100, 75 and 50% recommended dose of trifluralin (Treflan, EC 48%, recommended dose of 960 g ai. ha^-1) and bentazon (Basagran, SL 48%, recommended dose of 960 g ai. ha^-1). To study the growth and development of bean, five stages of samples were taken. first destructive samplings were done at 16 days after planting and repeated every 14 days up to the last sampling was done at 72 days after planting (samples were taken 16, 30, 44, 58 and 72 days after planting). At each sampling, plant height, Leaf area and dry weight, and stem and total dry weight of bean plants were measured. Number and weight of pods, and biological yield were also determined at the last (5th) sampling time. Data were subjected to ANOVA, using SAS v. 9.2. Means were separated using Fisher’s Protected LSD test at the 0.05 level of significance.
 
Results and Discussion
The height of bean plants was higher by 11% in priming by salicylic acid compared to non-priming treatments. Seed biopriming by Pseudomonas bacteria compared to non-priming treatment increased the maximum leaf area index, maximum leaf dry weight, total dry weight, number of pods per square meter, and biological yield by 30, 69, 50, 31, and 50%, respectively. Weed management also affected crop production. The highest amounts of the measured traits were recorded for treatments of weed free condition and recommended dose of herbicides. The values of measured traits reduced as herbicide dose decreased. Full-season weed infested condition compared to weed free condition reduced the maximum leaf area index, maximum leaf dry weight, total dry weight, number and weight of pods per square meter, and biological yield by 40, 58, 58, 72, 70, and 58%, respectively. The lowest values belonged to weed infested condition. The effect of reduced rate application of 75% of the recommended dose of trifluralin and bentazon were not significantly different from recommended dose of two herbicides for all traits in all sampling times, except the stem dry weight in third sampling, and pod numbers per square meter. Therefor it seems possible to apply reduced dose of recommended herbicides while minimizing weed competitive effects and maintaining economic returns of bean production. This also would decline undesirable effects accompanied by herbicide application including herbicide-resistant weed populations that challenge sustainability of weed management programs.
 
Conclusion
However, non-significant interaction of seed pre-treatment and herbicide application revealed that despite seed priming methods was positively correlated with growth, development and production of bean, but not with competitiveness of the crop, and thus could not provide a reliable management strategy to reduced herbicide inputs. Generally, since implementation of integrated weed management systems are of fundamental importance in modern weed control, more attention should be given to the possibility of setting up weed control programs involving herbicides reduced dose application combined with crop competitive ability.

Abstract Introduction
Chickpea provides N benefit to cereals grown in crop rotation. In addition to the N benefit, chickpea provides a disease break for wheat grown in the crop rotation. Imazethapyr, applied preemergence at the rate of 0.053 kg ai/ha, reduced plant height, delayed plant maturity, and caused leaf chlorosis. Imazethapyr, applied at 0.053 kg/ha, significantly reduced plant height compared with the nontreated or hand-weeded checks. Visual injury symptoms observed with Imazethapyr treatment included chlorosis and delayed maturity of chickpea. There was an apparent rate effect with imazethapyr, when this herbicide was applied at 0.026 kg/ha with sulfentrazone, visual injury symptoms were significantly reduced. The risk of crop injury from the higher use rate of Imazethapyr is probably not commercially acceptable, whereas the injury from the lower use rate probably is acceptable. Pre-emergence application of low-rate of imazethapyr caused minor levels of injury to the plants, it had only minor effects on plant development and yield compared with sulfentrazone. Post-emergence applications of imazethapyr, imazamox and metribuzin, delayed flowering and maturity and reduced yield. Herbicide effects varied with chickpea cultivar. Most of the commonly used herbicides that are recommended for wheat fields weed control are not able to fully control the wild barley (Hordeum spontaneum C. Koch) weed. Hence, utilizing appropriate agronomic strategies for managing this weed is critical. The evaluation of the effect of Wild barley spike cut-off on the previous wheat field, and the effects of chickpea sowing date and weed control measurements in chickpea cultivation in the next year in crop rotation on chickpea yield are among the aims of this study.
 
Materials and Methods
The effect of wild barley weed spike cut off in wheat crop and sowing date and management strategies in chickpea cultivation on chickpea yield in the following year was evaluated in Khorramabad, Lorestan, during 2008-2009 and 2009-2010. The experiment was factorial split plot based on completely randomized block design with three replications. The factorial of the wild barley weed spike cut off in wheat (in two levels: 1- No spike cut off, and 2- Spike cut off) and chickpea sowing date in the following season (in two levels: 1- early sowing and 2- late sowing) was assigned to main plots, and the weed management factor levels in chickpea cultivation at five levels: 1- Pre emergence application of Metribuzin (0.7 kg/ha from Sencor 75%), 2- Pre emergence application of Imazethapyr (0.7 L/ha from Pursuit 10%), 3- Post emergence application of Clethodim (1 L/ha from Select 12%), 4- Hand weeding, and 5- Weedy check was assigned to sub plots.
 
Results and Discussion
Wild barley weed spike cut off in wheat in previous year increased the average grain yield of chickpea by 26.5%. Chickpea grain yield for early sowing was 49.9% higher than late sowing. Pre emergence application of Imazethapyr (0.7 L/ha) and Metribuzin (0.7 kg/ha) had a persistence phytotoxic effect on chickpea. Reducing plant height, leaf brushing, increase the number of branches and delay in reproductive phase, were the negative effects of Imazethapyr herbicide on chickpea. Weed interference in early and late chickpea sowing date significantly reduced 17.8% and 49.8% of chickpea grain yield, respectively. The highest grain yield of chickpea (2309 kg.ha^-1) was observed in hand weeding treatment in early chickpea sowing under Wild barley Weed spike cut off in wheat crop conditions, and the lowest chickpea grain yield (449.3 kg.ha^-1) was associated to Imazethapyr herbicide application in the late sowing chickpea with under Weed No spike cut off Wild barley in wheat crop in previous season.
 
Conclusions
The results of this study showed that with the spike cut off wild barley weed in the previous wheat cultivation and preventing current year weed seed rain, we can greatly reduce the population of this grass weed in chickpea cultivation in the following year and consequently reduce its interference effects on chickpea. Chickpea early sowing was also effective in increasing the chickpea yield due to the high efficiency of sowing equipment in controlling wild barley plants and decreasing the population of this weed and, also due to synchrony of crop growth stages with better environmental conditions. In the case of herbicides tested, the Clethodim is an appropriate graminicide for controlling the wild barley in chickpea cultivation, which, of course, achieving a good control requires application in the early stages of grass weeds, and the delay in spraying reduces the control efficiency of this herbicide.

Abstract Introduction Weeds have significant negative effects on agricultural ecosystems. They are responsible for the decline of crop yield because of competition with crops for water, nutrients and sunlight. Existing weed control methods are either expensive or hazardous. Heavy use of chemical herbicides in most integrated weed management systems is a major concern since it causes serious threats to the environment, public health and increase cost of crop production. Therefore, alternative strategies against weed must be developed. Allelopathy is defined as the inhibitory/stimulatory effect(s) of one plant on other plants through the release of chemical compounds into the surrounding environment. It is characterized by a reduction in plant emergence or growth, reducing their performance in the association. Allelopathy provides a relatively cheaper and environmental friendly weed control alternative. This can be considered as a possible alternative weed management strategy. A number of plants have also been known to exhibit allelopathic property on other plants. Allelopathy associated with plants due to the presence of allelochemicals such as monoterpences, phenolic and volatile compounds in their foliage. Therefore, the present study was done to develop management practices to reduce the use of agro-chemicals for sustainable agriculture. Therefore, the effects of allelopathic potential of sugar beet and canola on suppression of some weeds of chickpea farm were studied.   Material & Methods A field experiment based on a randomized complete block design with four replications was carried out in a naturally weeds infested land to investigate the allelopatic effects of canola (Brassica napus L. var Ocapi) and sugar beet (Beta vulgaris Var Jolge) residues on weeds and yield of chickpea (Cicer arietinum) at research center of Shirvan Agricultural College (37° 23¢ north latitude and 57° 54¢ east longitude and altitude of 1060 meters), North Khorasan Province, Iran. Seven treatments including I: chopped residues of canola (1.5 kg m^-2), II: chopped residues of sugar beet (1.5 kg m^-2) both were separately incorporated to 25 cm depth soil uniformly 20 days before sowing, III: chopped residues of canola and sugar beet mix together (0.75 kg/m² each), IV: shoot aqueous extract of canola, V: shoot aqueous extract of sugar beetVI: mixed adequate extract of canola & sugar beet, which were separately sprayed at post emergence stage (at 7, 15 and 30 days after sowing) and VII: without any residues and spraying as control. For preparation of aqueous extract, chopped shade dried residues of canola and sugar beet were separately ground into fine powder (using an electric mill). One hundred g of ground tissue of each of the tested species was placed in a 2 L Erlenmeyer flask and 1 L distilled water was added and left for 48 h at room temperature. The mixtures were then filtered through a double layer of cheese cloth followed by Whatman No.1 filter paper using a vacuum pump. Water extracts were applied between rows at the rate of 100 ml per square meter twice at 7 and 14 days after sowing (DAS) using a knapsack hand-sprayer fitted with a flat fan nozzle maintaining a pressure of 207 kpa.   Results & Discussion The result of experiment showed that growth traits of weeds and chickpea plant are significantly affedted by treatments. Maximum inhibition on weed density, weed dry weight, weed coverage (%) and the hight of chieckpea plants were recorded when using sugar beet residues incorporated with soil. So weed density, weed dry weight, weed coverage and the height of chickpea plants decreased by 52.4%, 90.15, 52.6% and 25.2%, respectively, compared to control.  The highest (329.4 g m^-2) and lowest (192.1 g m^-2) chickpea dry weight were obtained in shoot aqueous extract of canola and shoot aqueous extract of sugar beet, respectively. The highest harvest index (59.2%) observed in plants treated with sugar beet residues. Some studies reported that allelochemicals like salt and drought stresses exhibited inhibitory effects on physiological processes that translate to growth. The effects of allelopathy on germination and plant growth may occur through a variety of mechanisms including reduced mitotic activity in roots and shoots, suppressed hormone activity, reduced rate of nutrient uptake, inhibited photosynthesis and respiration, inhibited protein formation, decreased permeability of cell membranes and/or inhibition of enzyme action. Weed cover reduction can be closely linked to slower leaf production and development of smaller leaves. It was reported that at stress condition leaf area decreases due to a combination of a decrease in cell number and in cell size. A possible reason for dry matter reduction could be the greater reduction in uptake and utillisation of mineral nutrients by plant under allelochemical stress condition. Hegab et al, (2008) found that higher concentration of allelochemical induced inhibitory effect on amylase activity in wheat seedlings. They also reported the application of allelochemicals at high concentrations decreased protein content of wheat seedlings.   Conclusion The present study concludes that integrating canola and sugar beet residues has the potential to suppress weeds germination and growth. These residues can be used as an eco-friendly approach to manage weeds in chickpea fields.

Abstract Paraquat herbicide weed control efficacy in stale seedbed practices was evaluated by split plots arrangement according to a randomized complete block design with three replications in Lorestan province during 2009 and 2010. The common bean seed rate (in three levels: 100, 150 and 200 kg.ha-1) and weed management in seven levels (1. Trifluralin PPI; 2. Paraquat PRE; 3. Bentazon+acifluorfen POST; 4. Trifluralin PPI+ Bentazon+acifluorfen POST; 5. Paraquat PRE +Bentazon+acifluorfen POST; 6. Hand weeding; 7. Weedy check) were allocated to main plots and sub plots, respectively. In the first year, among the herbicide treatments, the lowest weed density was belonged to the paraquat PRE+Bentazon+acifluorfen POST, that reduced weed density by 68% in comparison to weedy check. Trifluralin PPI+ Bentazon+acifluorfen POST, Paraquat PRE +Bentazon+acifluorfen POST, and Bentazon+acifluorfen POST alone were reduced weed biomass 83, 82 and 70%, respectively. Based on the second year experimental results, all management treatments significantly reduced weed density compared to weedy check. Treatments included Trifluralin PPI, by average were reduced weed density 77% compared to weedy check. Integrated application of Paraquat PRE+Bentazon+acifluorfen POST, also reduced weed density by 55%, and had not significant differences with superior treatment.