جستجوی مقالات مرتبط با کلیدواژه « سرعت رشد » در نشریات گروه « زراعت »

Soybean (Glycine max L.) is one of the most important oilseeds in the world due to its 18 to 22% seed oil and high protein content (36-38%). Meanwhile drought stress is one of the important factor limiting its growth and yield. Drought stress limits root growth and reduces the mobility of important micro-nutrients especially zinc in the soil. Application of zinc sulfate fertilizer increases physiological growth parameters, grain yield and water use efficiency in soybeans. Also mycorrhizal colonization in plants increases growth, improves yield, and increases the plants resistance to drought stress. This study aims to evaluate the effect of mycorrhiza and zinc sulfate fertilizer application method on some soybean growth physiological indices and its water use efficiency under soil moisture deficit stress.

The experiment was performed as a factorial experiment in the form of randomized complete blocks with three replications. First factor was moisture stress at three levels of no-stress, mild stress and severe stress (irrigation after 60, 90 and 120 mm evaporation from Class A pan, respectively). Second factor was arbuscular mycorrhiza (Funneliformis mosseae) in two levels of application and no-application and third factor was the application method of zinc sulfate fertilizer in three levels of no-application, soil application and foliar feeding. To evaluate the response of growth indices of soybean, plant samples were prepared during the growing season and their leaf area and dry matter were measured. Water use efficiency was also obtained from the ratio of grain yield to the volume of water consumed. During flowering stage, the percentage of mycorrhiza colonization was measured and grain yield was obtained by harvesting two square meters from each plot.

In this experiment, severe moisture stress shortened the growth period of soybeans. The results showed that at all levels of moisture stress, inoculation with mycorrhiza increased leaf area index, crop growth rate, water use efficiency and grain yield. Application of mycorrhiza and foliar feeding of zinc sulfate increased maximum leaf area index, maximum crop growth rate and water use efficiency by 69, 98 and 112%, respectively. In the absence of mycorrhiza, soil application of zinc sulfate had no effect on maximum leaf area index and maximum crop growth rate, but the use of mycorrhiza led to a 15 and 20% increase in these indices by soil application of zinc sulfate compared to no zinc sulfate use. Severe and moderate moisture stresses in no-application of mycorrhiza and no zinc sulfate reduced the total dry matter by 47.22 and 63.04%, respectively, but the application of mycorrhiza in these treatments has reduced the severity of these effects and led to increase of 111.20% in total dry matter. The highest colonization of mycorrhiza occured in moderate moisture stress (65.33%). Soil application of zinc sulfate reduced the colonization of mycorrhiza even compared to the no-application of zinc sulfate fertilizer. In this study, the highest percentages of mycorrhizal colonization occured in moderate moisture stress and foliar application of zinc sulfate by 64 and 59%, respectively. Foliar feeding of zinc sulfate compared to no-zinc sulfate, under severe moisture stress increased grain yield by 68% (1100 kg ha-1). No-application of mycorrhiza led to no difference between soil use and no-application of zinc sulfate in soybean yield. Mycorrhiza in no-moisture stress, moderate stress and severe stress increased water use efficiency by 80.49, 183.33, 275% respectively, compared to no-application of mycorrhiza.

According to the results, foliar feeding of zinc sulfate is more efficient than soil application of zinc sulfate, but this efficiency decreases during moisture stress. Application of mycorrhiza in addition to reducing the effects of moisture stress can increase the efficiency of zinc sulfate fertilizer especially under foliar feeding conditions.

In some olive trees despite suitable vegetative growth and reproductive to maturity stage, fruits do not set and development do not occur, due mainly to lack of the adaptability. This research was conducted to determine the optimal time for topworking in olive trees using scions from two common cultivars in each of the six provinces including Fars, Khuzestan, Kermanshah, Lorestan, Ilam and Qazvin in Iran during 2021-2022. Results showed that optimal time for topworking in olive trees in Khuzestan was in the mid-October with cv. Conservolia scion, in Ilam in the second half of October with cv. Conservolia and cv. Diereh scions, in Lorestan in the first half of October with cv. Amygdalia scion, in Fars in the first half of October with cv. Consevolia scion, in Kermanshah in September with cv. Conservolia scion, in Qazvin on May 20th with cv. Conservolia scion.

In some olive trees despite suitable vegetative growth and reaching to maturity stage, fruits does not set and development do not occur, due mainly to lack of the adaptability (Hartman et al., 2017). Topworking has been practiced, for long-time, in some fruit trees such as pecan (Yates and Sparks, 1992) and walnut (Rezaee and Vahdati, 2008). Sometime in a region, a fruit tree variety is planted without assessment of its adaptability and quality properties. Therefore, its performance is not satisfactory and economically profitable. Therefore, changing the variety is necessary. In such a case, topworking-using scions from adapted and high yielding with desirable fruit and oil quality is a strategy to save farmer’s investments. It has been demonstrated that topworking in different olive varieties resulted in better vegetative growth and fruit yield. However, it differed with rootstock variety (Lion et al., 2020). In recent decades olive orchards in Khuzestan and Fras provinces in Iran has been established using olive varieties that are not well adapted and produce low yield with low quality (Ajamgard and Zeinanloo, 2013; Taslimpour, et al., 2016). To change the variety of olive orchard, olive producers should bear high costs. Therefore, topworking can help to graft scions from adapted high yield varieties on the rootstock of existing orchards. The main objective of this research was to determine the optimal time for topworking in olive trees in different regions of Iran, and to recommend the optimal time and suitable scion cultivars for each region. 

The experiments were carried out, during 2021 and 2022, as split-plot arrangements in completely randomized design with three replications. Grafting dates at five levels from Auguest 29th to November 28th (in Qazvin from May) were assigned to main plots, and olive cultivar at two levels (cv. Conservolia was common + one adapted cultivar in each location) were randomized in sub-plots. The grafting success rate and the scion growth were evaluated and recorded. Analysis of variance for data was performed using SAS 9.4 software. Duncan’s Multiple Range Test was employed for means comparsion at the 5% and 1% probability levels. 

The results showed that in Khuzestan province the mid-October was the optimal date for topworking of olive trees. Also cv. Conservolia’s scions had significantly (P ≤ 0.01) greater growth than cv. Avan scions. In Ilam province, the results showed that the maximum grafting success rate achieved in the second half of October with cv. Conservolia nd cv. Diereh scions. In Lorestan province, the grafting success rate, using scions of cv. Conservolia and cv. Amygdalolia were 88% and 80%, respectively, in the first half of October. In Fars province, the success of topworking in the first half of October was 80%, while the vegetative growth of cv. Conservolia’s scion was greater than cv. Amygdalolia. In Kermanshah province, the results showed that the grafting success rate of olive trees was significantly (P≤ 0.05) higher in September with cv. Consevolia scion. In Qazvin province, the results showed that the optimal date for topworking of olive trees was May 20th with grafting success rate of 75% and 94% for cv. Conservolia and cv. Zard, respectively. Hussain et al. (2021) reported that topworking in olive trees in Pakistan was more successful in June-July. Yates and Sparks (1992) and Rezaee and Vahdati (2008) also reported that topworking improved yield and quality of pecan and walnut, respectively.The highlight of the results of this research was determination of optimal time (optimal window) and suitable cultivars (scions) for topworking in olive trees in the six target regions in Iran. 

Rootstocks can affect the reaction of the grafted trees to water stress by controlling vegetative growth and nutrients uptake and studying morpho-physiological and nutritional mechanisms and responses of the rootstocks submitted to drought stress would make it feasible to select the tolerant rootstocks. For this purpose, to investigate the effects of drought stress on some clonal Prunus sp. rootstocks, an experiment, in completely randomized design was conducted in a greenhouse in Saman (Sharekord) and Shahrekord University laboratories in 2017-2018.

Rooted cuttings of Cadaman, Myrobalan29c, GF677 and GN15 were planted and maintained under greenhouse conditions employing regular practices including irrigation and nutrients supplementation and pest management for three months. Plants were submitted to drought stress at three levels including 100, 75 and 50% of field capacity for 40 days. Plant height, dry weight, relative water content, water use efficiency, electrolyte leakage and mineral content (P, K+, Ca2+, Mg2+, Fe2+ and Zn2+) in leaves and roots were assessed.

The results showed that the total dry weight was significantly decreased under the influence of drought stress. Leaf moisture content and specific leaf weight (SLW) decreased but leaf area ratio (LAR) and specific leaf area (SLA) increased under water deficit condition. Also, due to the drought stress, the greatest decrease in growth rate occurred in Cadaman and Myrobalan29c rootstocks, but no significant changes were observed for GN15 rootstock. Under drought stress conditions, relative water content (RWC) of the leaves decreased, while electrolyte leakage (EL) increased, with the highest figures observed for Myrobalan29c. With the increasing intensity of drought stress, water use efficiency (WUE) decreased for the Cadaman rootstock, but it was increased for GF677 and GN15 rootstocks. While no significant changes were observed for Myrobalan29c rootstock. Drought stress reduced the mineral contents (P, K+, Ca2+ and Mg2+) in the roots and leaves of the rootstocks. The highest decrease in concentrations of elements such as K+, Ca2+, P and Fe2+ were found for Myrobalan29c and Cadaman rootstocks.

All the tested rootstocks were significantly affected by drought stress, including growth retardation, but they resisted to drought stress at different levels and by varying mechanisms. So that some rootstocks with better use of available water and more nutrients absorption efficiency, showed a greater ability to maintain their biological activities in the face of dehydration. Other rootstocks showed poorer performance against drought stress and underwent damages compared to other rootstocks.

Delayed planting of sugar beet, use of nitrogen fertilizer and growth promoting bacteria are important in accelerating growth and compensating time loss. To study this subject, a split split plot experiment was conducted in a randomized complete block design with 3 replications and 8 treatments in 2018 at the Research Farm of Ferdowsi University of Mashhad. The factors under study consisted of planting date with two levels (regular planting, D1, and delayed planting, D2) as the main factor, nitrogen fertilizer with two levels (use of nitrogen fertilizer based on recommended rate, N1 and 25% less than recommended rate, N2) as a subfactors and bacterial growth stimulant with two levels (bacterial inoculation, B2, and without its use, B1) were considered as sub-sub- factors. Growth indices under study were leaf area index, total dry matter, crop growth rate, relative growth rate and net assimilation rate. In this study, highest leaf area index (3.5) and dry matter accumulation (2898 g.m-2) in thermal unit, as well as growth rate, relative growth rate and net assimilation rate under regular and delayed planting dates were due to the use of recommended rate of nitrogen fertilizer and bacterial inoculation treatments. The least amounts of these traits were obtained at both planting dates and use of nitrogen fertilizer, 25% less than the recommendation, and without using bacteria. Root yield and sugar content sugar beet under treatment of bacterial and nitrogen use, based on recommended rate, showed 8 to 10% higher than other treatments, under both regular and delayed planting date. It seems that the combined use of chemical and biological fertilizers is useful in delayed sowing, to compensate delayed time loss planting of sugar beet.

Nitrogen and phosphorus are essential nutrients in growth of plants. In addition, the type and method of fertilizer application play an important role in the efficient absorption of nutrients and reduce fertilizer use. Therefore, an experiment was conducted in a randomized complete block design with three replications in the Bahar city in 2017: phosphorus fertilizer was three levels (no application, triple superphosphate and diammonium phosphate), nitrogen fertilizer with two levels (placement and no-placement) and potato cultivar with three levels (Agria, Banba and Sante). The highest leaf area index (5.27), crop growth rate (13.22 g.m-2) and total dry matter (582.86 g.m-2) were obtained from diammonium phosphate along with nitrogen placement in by using Agria cultivar. The results also showed that under conditions phosphorus deficiency, nitrogen application method did not affect leaf area index, crop growth rate and total dry matter: However, tuber yield of Agria under phosphorus deficiency increased by nitrogen placement treatment. In this study, the use of diammonium phosphate, compared to triple superphosphate, increased leaf area index, crop growth rate, relative growth rate and total dry matter. The effect of nitrogen placement along with triple superphosphate was higher than that of nitrogen with diammonium phosphate. Chlorophyll index was not affected by nitrogen placement when using diammonium phosphate, whereas, nitrogen placement increased chlorophyll index by 6.5% with triple superphosphate. The results also showed that the tuber yield increased by 25.4% when nitrogen used by placement combined with triple superphosphate fertilizer. As a whole, highest tuber yields of all three cultivars, especially in Agria and Banba, were increased under nitrogen placement treatment along with diammonium phosphate.

In order to investigate the effect of application method of phosphate and zinc sulfate fertilizers on some physiological indices of a rhizobium inoculated bean cultivar (Phaseolus vulgaris, cv. Akhtar), a factorial experiment was conducted in a randomized complete block design with three replications in 2016 at Bu-Ali Sina University research farm. The factors were as follows:  Nitrogen starter fertilizer with three levels (0, 30, 60 kgha-1) as the first factor, two methods of zinc sulfate application (broadcasting in soil and foliar application) as second factor, and two phosphate fertilizer application methods (broadcasting and banding placement in soil) as third factor. The maximums of leaf area index (5), total dry weight (1100 gm-2) and crop growth rate (24 gm-2day-1) were observed in the simultaneous application of banding placement phosphate and foliar zinc sulfate in terms of consumption of 30 kg nitrogen per hectare. Compared with the control (no- nitrogen, phosphate and zinc sulfate broadcasted in soil) the maximums of LAI, TDW and CGR were 43, 69 and 92 % higher respectively. In net assimilation rate (NAR) and relative growth rate (CGR), only the main effects of the studied factors were significant. Therefore, phosphate banding placement + foliar zinc sulfate beside 30 kg N ha-1 is the best recommended treatment in rhizobium-inoculated bean to maximize its physiological growth indices.

To study some growth indices of soybean under moisture stress by replacing nitrogen with phosphorus, a field experiment was conducted at the Research Station of Bu-Ali Sina University during the 2017-2018 growing season. The experiment was carried out in a split-factorial arrangement of treatments based on randomized complete block design with three replications. The main plots consisted of three levels of irrigations (irrigating after 60, 90 and 120 mm evaporation from class A evaporation pan). Two levels of nitrogen replacement with phosphorus and without replacement and two levels of phosphorus replacement and without phosphorus replacement assigned to subplots. The results showed that simultaneous replacing of nitrogen and phosphorus in all irrigation levels increased physiological growth indices of leaf area index, dry matter accumulation, crop growth rate, relative growth rate and net assimilation rate. Moisture stress reduced growth rate of the crop significantly. Results also showed that crop growth rate increased 35 to 45 days after planting and reached to its maximum level after 65 days after planting date. After this period, the crop growth rate of soybean decreased and reached to zero about 95-100 days after planting. The highest dry matter accumulation and crop growth rate were obtained from irrigation after 60 mm evaporation and nitrogen-phosphorus simultaneous placement application. According to the results, simultaneous replacing nitrogen and phosphorus, reduced the negative effect of moisture stress on soybean growth indices. Nitrogen replacement with phosphorus increased grain yield by 11.4% as compared to non-replacement of nitrogen with phosphorus and yielded 3855.88 kg.ha-1</sup>. In this research, nitrogen replacement with phosphorus under irrigation after 90 mm evaporation prevented significant oil yield loss as compared to irrigation after 60 mm evaporation.

In order to evaluate seed germination, seedling emergence and changes in growth indices of borage in response to seed priming and water limitation, laboratory tests were laid out as completely randomized design with four replicates and field experiment was carried out as split plot based on randomized complete block design with three replications in 2012. Irrigation treatments (I1, I2, I3 and I4: irrigation after 60, 90, 120 and 150 mm evaporation from class A pan, respectively) and seed priming methods (P0: unprimed, P1: hydro-priming, P2: priming with 100 mM KNO3, P3: priming with 100 mM KH2PO4 for 8 h at 15±1°C) were allocated to main and sub plots, respectively. Results indicated that seed hydro-priming increased germination rate and seedling dry weight of borage by 15.9% and 22.6%, respectively. Emergence rate of borage seedlings was also improved about 7% under different seed treatments. At vegetative stage, leaf area index of plants from seeds primed with water, KNO3 and KH2PO4 was 22.8, 39.7 and 16.1% higher than that of unprimed seeds. At flowering stage, water loss of the plants decreased under water deficit conditions by reducing the leaf area index. All priming techniques, especially hydro-priming, improved leaf area index, particularly under well watering, through increasing seedling emergence rate. Dry matter accumulation, relative growth rate and crop growth rate decreased with increasing irrigation intervals. However, growth duration of plants from primed seeds was longer than those from unprimed seeds, leading to the production of larger plants under well watering.

In order to evaluating effect of smoke-water and urea fertilizer on some growth indices, grain yield and yield components of wheat, a field experiment was conducted as a split plot based on Randomized Complete Block Design with three replications. The experiment was conducted during the season of 2015-2016 at Razi University Research Station, Iran. The experimental treatments were different levels of urea fertilizer application (included 90, 180, 300 and 360 kg ha-1) as main plot and leaf foliar application with different concentrations of smoke-water (included 0, 0.001%, 0.01%, 0.1% and 1% v/v) as sub plot. The results showed that smoke-water significantly improved all evaluated traits and increased wheat grain yield compared to control treatment in all urea fertilizer levels. The highest grain yield (922 g m-2) was obtained in application of 350 kg ha-1 urea and smoke-water at concentration of 1% v/v and the lowest grain yield (339 g m-2) was related to application 90 kg ha-1 urea and foliar with distilled water. The grain yield improved 15.22%, 11.36%, 7.18% and 7.67% by application of 90, 180, 300 and 360 urea kg ha-1 respectively, in smoke-water 1% concentration compared to the control treatment. It seems that smoke-water via improve increasing nitrogen efficiency could increase growth indices and grain yield of wheat.

This study was carried out evaluate the effect of planting dates on the trend of leaf surface growth indicator, growth, and net photosynthesis rates and also the yield of rice cultivars through a split plots experiment based on a randomized complete block design with three replications in the north region of Khuzestan. Main factor was the date of planting at three levels (26 May, 10 Jun, 26 Jun) and the subordinate factor included three cultivars of Red Amber (long and short grains), and Champa. Results of variance analysis indicated that there was a significant difference between different dates of planting and all properties, but no significant difference observed in the interaction of both factors. In addition, the maximum LAI, CGR, and net photosynthesis rate was related to the first date and the highest yield of grain was related to the third date of planting. Evaluating the trend of leaf area indices and crop growthrate on 26 May, which had the maximum thermal stress at the reproductive stage, they reached the maximum growth in a shorter period of time. However, after that, the leaf area indices and the growth rate rapidly reduced, which can be referred to a mechanism of escaping the heat, while the rate of net photosynthesis reached its maximum changes on 26 May. Among the cultivars, short-grain Amber had the minimum changes in above characteristics and Champa had the maximum yield with an average of 3795.4 kg/ha.

This study was conducted to grouping of 10 genotypes of canola via ISSR and IRAP markers and genotype resistance to drought. Eighty five polymorphic bands were produced using 19 individuals and combinations of ISSR and IRAP, and polymorphism varied between 50 to 100. Cluster analysis with UPGMA method placed the 10 genotypes in tree cluster, which includes 5, 3 and 2 respectively. Cluster analysis of germination results based on Euclidean distance with UPGMA method assigned treatment in four different groups consists of 11, 5, 9, and 15 genotypes respectively. Fisher’s linear Discriminant Function Analysis confirmed validity clustering analysis with 95%. The second group had the highest value, for most economical traits. SLM046 genotype could be introduced as resistant genotype by placing different treatments of its in one group. The fourth group included genotypes that had low value for most characteristics. Factor analysis results based on principal components showed that three factors named plumule, radicle and germination percentage, which determined 88.31 percent of total variation. First region was detected as good region on the base first and second factor evaluation. Genotypes in this area were favorable response to drought stress and could be introduced as resistant genotype at germination stage.

This experiment was conducted to evaluate the effects of salt stress on some agro-physiological traits in ten varieties of bread (Triticum aestivum L.) and durum (Triticum turgidum L.) wheats in seedling stage. A greenhouse experiment was carried out as a split plot experiment based on a completely randomized design with four replications in hydroponic condition. Different agronomic and physiological traits (such as Na, K, Ca contents and relative water content (RWC)) were studied. Salinity showed significant effect on all of the studied traits, except for root dry weight and the ratio of Naﰦ. Increase in NaCl level led to significant reductions in all studied traits. The studied genotypes showed significant difference for radicle length, leaf length, seedling dry weight, leaf dry weight, root dry weight, RWC and Na, K, Ca concentrations and Naﲯ and Naﰦ ratios. The genotype × salinity interaction was significant for RWC, Na, Ca and Naﰦ. The salt stress increased the leaf Na while it decreased the K and Ca2 concentrations. The greatest shoot dry weight (0.035 g), root dry weight (0.024 g) and Naﰦ ratio (1.71) were found in genotype Alamot (bread wheat) and the greatest plantlet length (12 cm) was observed in genotype Verinak. The greatest rootlet length (14.63 cm), dry weight of seedlings (0.057 g), RWC (82.20%), membrane stability (0.59), K (3.38 mg/g dry weight) and the smallest Naﲯ ratio (0.17) were detected in genotype Toos (bread wheat). The genotype Toos was identified as the most tolerant genotype to salt stress.

This research was conducted to study the effects of chemical and bio fertilizers on forage yield of alfalfa in a factorial experiment by using a randomized complete block design with 3 replications in 2012-2013 in Arak, Iran. Treatments were chemical fertilizers in four levels (control, potassium, phosphorus and whole micronutrients) and biological fertilizers in four levels (control, soil potassium solublizing bacteria, nitrogen-fixing bacteria and soil phosphorus solublizing bacteria). The results showed that the highest yield of alfalfa, in the first cut, was 1.76 t/ha by the use of phosphorus solublizing bacteria and 1.57 t/ha by using soil potassium solublizing bacteria. Although in the second cut the differences between chemical fertilizer and their interaction with biological fertilizer was not significant, but application of biological fertilizers could affect alfalfa yield in the second cut significantly. Application of soil potassium solublizing bacteria increased forage yield of alfalfa from 1.74 to 2.48 t/ha. The results also revealed that dry forage yield of alfalfa in control treatment was 2.5 t/ha and it was increased to 3.7 t/ha by using phosphorus solubilizing bacteria which is 1.2 t/ha higher than control.

In order to investigate the effect of different planting densities on growth, yield and yield components of two lines of promising soybean cultivation in the summer planting in Gorgan region this experiment was carried out in Gorgan Agricultural Research Station in 2012 (Iraqi area) as factorial arrangement in randomized complete blocks design with three replications. The first factor including plant density at six levels (10, 14, 18, 22, 26 and 30 plants per square meter) and the second factor was two late lines of soya (WE6 and PE10). The results showed that the effect of density on plant height, number of branches, number of pods per plant, harvest index, one thousand-grain weight, grain yield was significant at one percentage probability level. But for other traits became non-significant. Interaction density at line on plant height, harvest index, number of pods, one thousand-seed weight, and grain yield was significant at one percentage probability level. The highest one thousand- grain weight and grain yield was related to the density of 26 plants and the lowest to the density of 10 plants in one square meter. Maximum harvest index, number of pod, one thousand-grain weight was related to line WE6 and the lowest to the PE10. Among the densities, the density of 26 plants per square meter with 2177 kilogram per hectare was allocated the highest grain yield. Generally, with increasing density the amount of yield of two tested lines increased, but line WE6 at density of 26 plants per square meter with 1940 kilogram of seeds per hectare showed superiority.

In study was conducted in two separate experiments in 2011-2013 in seeds and plant improvement institute. In the first experiment، Status growth scion and resistance to spring late frost and content proline in 10 genotypes and cultivar almond، grafted on GF677 rootstock included Touno، Non Pariel، Shokofeh، Sahand، Mamayi، Shahrood 12، A200، 1-25، 1-16 and 13-40 with 10 replication as a completely randomized design and in the second experiment، status their growth in two month period as a completely randomized design، with two factor time and genotypes and with 10 replication was evaluated in seeds and plant improvement institute. Result showed that scions Growth rate of cultivar shokofeh was more than other genotypes and cultivars in each two year. Scion height of cultivar shokofeh in first and second years was 54. 15 and 53. 48 centimeter، respectively. Also، the least height scion belongs to cultivar mamayi and genotypes 1-25 in each two year. Although the leaves start in cultivar shokofeh was later than mamayi and shahrood 12، but rate damage of spring late frost in scions this cultivar was more than other genotypes and cultivar. Genotypes 13-40 showed the most resistance to spring late frost and the most content prolin (29. 75 m mol/ gr fresh weight).

To evaluate the effect of water deficit stress on growth، yield and relationship between growth indices in common bean (Phaseolus vulgaris L.) genotypes، two field studies were performed as split plot arrangement in randomized complete block design with four replications in 2009 and 2010 in Seed and Plant Improvement Institute، Karaj، Iran. Eight genotype (WA4502-1، WA4531-17، D81083، AND1007، Akhtar، COS16، MCD4011، and KS21486) were studied under two irrigation regimes; normal and water deficit conditions. Results showed that water shortage caused significant decrease in LAI in all genotypes. In stress condition، until early pod filling duration (PFD)، AND1007 had higher LAI than other genotypes، however by the end of this stage WA4502-1 was superior. AND1007 genotype had higher CGR than others. Water deficit caused 50% reduction in seed yield. Seed yield loss (%) by drought in AND1007 and D81083 genotypes was the highest and the lowest، respectively. Physiological responses of evaluated genotypes varied in terms of drought tolerance or sensitivity. In this study، drought intensity index (DII) was 0. 50. AND1007، COS16 and MCD4011 genotypes were more tolerant based on DTI، DSI، MP and GMP. Generally، white bean genotypes were more drought sensitive than the red and chitti genotypes.

Crop density is one of the usage tools in sustainable agriculture to carry out integrated weed management. Weed species response varied according to diversity and density of species in agricultural ecosystems. This study was conducted in research field of Ferdowsi University of Mashhad، Iran. Four levels of corn densities (5، 6، 7 and 9 plant m-2) and four levels of species diversity were used including complete control، broad leaved control (corn and narrow leaves)، grass control (corn and broad leaves) and without control (corn، broadleaves and grass weeds) by weeding. All species sampling were done at five stages from 42 days after planting up to the end of growth period. Crop growth rate، total dry matter of weed (TDMw) and total dry matter of corn (TDMc) were measured. Results showed that TDMc was minimum at 9 and 5 plant m-2 in the early growth period، while it was highest at 9 plant m-2 by the end of the growth period. Also، TDMc increased with increasing density in the weed free control، but (TDMc) decreased about 46% in compare with complete control. The same trends were observed for CGR. It was found that broad leaves weeds were more effective than narrow leaves (causing 60 and 34% lower CGR reduction، respectively) on corn growth.

In order to study physiological characteristics of rainfed bread wheat genotypes، an experiment was conducted with 20 genotypes in a randomized complete block design with 4 replications under rainfed and supplementary irrigation conditions. This experiment was carried out at the Dryland Agricultural Research Institute (DARI) in Maragheh during 2007-2008. To determine growth indices، sampling was carried out during growing season. The results revealed that genotype 7 in rainfed and genotypes 1، 7، 12 and 22 in supplementary irrigation conditions had both high CGR and high grain yield. Relative growth rate curve of genotypes 1، 3، 7، 9، 19 and 22 sharply increased than the rest in rainfed condition، so their dry matter accumulation will be faster. This study indicates that high relative growth rate (RGR) cannot be considered the only factor of high grain yield under stress condition، because some high yielding genotypes had low RGR. By contrast، genotypes with high RGR produced high grain yield in supplementary condition.

In order to investigate the effects of different irrigation regimes and zeolit on the yield، yield components and relative leaf water content of sorghum، a field experiment was conducted in split plot in time and space based on randomized complete block design with three replicates in research station of Shahid Bahonar University of Kerman in 2011. Irrigation regimes (100، 80، 60 and 40% of field capacity) and different amounts of zeolite (control، 150 and 300 kg ha-1) were arranged as main and sub plots، respectively. Irrigation regimes showed significant effect on all traits (fresh weight، dry mater، height، relative water content etc.) except stem node number. Meantime، all the traits except stem height، relative water content and the crop growth rate at the first and fourth stage of sampling affected by super absorbent so that the highest amount of the measured traits were recorded for 300 kg ha-1 super absorbent. Interaction effect of the irrigation water × SAP × harvest was significant for fresh weight. The highest FW in second harvest belonged to I100 × 300 kg ha-1 SAP. At the end، it can be concluded that application of 300 kg ha-1 super absorbent in irrigation levels lower than field capacity will result in 20% increase in yield.

The allelopathic effect of weeds is one of the important limiting factors that affects the growth and yield of medicinal plants. The allelophatic effects of water extract of purple nutsedge (Cyperas rotundus), creeping jenny (Convonvolus arvensis), bermuda grass (Cynodon dactylon), redroot pigweed (Amaranthus retroflexus), common cocklebur (Xantium strumarium L.), perennial night shade (Solanum nigrum), and sunflower (Helianthus annus) on germination and initial growth of indigo plant (Indigofera tinctoria L.) were investigated. The results showed that, application of extract of all plants decreased percentage rate and uniformity of germination of indigo seeds, also increased the time up to 5, 10, 50, 90 and 95 percent of germination. The lowest percentage of germination (Gmax) was found in bermuda grass and redroot pigweed seeds. The highest seed germination rate was belonging to common cocklebur. The extract of perennial night shade was maximum uniformity effects on germination (GU) of indigo seeds. The highest reduction of radicle and plumule growth was found by use of perennial night shade, creeping jenny, bermuda grass and sunflower extracts. Perennial night shade had the highest effects of reduction of shoot dry weight. Among the all plant extracts, the lowest allelopathic effect on germination, and seedling growth was belonging to common cocklebur.