فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 40 (زمستان 1395)

To study the effect of different organic and chemical fertilizers on weed biomass and some characteristics of safflower, a factorial experiment based on randomized complete block design with three replications was done at the Urmia University Reaearch Farm in 2013. Treatments consisted of growing of cover crops (red clover, grass pea, hairy, bitter vetch) along with the safflower rows and two weed control treatments (with and without weed) as a first factor and application of organic manure (cattle manure渪ὺ뭢阬) and the different nitrogen and phosphuros fertilizer levels (100 % of recommended chemical fertilizer, 67 and 63 % of recommended N and P, 50 and 40 % of recommended N and P) as second factor. Results showed that the biomass yield of broad and narrow leaf weeds affected by the combined treatments of cover crops and use of fertilizers. The biomass yield of broad and narrow leaf weeds were redused by 74.78, 82.22% under vetch cover crop when 50 and 40% of recommended N and P fertilizers were used, in comparison with sole culture of safflower and use of 100% of recommended chemical fertilizers. The maximum of seed yield (3431 kg.ha-1) and biological yield (8239 kg.ha-1) of safflower obtained from using 100% of recommended chemical fertilizers and without growing cover crops. Results, as a whole, showed that at higher levels of chemical fertilizers the competitive effects of weeds on safflower were higher than lower levels of fertilizers.

Due to the dependency of direct seeding of rice on the application of herbicide and possibility of weed resistance to herbicides, the use of mixtures of herbicides is of considerable importance. To evaluate the effectiveness of consecutive applications of some herbicides with lower concentrations, including Thiobencarb, Pretilachlor, Bensulfuronmethyl, Ethoxysulfuron Anilofos, Butachlor, and Propanil, on weed density, yield and yield components of rice (Oryza sativa L. cv. Hashemi) an experiment based on a randomized complete block design with eight treatments and three replications was conducted at the Research Farm of Faculty of Agricultural Sciences, University of Guilan in 2014. The results showed that plant height, seed yield, dry matter yield, harvest index, number of tillers and number fertile florets per panicle were affected by these treatments. Tandem use of Thiobencarb (9 day before sowing), Bensulfuronmethyl (9 day after sowing) and Propanil (30 day after sowing) affected weed dry matter and weed density by 92 and 98 %, respectively. The highest number of fertile floret per panicle (71 pcs) and tillers number per plant (14 pcs) were observed in plots where Thiobencarb, Bensulfuronmethyl and Propanil were used consecutively. In this treatment, seed yield and biological yield increased by 72 and 73 percent respectively as compared with that of control. Application of Pretilachlor caused phytotoxicity, where by reduced plant height and seed yield. The highest grain yield of rice (3092 kg.ha-1) was produced by consecutive use of Thiobencarb, Bensulfuronmethyl and Propanil. This treatment was more effective in reducing density of weeds and their dry matters than of two times hand weeding. The use of Thiobencarb followed by Bensulfuronmethyl and Propanil was the most effective treatment in this expriement.

An experiment was conducted to study possible reduction of concentration (dose) of phenmedipham desmedipham ethofumesate herbicides at different application times to control weeds in sugar beet field. Thus, a factorial experiment based on complete randomized block design with three replications was performed at Sabzevar, Khorasan-e-Razavi in 2013. Factors consisted of herbicide dosages (control, 75% of the recommended dosage, and 125% of recommended dosage and application times at 2-4, 4-8 and 8-12 leaf stages of sugar beet. Herbicide used in the experiment was phenmedipham (9.2%) desmedipham (7.2%) ethofumesate (11.3%) (PROGRESS OF BETAMIX) as 877 ga.i ha-1 27.4 EC. The results indicated that the delayed application of herbicide increased weed density by 55.92% and weed dry matter by 33%. Application of herbicide at 4-8 leaf stage produced highest root and sugar yields. Root impurities were not affected by the time of herbicide application. Used of 125% of recommended dosage resulted in lowest weed density and weed dry matter and highest root and sugar yields. Impure sugar percentage and K content was not affected by herbicide dosage. Other root quality characteristics were not statistically significant different between the recommended dose 125% of recommended dosages. Results as a wholes suggested that at early growth stage of sugar beet (2-4 leaf stage) lower herbicide dosage and at later growth stage of sugar beet (8-12 leaf stage) higher herbicide dosage may produce highest root yield of sugar beet.

To evaluate the effects of application of herbicides and different plant densities on seed yield, weed density and chlorophyll content in wheat (cv. Bahar), a split plot experiment based on randomized complete blocks design with three replications was conducted at the Agricultural Research Staion of Sarableh, Ilam, in 2014-2015 cropping season. Plant densities in (200, 250 and 300 kg of seed/ha) were considered as main factor and application of herbicides (2, 4-D, Granstar, Shovalyeh, and control, without herbicide application) as sub factor. Results indicated that plant densities affected traits under study significantly. As a result number of seed per spike, 1000-seed weight, relative water content, chlorophyll a and b contents decreased, while weed density and weed dry weight number of spike per m2 and percent lodging increased by increasing plant density. Application of herbicide increased number of spike per m2, number of seed per spike, 1000 seed weight, harvest index, relative water content, chlorophyll a and b contents, while it decreased weed dry weight and its density. Interaction effect of plant density and application of herbicide were significant on seed yield and biological yield. The highest seed yield (5500 kg.ha-1) was produced by using 250 kg seed/ha and application of Granstar herbicide and the lowest (2400 kg.ha-1) from 200 kg seed/ha and without application of herbicide. Thus, using 250 kg seed/ha and Granstar herbicide would increase wheat seed yield in this region as compared with the other treatments.

To investigate the effect of foliar application of plants with growth stimulants and seed priming on yield and seed oil content of flax, a factorial experiment was conducted at the Saatlo Agricultural and Natural Resources Research Center of West Azarbaijan based on a randomized complete block design with three replication in 2015. The first factor was two varieties of flax seed (yellow, white flowered and brown, purple flowered), the second factor was seed priming consisted of 3 levels (control, hydro-priming and priming with Auxin GA) and the third factor was foliar application of growth stimulants with three levels (control, Auxin and GA). The results showed that effect of seed priming was significant on all traits except pod weight, thousand seed weight and seed oil percent. Foliar application of plants with growth stimulants were also, significant on plant height, seed number/plant, pod weight, biological yield, seed yield and grain oil percent. Interaction of cultivar and priming on seed weight and seed yield and also on cultivar with foliar application were significant on plant height and pod weight and seed oil percent. Interaction of priming and foliar application on plant height, number of branches, number of pods/plant, pod weight, seed yield and seed oil percent was also observed. Brown purple flowering flax cultivar had higher seed yield and seed oil percent as compared with yellow white flowering flax seed. Seed priming and foliar application of plants with growth stimulants, and seed priming with Auxin GA along with foliar application of GA produced highest seed yield and seed oil percent, as compared with other treatments.

Brago is an important medicinal plant. This study, thus, was conducted with different levels of nano particles of titanium (0.01, 0.03 and 0.05%) and elemental titanium on its different growth stages (4-5 leaf, flowering and after flowering) with four replications in a factorial experiment based on randomized complete block design at the Agricultural Field of Rement Village of Babol, Mazandaran, Iran, in 2012. Results showed that there were a significant differences between treatments of titanium, time of treatments and between their interactions. Among the traits under study, leaf fresh weight, leaf dry weight, stem fresh weigh at 1% and plant hight, stem dry weight, total plant fresh weight and total plant dry weight at %5 levels of probabilities showed significant differences for their interaction between different treatments of titanium and different stage of development. The highest plant height, leaf dry weight and plant fresh weight and plant dry weight were produced when nano particles of titanium applied after flowering stage. Where as, the highest fresh leaf, fresh stem weight and total plant fresh weights were obtained when plants treated with titanium at flowering stage. On the other hand, dry weight of flowering branches showed significant negative correlation with GPX antioxidant enzyme. The lowest GPX antioxidant enzyme was produced when nano particles of titanium were applied after flowering stage at 0.01% probability level. As a whole, the results of this experiment suggest that there are significant differences among titanium treatments when they are applied at different growth stages of this plant. This study also showed that application of nano particles of titanium after flowering of this plant increased its flowering branches.

Marigold is an ornamental and medicinal plant and has also industrial in cosmetalogical uses. To evaluate the effects of vermicompost and seaweed fertilizers on some morpho-physiological properties of the plant, a factorial experiment based on a randomized complete block (RCB) design with three replications was conducted in pot in Mianeh. In this experiment, the first factor was vermicompost fertilizer at four levels (0, 5, 10 and 15 t.ha-1) added to the pot soil and the second factor was for levels of liquid seaweed fertilizer (0, 1, 2 and 3 percent) sprayed on foliage. The assessed traits were leaf, root and stem dry weights, root volume, number of secondary shoots, plant height, leaf number, flowering period, number of flowers, flower diameter, dry weight of flowers, leaves electrolyte leakage, leaf area (LA) and essential oil percentage and yield. The results showed that application of vermicompost increased some traits, including plant height (18.58 cm), number of branches (4.3 branches), root volume (3.4 cm³) and leaf area index (65.55 cm2). Using 3 percent of liquid seaweed fertilizer was also effective. In general, application of 5 tons per hectare of vermicompost with 3 percent of liquid seaweed fertilizer resulted in highest flower and stem dry weights.

To identify drought tolerant lines among 168 recombinant inbred lines derived from a cross between Hindi variety of L3685 (high yielding, erect type and early growth) as female parent and Iranian variety of Qazvin (with prostrate growth and late growth) as male parent, two experiments were conducted in randomized complete block design with three replications under non-stress and drought stress conditions at the experimental Field of Shahrekord University in 2013. Results of combined analysis of variance showed that there were significant differences among lines under study in both experimental conditions in terms of grain yield (P≤0.01). Significant interaction of line×conditions revealed that lines responded differently to drought stress based on grain yield. Results also indicates that lines 160, 125 and 129 were promising lines under both conditions in terms of grain yield. Positive and significant correlation between tolerance indices and grain yield under stress and non-stress conditions indicated that the STI, MP, HARM and GMP indices may identify promising from non promising lines. Based on the above criteria, lines 160, 125, 48, 103 and 129 were recognized as drought tolerant lines. According to the results of principal components analysis, the first and second components determined 97.8% of the total variations among genotypes under study for drought resistance indices. The distribution of lines in the biplot showed genetic variations to the drought stress and thus lines 160, 125, 48, 129 and 103 were identified as high yielders under drought stress condition.

To study the relationships of grain yield and some of agro-morphological traits in 40 doubled haploid (DH) lines along with parental and three check genotypes in a randomized complete block design with two replications under two water regimes (normal and stress) were evaluated during 2011-2012 and 2012-2013 growing seasons. Combined analysis of variance showed significant difference for all the traits in terms of the year, water regimes, lines, and and line × year. Comparison of group means, between non-stress and stress conditions, showed that DH lines had the lowest reduction percentage for the number of grains per spike, thousand grain weight, grain yield and biological yield as opposed to check genotypes. The correlation between grain yield with biological yield, harvest index, thousand grain weight, and hectoliter of kernel weight in both conditions, were highly significant and positive. Based on stepwise regression the peduncle length, number of seeds per spike, thousand seed weight, and hectoliter of kernel weight had important effect on increasing seed yield. The result of path analysis showed that these traits had the highest direct effect on grain yield. Based on mean comparisons of morphological characters as well as STI and GMP indices it can be concluded that lines No.11, 13, 14, 24, 29, 30, 35 and 39 were distinguished to be desirable lines for grain yield and their related traits and also tolerant lines in terms of response to drought stress conditions.

Drought stress is one of the main limiting factors crop production in arid and semiarid regions. In this study, drought tolerance of 19 wheat genotypes were evaluated by using UPGMA cluster analysis. To this end, the effect of drought stress on a number of related agronomic and physiological traits of wheat genotypes, belonging to three groups of sensitive, intermediate and drought tolerant, under three conditions of normal, moderate and severe drought stress were studied. A factorial experiment based on completely randomized design with three replications was performed. Traits like plant height, shoot fresh weight, spike length, awn length, shoot dry weight, seed yield and relative water content of genotypes were measured. Analysis of variance showed that the effects of drought on all traits except awn length were significant. Most of the traits were negatively affected by drought stress. Highest reduction was observed in grain yield. Cluster analysis grouped genotypes exposed to drought stresses in to three categories. Genotypes numbering 15, 13, 12, 16 and 17 expirienced low means in all of traits under study. The results also showed that the second and third groups, resulting from cluster analysis, were in agreement with the results of previous researches reported. The first cluster, however, was found to be inconsistent with their initial introduction grouping under severe drought stress conditions. Therefore, the initial grouping was consistent especially in most of sensitive and tolerant genotypes under severe drought stress conditions.

To study the effects of using different levels manure under salt stress conditions on the quantity and quality of rosemary a field experiment is conducted in split plot experiment based on randomized complete block design with three replications at Zahedan during fall season of 2013-2014. The experimental treatments consisted of salinity with two levels (irrigating the field with drinking water of Zahedan [EC = 1.1 ds/m (S1)] and irrigating the field with salty water of Zahedan [EC = 4.4 ds/m (S2)] considered as the main factor and using manure with four levels (M1- without manure, M2- 15 t.ha-1, M3 - 30 t.ha-1 and M4 - 45 t.ha-1) as sub factor. Traits evaluated were plant height, leaf dry weight, leaf to stem ratio, shoot dry weight, percentage and yield of essence. Experimental results showed the salt stress did not affect significantly plant height, shoot fresh weight, shoot dry weight, biomass and essence of rosemary as comparied with drinking water (non-salinity), but a decreasing effect of saline water was observed. Using 45 t.ha-1 of manure, in comparison with other manure treatments, did have beneficial effect on most of the traits under study. However, no significant difference was observed between this treatment and with that of 30 t/ha. The simple correlation showed there is a positive and significant relationship between plant biomass and all other traits. The results also showed that there was positive and significant relationship between essence percentage and essence yield.

This experiment was carried out to determine the effects of heat stress, due to different planting dates, on the peduncle anatomy of rice cultivars and their grain yields. It was performed in a split-plot experiment using randomized complete blocks design with three replications in 2006 and 2007 cropping seasons at the Shavoor Agricultural and Natural Resources Research Center of Khuzestan. Three planting dates (May 5th. with 20 days intervals), to expose rice cultivars to different tempratures, were assigned to main plots and cultivars (Hoveizeh, Hamar, heat tolerant, Ghermez Anbori, Champa, heat sensitive, and Danial, relatively heat tolerant) to sub-plots. The results of combined analysis showed that the effects of planting date× variety interactions were significant for all of traits, including air channel surface, large vascular bundles surface, xylem and phloem. This indicates that cultivars reacted differently to planting dates. Lowest and highest airchannels surface levels were related to 1st and 2nd planting dates (15492.23 and 21144.38 µm2) and to Hoveizeh and Champa cultivars (15492.23 and 23411.18 µm2) respectively. Lowest and highest xylem surface obtained in 3rd and 1st planting dates (741.37 and 898.03 µm2) respectively. But, lowest and highest level of large vascular bundles were optained in 2nd and 3rd planting dates (15514.20 and 15983.93 µm2)and for phloem (3121.68 and 3437.55 µm2)respectively. Based on these results it can be said that the reduction of large vascular bundles surface and phloem in 1st and 2nd planting date are mechanisms of water conservation and maintaining cell turgor pressure. Increasing xylem vascular bundle surface also, would facilitate availability of water to plant under drought stress conditions.

Timely transplanting is one of the major objectives of success in double cropping of rice. To determine the best transplanting dates for double cropping of Tarom mahalli in Mazandaran, a field experiment was carried out in a Randomized Complete Block Design with three replicaties in Amol in 2014. Treatments were: 24 transplanting dates beginning from June 28 to September 5 with intervals of three days. The results of analysis of variance indicated that there were significant differences among different transplanting dates for all agronomic traits and grain yield at 1% probability levels. Delaying transplanting increased unfilled grain number per panicle and decreased other agronomic traits including seed yield. The highest grain yield (with an average of 3975.2 kg.ha-1) was obtained at 1st of July transplanting date. This was due to the increase in the number of seeds (80.3), number of filled seed per panicle (72) and panicle number per plant (18.3). The lowest grain yield (with an average of 38.5 kg.ha-1) was obtained at the 5th of September transplanting. Early transplanting decreased days to different phonological stages (days to tillering, 50% flowering and maturity). Delay in transplanting, however, reduced daily temperature, increased number of days to the developmental stages and thus decreased seed yield. Early July transplanting due to suitable temperatures and radiation for flowering and lack of heavy rainfall increased seed yield of rice. It could be concluded that transplanting from the 28th of June to the 10th of July can be considered as the optimum transplanting date for double cropping of rice (var. Tarom mahalli) at Amol climatic conditions.

To investigate relationships among physiological traits of 20 rapeseed cultivars, an experiment was conducted at the Research Farm of Agricultural Faculty of Shirvan in Northern Khorasan in Iran, in 2014-2015. The experiment used was a randomized complete block design with four replications. Results showed that there were significant differences among cultivars for seed and biological yield, the number of pod/plant and seed/pod, 1000 seed weight, harvest index, days to germination, seedling, rosette, shooting, flowering time, end of flowering, pod formation time, end of pod formation, seed filling time and physiological maturity among the traits of rapeseed under study. The highest yield belonged to Traviata (513.56 g/m2) but did not have significant difference with Kodiak, Bilbao, L72 and SW102. The lowest yield belonged to Shirali cultivar (344.41 g.m-2) but it also did not have significant difference with Zarfam and Sarigol cultivars. Positive and significant correlation was observed for seed and biological yields, number of pods/plant and seeds/pod, seed weight, harvest index, the number of days to flowering, flowering end, beginning pod formation, ending pod formation, beginning seed filling, plant height and seed filling rate, but correlations were negative between seed yield and seed filling period and day to emergence and rosette. According to stepwise regression, seed yield was considered as dependent variable and other traits as independent ones. Positive direct effects of harvest index and biological yield and also positive indirect effect of biological yield on number of pod/plant and positive indirect effect number of pod/plant on harvest index were the traits that can be used for selection of high yielding genotypes. Path analysis revealed that traits like seed weight and seed number per unit, seed number and seed weight are its determiners of seed yield. The results also showed that seed filling rate is more effect than seed filling period in determination of seed weight. Regression analysis also showed that by increasing temperature, seed filling period was decreased by 1.54 days and seed filling rate increased 0.004 mg/grain.day-1 centigrad-1. Based on these results it could be concluded that genotypes varied significantly for the rate and duration of seed filling.

Maize has an important role in livestock nutrition. Thus, improving its forage quality through agronomical managements seems to be of high importance. To evaluate quality traits of forage maize cultivars in response to plant densities, a factorial experiment based on RCBD with three replications was carried out at the Research Station of Faculty of Agriculture, University of Maragheh during 2013-2014 growing season. The first factor was plant density with three levels (93000, 105000 and 119000 plant.ha-1) and the second factor was maize cultivars with five levels (Zola, Simon, NS, 540 and 370). Results of the experiment indicated that dry matter production was affected by the interaction of plant density and cultivar, where cultivar 540 produced the highest dry forage (980 g.m-2) by density of 119000 plant.h-1 and cultivar NS the lowest (933 g.m-2) dry forage by density of 93000 plant.m-2. However, all cultivars under study produced higher dry matter under higher plant densities. It was also observed that Zola cultivar, with 638 g.kg-1 of hemicellulose, had the lowest forage quality. Other cultivars were in the same statistical group. Phosphorous content of forage was in its highest value in 93000 plant density, while calcium content was not affected by plant density. Lower plant densities resulted in higher crude protein content. Cultivar no. 540 produced the highest crude protein yield (kg.ha-1) suggesting its superiority to the other cultivar. This cultivar can be recommended for growing in this region and other regions with same climatic conditions for producing high quality and quantity of maize forage production.

To investigate the effects of different fertilizer applications and sesame/cowpea intercropping systems on soil fertility, a split plot experiment based on randomized complete block design was conducted in Fasa, Fars province, during 2014. The main plots were five fertilizer levels consisted of: using chemical fertilizers nitrogenꘚⲦᨫꋫ (F1), organic fertilizers (F2), biofertilizers (F3), 50% chemical fertilizer 50% organic fertilizer (F4) and 50% chemical fertilizer 50% biofertilizer (F5), and sub plots consisted of: sole cropping of sesame (M1), sole cropping of cowpea (M2), 50:50 sesame-cowpea intercropping (M3), 75:25 sesame-cowpea intercropping (M4) and 25:75 sesame-cowpea intercropping (M5). The results showed that soil fertility and cropping systems affected the yield and yield components of sesame and cowpea significantly. The highest yield of sesame (1292.6 kg.ha-1), and cowpea (3772.4 kg.ha-1) were obtained from their sole croppings. Among the applications of fertilizer, the highest yield of sesame (950.49 kg.ha-1) and cowpea (2582.50 kg.ha-1) belonged to bioorganic and biofertilizer treatments, respectively. In spite of these results, the highest land equivalent ratio (LER) belonged to F4 (1.24) and M3 (1.03) treatments. In general, according to the results, it seems that 50:50 sesame-cowpea intercropping (M3) and application of 30 kg.ha-1 N 50 kg.ha-1 P 150 kg.ha-1 bio-organic fertilizer (F4), may reduce application of chemical fertilizers and be beneficial to sesame-cowpea intercropping system.

Seeds could be deteriorated during storage. Treatment of seeds by humic acid induces metabolic and biochemical changes which accelerate seed germination and its emergence. This research was carried out to evaluate the effect of seed pretreatment potassium humate on its deterioration under laboratory and greenhouse conditions. The experiment was carried out in a 5 × 4 × 3 factorial experiment using completely randomized design with three replications. Experimental factors were three levels of potassium humate (control, one and two parts per 1000 potassium humate), four wheat varieties (Shirodi, Darya, Morvarid and Chamran) and five heating times (zero, 48, 72, 96 and 144 hours). Results showed significant differences in simple effect of variety and effect of potassium humate × heating times for shoot length; simple effect of heating times and effect of potassium humate × varieties for germination percent; effect of potassium humate × varieties × heating times for radicle length, shoot dry weight, seminal roots dry weight and seedling dry weight. Pretreatment of seeds by using 2/1000 potassium humate produced × longest radicle roots in Shirodi, Darya, Morvarid and Chamran respectively with 72, 72, 144 and 96 hours heating times. The highest root dry weight was produced by 2/1000 potassium humate and 48 and 72 hours of heating times on Shirodi and Chamran, respectively. Application of 1/1000 of potassium humate produced the highest seedling dry weight in Shirodi, Darya and Morvarid with 48, 72 hours of heating times and without heating, respectively. Results also revealed that different varieties responded differently to potassium humate treatment at different heating times. It can be concluded that longer heating durations affected wheat characters at early growth stages and pretreatment of seeds by potassium humate can decrease seed deterioration.