نشریه بوم شناسی گیاهان زراعی
سال نهم شماره 4 (پیاپی 33، زمستان 1392)

This study was conducted to determine grain yield stability of rainfed promising barley genotypes in six Iranian rainfed research stations (Maragheh، Sararood، Uromieh، Ghamloo، Zanjan and Ardabil) under cold and semi-cold conditions during three cropping seasons (2006-2009). The studied genotypes were 10 promising barley lines along with two checks (one local variety and newly released variety of Abidar). In each environment، the experiment was arranged in randomized complete block design (RCBD) with four replications. Results of combined ANOVA showed that location، year، genotype، interaction oflocation and genotype، and interaction of year، location and genotype had significant effect on grain yield. The genotypes showed the highest and the lowest grain yield in Sararood (2549 Kg/ha) and Zanjan (1578 Kg/ha) stations، respectively. Line No. 9 produced the highest grain yield (2061 Kg/ha). To study the interaction of genotype and environment، GGE biplot method was used. Based on the polygonal graphs related to genotypes، genotype No. 1 (G1) produced the highest yield in Ardabil and genotype No. 5 (G5) showed the highest yield in Zanjan، Maragheh and Uromieh. Besides، genotype 3 (G3) and genotype 4 (G4) produced the highest yield in Ghamloo and Sararood stations، respectively. Based on the theoretical ideal environments graph، Uromieh was closer to the ideal environment. Regarding to the imaginary ideal genotype graph and biplot of genotypes and environments، genotype No. 5 was identified as the best one due to its higher yield and better yield stability.

In order to study the effect of agricultural management on nitrogen nutrition index of canola، a field experimental was conducted in 2010. Experiment was carried out as a nested completely randomized design with three replications. In this field experiment، 15 canola fields were comparatively studied in three levels of management (optimum، middle، weak) in Gorgan area، Iran. Sampling was performed at four stages and characteristics including plant density and height، leaf area index، dry weight، total nitrogen percent، biological yield and harvest index were measured. Also، nitrogen nutrition index was determined at stem formation، flowering and carpetbag stages. The results showed that all the studied management levels and farms within each level were significantly different from nitrogen nutrition index point of view. Positive significant correlation between nitrogen nutrition index with seed and biological yeild at yellow bud stage revealed the importance of nitrogen sources access at flowering and seedbag filling stages. Although nitrogen nutrition index was higher in optimum level of management than in the middle and weak ones، but during growing season and in all management levels، the index was less than 1 that indicates nitrogen deficiency. Thus، it could be concluded that nitrogen is a limitation factor in canola production in Gorgan area، Iran.

The effect of water use optimizing on yield، yield components، harvest index and biomass of two wheat cultivars (Zarrin and Gaspard) in intercropping and sole cropping systems was evaluated in research farm of agriculture faculty of Zanjan university، Iran during 2010-2011. Experiment was carried out as split block based on a randomized complete block design with three replications. Factors were planting pattern at three levels of 100% Zarrin، 50% Zarrin+50% Gaspard، and 100% Gaspard and irrigation at four levels of full irrigation in all growth stages (control)، irrigation interrupt at shooting stage of wheat، irrigation interrupt at grain milky stage، and irrigation interrupt at grain hardening crummy stage. Results showed that irrigation had a significant effect on grain yield، biomass، harvest index، the average number of grains per spike and 1000 grain weight. The interaction effect of the factors and planting pattern levels on grain yield، biomass، harvest index، the average number of grains per spike was also significant. The highest grain yield (7905 kg. ha-1) was obtained from control in intercropping of Gaspard and Zarrin that was 2. 14 and 24. 98 percent higher than that of Gaspard and Zarrin sole cropping، respectively. Land equivalent ratio index (LER) was more than one at treatments of irrigation interrupt at grain hardening (1. 26) and control (1. 1) in intercropping and showed that Gaspard and Zarrin intercropping was better than sole cropping system. Results also revealed the possiblity of reducing once irrigation in grain hardening crummy stage for Zarrin and Gaspard varieties production.

Soil waterlogging and puddling operations affect many soil parameters which may cause major changes in many soil properties. In order to evaluate the effect of irrigated rice cultivation on some physical and chemical properties of soils in Gonbad-e- Kavus، Iran، six profiles were dugged in rice cultivation areas، dryland cultivation، and pasture. These areas had identical conditions in terms of parent material، climate، and topography. After dissecting the profiles، a number of important parameters affecting soil quality including texture، structure، organic carbon percentage، percentage of neutralized solutes، saturated mud acidity، cation exchange capacity، and electrical conductivity were studied. Results showed that rice cultivation using puddling operation and waterlogging method changed many soil properties. Soil processes were intensified in the surface layer of lands under rice cultivation due to moisture and suitable temperature. It caused an increment in clay and CEC، and lime percentage was increased in deep parts of the soil، which led calcic horizons formation. Microbial activity in irrigated rice cultivation areas decreased pH in surface layer of the soil by increasing organic matter and carbon dioxide. The electrical conductivity of the surface layer of soils under rice cultivation was also more than that in dry cultivation and pasture، due to more water evaporation and salts remains. Therefore، rice cultivation decreases the performance of the plants which are in rotation with rice by creating limitation for them.

The effect of paclobutrazol and irrigation duration on concentration of some nutritional macro elements in citrange and citromelo rootstocks leaves was evaluated. Experiment was carried out as factorial based on a randomized complete block design in Tonekabon، Iran. Factors included paclobutrazol at three levels (0، 0. 25 and 0. 75 g) and irrigation duration in three levels (3، 6 and 9 days) and rootstocks in two levels (citrange and citromelo). The results showed that paclobutrazol، rootstock and irrigation duration affected concentration of nutritional elements، significantly. Concentration of phosphor، nitrogen، potassium، calcium and magnesium in citromelo rootstock was significantly more than that in citrange rootstock. Also، results showed that increasing irrigation duration from 3 to 9 days، decreased concentration of nitrogen and calcium in both citrange and citromelo rootstocks. Concentration of phosphorus was decreased with increasing irrigation duration in citrange rootstock، but it was increased in citromelo. In conclusion، pacloboutrazol significantly increased nutritional elements in both rootstocks and concentration of 0. 25 g. l-1 pacloboutrazol was better than 0. 75 g. l-1 in nutritional element absorbtion.

In order to study the effects of different fertilizer treatments in systems of rice Intensification (SRI) on rice water productivity، an experiment was performed at Rice Research Institute of Iran (Rasht) during cropping season of 2011. Treatments consisted of traditional farming methods with conventional fertilizer application، improved cultural methods and eight different combination of organic and chemical fertilizers use in SRI. The results showed that yield، total biomass، harvest index، number of tillers per square meter and water productivity in SRI was statistically higher than them in conventional farming methods. Urban waste compost plus 50% of conventional chemical fertilizer resulted in the highest grain yield (3122 kg/ha) and water productivity (1. 56 m2/ha) and so it was identified as the best fertilizer treatment in SRI with 50% reduction in chemical fertilizer application.

Tobacco topping and sucker control provides an opportunity for plant to use its maximum potential for leaf development and higher quality and yield production. This study was conducted to determine the best suckercides and optimal amount of them for suckers control. This experiment was performed as a randomized complete block design with seven treatments and four replications in Tirtash Research and Education Center، Mazandaran، Iran. Treatments were prim plus levels (12. 5، 15 and 17. 5 ml per plant)، fatty alcohol 15 ml per plant، fatty alcohol 15 ml with prime plus 17. 5 ml per plant، topping and a control (no suckercide، no topped and no suckercide). Cured leaf yield، number of suckers، dry and green weight of suckers per plant، price of one kilogram tobacco and income per hectare، sugar and nicotine percent، burning time and fill capacity were recorded for all treatments. Results of analysis of variance showed significant differences of treatments for the studied traits except for qualitative characteristics. Fatty alcohol 15 ml with prime plus 17. 5 ml per plant، prime plus 15 and prime plus 17. 5 ml per plant were better treatments with 2925، 2890 and 2745 kg/ha cured leaf yield and 10654، 10418 and 10214 rails price for one kilogram tobacco، respectively.

Seed nutrient priming is a simple and low cost method for nutrition، germination and primary growth improvement of crops. In order to evaluate the effect of seed priming on germination and flower yield of marigold (Calendula officinalis L.)، an experiment was conducted in Islamic Azad University، Tabriz Branch in 2011. Treatments were seed priming with zinc and manganese at concentrations of 0. 5، 1%، 1. 5% and 2%، Zn- 1%+Mn1%، Zn1. 5%+Mn1% and a control. Mean final germination percentage of seeds treated with zinc and manganese alone was 79% and 79. 5%، respectively، while in control only 71% of seeds completed the germination process. Increasing of zinc and manganese concentrations resulted in lower seedling vigor index. Flower yield in treatments of ZnSO41%+MnSO41%، MnSO41. 5%، ZnSO41. 5%+MnS 41%، ZnSO41. 5% and ZnSO42% produced higher flower yield، respectively. Two combined treatments were significantly different in essential oil yield، and essence yield in Zn1. 5%+Mn1% was 0. 03 ml. ha-1 lower than Z 1%+Mn1%. Response of essential oil yield to the studied treatments was positive and significant and all treatments produced higher yield in comparison to the control، exept 0. 5%Zn and 0. 5% Mn. In conclusion، seed priming with zinc and manganese solutions could be recommended as a method for improving marigold essential oil yield in field condition.