نشریه بوم شناسی گیاهان زراعی
سال هشتم شماره 4 (پیاپی 29، زمستان 1391)

Yield and yield components response of chickpea to time and different levels of humic acid foliar application was studied in Bardaskan (northeast Iran) in 2011. experiment was carried out as factorial based on a complete randomized block design with three replications. Factors were foliar application time of humic acid at three levels (three leaf, flowering and poding stages), and different levels of humic acid concentrations (0, 2, 4 and 6 Lit.ha-1). Humic acid 8% was used with Humax trade name containing 80% humic acid, 5% potassium oxide and 15% fulvic acid. Yield and yield components response were different to foliar application time. Foliar application at flowering stage had the greatest effect on pod number per plant, seed number per plant, economic yield and biological yield, while foliar application at three leaf stage had the highest effect on plant height and lateral branches number in plant. Increasing humic acid level increased all parameters, except lateral branches number in plant. The highest pod number per plant, seed number per plant, economic yield and biological yield was obtained at 6 lit.ha-1 humic acid concentration. Overall, the result of this experiment showed that 6 lit.ha-1 humic acid application at poding stage can be recommended to achieve optimal economic performance.

A filed experiment was conducted to determine the effects of urea starter fertilizer and post emergence herbicide effects on weed interference in early season cotton production and some agronomic traits of cotton plants in Gorgan region (northeast Iran) in 2008. Experiment was carried out as factorial based on a randomized complete block design with four replications. First factor was weed management at four levels including early post emergence application of Methazole + Envoc in early cotton growth, late post emergence application of Methazole + Envoc in 15-20 cm cotton plant height period, early hand weeding and late hand weeding in cotton growth season, and four levels of starter fertilizer as the second factor were 0, 50, 100 and 150 percent of recommended dosage of urea starter fertilizer (175 kg.ha-1), respectively. Planted cotton cultivar was Siokra, one of commercial verities in Golestan province. Late hand weeding and late herbicide application resulted in the highest amounts of whole weed biomass 10 day after weed control (W1) and a month after weed control (W2). Increasing urea starter fertilizer level increased weed biomass 10 day after weed control, but decreased it a month after weed control.

In order to evaluate the effect of growth habit on agronomic traits such as days to heading and physiological maturity, grain filling period, plant height, 1000 kernel weight and grain yield, an experiment was conducted as randomize complete block design with three replications with 259 barley genotypes at Maragheh dryland agricultural research station during 2004–2006. Based on the growth habit, genotypes were grouped as winter type (62.16%), facultative type (15.44%) and spring type (22.4%). Comparison of means for grain yield showed that there were high significant differences between winter with facultative and winter with spring types, but it was not significant between facultative and spring types. Spring-type genotypes had the highest grain yield mean with 2893 Kg ha-1. The existence of negative correlation between growth habit and grain yield and 1000 kernel weight showed that spring type genotypes had high yield and 1000 kernel weight. There were also negative correlation between growth habit and days to heading, maturity and plant height indicating that spring type genotypes had high height and late maturity. High positive correlation between grain yield and plant height showed that genotypes with high plant height had higher grain yield under drought condition.

In order to investigate the effect of irrigation interval and harvesting time on agro-morphological traits of anise (Pimpinella anisum L.) a field experiment was conducted at College of Agriculture, University of Zanjan in the spring of 2011. The experiment was conducted as split plot based on a randomized complete block design with three replications. Main Factor was irrigation interval at three levels including every 7, 12 and 17 days irrigation and three harvesting times including harvesting at soft dough (waxy), hard dough and full maturity stages were assigned to the sub plots. The results indicated that the effect of irrigation intervals on majority of measured traits including number of umbrella in plant, number of seeds in main branch umbellet, number of seeds in sub branch umbellet, number of sub­-­branches in plant, number of umbellets in main branch umbrella, plant height, grain yield and biomass was significant. Majority of measured traits significantly decreased with increment in irrigation interval from 7 to 17 days. So, the highest biomass (1845.89 kg.ha-1) and grain yield (636.07 kg.ha-1) were obtained in 7 days irrigation interval and the lowest amount of the mentioned traits was observed in 17 days irrigation interval. Harvesting time had significant effect on some of traits including number of seeds in sub­-branch umbellet, biomass and grain yield. With delay in harvesting time from hard dough to full maturity stage, number of seeds in sub­-­branch umbellet, biomass and grain yield decreased, significantly. So, the highest biomass (1474.33 kg.ha-1) and grain yield (474.15 kg.ha-1) were obtained in hard dough stage and the lowest amount of the mentioned traits were obtained in soft dough stage.

Potato is one of the important vegetables which is tremendously getting damaged by Dikerya chrysanthemi causing soft rot during storage. In order to utilize lichens antibacterial potential to the disease management, five lichen species collected from Arasbaran region including Pleopsidium gobiensis, Ramalina sinensis, Parmelina tiliacea, Anaptychia setifera and Lecanora argopholis were extracted using ethanol, acetone and diethyl ether as solvents and bioassayed in laboratory condition by disc diffusion, minimal inhibitory and bactericidal concentration (MIC and MBC) methods. Pleopsidium gobiensis methanolic extract and Parmelina tiliace diethyletherextract were the most effective treatments against the bacterium with 7.9 and 6.6 mm of inhibition zone and 0.54 and 1.09 mg/ml of MIC and MBC, respectively. They were even more effective than Streptomycin which were used as positive controls. On the whole, P. tiliacea and P. gobiensis had the highest inhibitory effects on bacterial growth. In storage condition, spraying injured potato tubers with bacterial suspensionbefore or after selected lichens separate inoculations showed that all lichen treatments had protective and curative potential effects on bacteria, being able to save significant part of potato tubers from bacterial damage in comparison to the control. The most effective treatment was diethyl ether extract of R. sinensis applied after bacterial inoculation which could protect 91% of potato tubers from bacterial damage.

To investigate the effect of water stress on Euroflour hybrid of sunflower, an experiment was conducted in research field of Tabriz Branch, Islamic Azad University. Experiment was carried out as a randomized complete block design with three replications. Water stress levels were irrigation after 50, 100, 150, 200 and 250 mm evaporation from class A pan. Based on the results, grain yield decreased 25%, 29%, 42% and 51% at irrigation after 100, 150, 200 and 250 mm evaporation traetments in comparison to the control (irrigation after 50 mm evaporation), respectively. Besides, oil yield percentage reduced up to 30%, 36%, 54% and 62% at irrigation after 100, 150, 200 and 250 mm evaporation treatments compared to the control, respectively.Increasing water stress decreased head diameter, 100 seed weight, seed kernel weight, number of filled seeds per head, biomass, chlorophyll content, leaf area index, relative water content, and oil percentage. Water deficit, on the other hand, increased seed hollowness and stomatal resistance. So, Euroflour is a susceptible sunflower cultivar to water deficit and any delayed irrigation will decrease yield through decreasing 100 seed weight and number of filled seeds per head which are the most important components of grain yield in sunflower.

In order to study the effect of tuber inoculation with Azotobacter, super nitro-plus and super nitro biofertilizers on tuber yield of three potato cultivars (Agria, Satina and Kozima) in cold-semi-arid conditions, a factorial experiment was conducted based on a randomized complete block design in Tabriz, Iran. Results revealed that the tuber bio-fertilization with Azotobacter, super nitro-plus and super nitro caused a decrease of 34%, 28% and 26% in the tubers with diameter of smaller than 40 mm, respectively. bio-fertilization with Azotobacter increased the tubers percentage with diameter of greater than 60 mm in the three studied potato cultivars. Treatments with higher tuber number per plant showed lower tuber weight after the control. Biologic yield of potato was 22.5 t.ha-1 in the control and increased up to 18%, 14% and 12% in tuber bio-fertilization with Azotobacter, super nitro-plus and super nitro, respectively. Based on the results, 79%, 75% and 78% of tuber yield in biofertilized seeds with Azotobacter were suitable for seed or edible tuber production in Agria, Satina and Kozima cultivars, respectively. These values were 63%, 73% and 76% in biofertilized seeds with super nitro-plus, 74%, 66% and 73% in biofertilized seeds with super nitro, and 49%, 41% and 45% in the control, respectively. In conclusion, it is recommended that potato farmers biofertilize potato tubers before planting in cold-semi-arid regions.