Effects of salinity on growth indices and cation accumulation of eight wheat cultivars (Triticum aestivum)

Effects of salinity on growth indices and cation accumulation of eight wheat cultivars (Triticum aestivum

The effect of plant density and nitrogen fertilizer on light interception and dry matter yield in hemp (Cannabis sativa L.)

The effect of plant density and nitrogen fertilizer on canopy light interception and on flowering was investigated in hemp (Cannabis sativa L.) cv. ‘Kompolti’ Crop grown at initial densities of 50, 150 and 250 plants/m2 at the Mashhad and 30, 90 and 150 plants/m2 at the Shirvan. Nitrogen fertilizer was applied before and 45 days after sowing at a rates of 50 and 200 kg/ha at the Mashhad, and 50, 150 and 250 kg/ha at the Shirvan. Rate of canopy development increased with increasing plant density and nitrogen fertilizer in both sites. At the Mashhad, interception of 90% of light was attained at 380 to 665 degree days (base 2°C) from emergence for the crop grown at different densities. At Shirvan, rate of canopy development was slower. Interception of 90% of light was attained at 586 degree days from emergence for the crop grown at 30 plants/m2 and at 712 degree days for the crop grown at 150 plants/m2, probably as a result of cold weather. Nitrogen fertilizer in a similar way as plant density increased light interception. Maximum light interception did not depend on plant density and nitrogen fertilizer and was about 95%. In both sites, the flowering date was later with increasing plant density. Dates of 75% flowering for the initial densities of 50, 150 and 250 plants/m2 in Mashhad and 30, 90 and 150 plants/m2 in Shirvan were, respectively 26 August, 1, 6, 6, 11 and 12 September. Independent of plant density, canopy light interception started to decline at about 150 degree days after flowering, reaching 58 to 75% at about 700 degree days post-flowering. Morphological characteristics at both sites were highly correlated with plant sexual, plant population and nitrogen fertilizer. Highest stem, leaf and inflorescence yield were obtained in Mashhad at 250 plant/m-2 and in Shirvan at 150 plant m-2 when 200 kg N ha-1 in Mashhad and 250 kg N/ha in Shirvan was used. Above ground dry matter increased at both sites with increasing plant density and nitrogen supply. The results presented here can be used to account for the effect of a wide range of plant densities and nitrogen fertilizer for simulation of the course of light interception by a hemp crop

Germination characteristics and cardinal temperatures of lambsquarter, purselane and crabgrass

In order to study the cardinal temperatures of lambsquarter (Chenopodium album), purselane (Protulace oleracea), crab grass (Digitaria sanguinalis) and also predicting their emergence time within the fields an experiment was conducted in Weeds Research Labratory, Faculty of Agriculture, Ferdowsi University of Mashhad in 2005.The type of experiment was a completely randomized design with 9 treatment and three replications was used. Treatments consisted of 9 constant temperatures (5, 10,15,20,25,30,35,40 and 45°C) with 50 percent relative humidity and constant light radiation for 14 days. The germinated seeds were counted everyday and the rate of germination percentage, cumulative germination and cardinal temperatures were calculated. The cardinal temperatures including base temperature (Tb), optimum temperature (To) and cieling temperature (Tc) for lambsquarter was 4,29.5 and 43.3°C for purslane 11.8,35 and 49.3 °C and for crab grass it were 14.16,25/6 and 41.3°C respectively.The results indicated that lambsquarter with lower Tb and To is able to germinate when it is cooler and thus it will be dominant early in the season, Gradually , when the weather is getting warmer, purselane and then crab grass will dominate and invade the fields. On the whole, due to differences in physiologic of aspects and rate of weed growth the germination peak differs within fields. \ud \ud Keywords: Germination, base temperature, optimum temperature, cieling temperature

Spatial relationships between seed bank and seedling populations of Hordeum spontaneum and Cardaria draba in saffron (Crocus sativus L.) fields

Geostatistical techniques were used to characterize the spatial relationship between Hordeum spontaneum and Cardaria draba seedling and seed bank over the course of one growing season (2004-2005) in three saffron fields, located in Southern Khorasan, Iran. The density and spatial distribution of weeds varied widely with fields. The emergence percentage was higher for Cardaria draba than for H. spontaneum in all fields. Semivariograms showed spatial autocorrelation in seed bank and seedling populations of H. spontaneum and C. draba in all fields. Cross-semivariograms showed moderate to strong (63.3 to 94.7%) and strong spatial continuity (78.4 to 95.4 %.) between seed bank and seedling population densities of H. spontaneum and C. draba, respectively. Grey-scale field maps of C. draba seed banks corresponded visually to maps of seedling populations and could have been used to target control efforts, but visual correspondence between H. spontaneum seed bank and seedling maps was poor. Seed bank and seedling mapping may be useful for site-specific management, but additional information is needed to understand variation in the relationships between these two populations over time and space

Study of competitive effects of barnyardgrass (Echinochloa crus - galli) and redroot pigweed (Amaranthus retroflexus) on dry bean (Phaseolus vulgaris)

Study of competitive effects of barnyardgrass (Echinochloa crus - galli) and redroot pigweed (Amaranthus retroflexus) on dry bean (Phaseolus vulgaris

The effects of different nickel concentrations on some morpho-physiological characteristics of parsley (Petroselinum crispum)

Nickel as a heavy metal is considered a fatal and toxic element for humans, animals and plants. However, some plants are known as hyper accumulator for nickel and sometimes seem to be useful for plant growth. Thus, investigation on the effect of nickel on plants' growth is an issue of importance. In this paper, we have studied the effect of different nickel concentrations on parsley growth and morph-physiological characteristics and its effect on absorption of some macro elements in this plant. Seeds of parsley were germinated in germinator and seedlings were transferred to hydroponics culture. The seedlings were grown in Hogland solution with different nickel concentrations (in form of nickel nitrate) of: 0, 0.25, 0.5, 0.75, 1, 1.5, 2 and 4 ppm. A completely randomized design with 8 treatments and 7 replications per treatment was used. Twelve weeks after treatments, morph-physiological characteristics including SPAD number, plant biomass, length of shoot and root, leaf area, leaf number and stomatal resistance were measured. The amount of absorbed nickel in plant foliages and roots of different treatments were also measured. The results revealed that the application of different nickel concentrations were decreased SPAD number, plant biomass, leaf area and leaf number, but the stomatal resistance were increased. Increase of nickel concentration resulted increasing Ni concentrations of plant foliages and roots. Nickel with 0.75 ppm concentration or higher imposed a toxic effect on parsley as general wilting and significant reduction in most morph-physiological characteristics.\ud \ud Keywords: Hydroponics culture, parsley, Petroselinum crispum, Nickel

Effects of planting pattern and density) on growth indices, yield and yield component of corn (Zea mays) in competition with redroot pigweed (Amaranthus retrofelexus(

An experiment was conducted in 2002-2003 using split-split plot arrangement based on Rondomised Compelete Block Design with three replications at Feiz Abad Agricultural Research Station of Qazvin, in order to study of planting patterns and corn densitis effect in competition with redroot pigweed. Main plots inclouded two planting pattern of corn (P1: single row and P2: double row), sub plots inclouded two corn densities (D1:7 and D2:10 plant/m2) and sub sub plots inclouded 4 weed densities (C1:0, C2:2, C3:6, C4:12 plant/m2). Sampling conducted in 2-weekly intervals and growth indices evaluated. Results indicated that with increasing of weed density CGR, TDW, LAI, number of seeds in row, grain and ear yield decreased but plant height increased. Also LAI, CGR, TDW, number of weed seed and seed,s weight of weed increased. By increasing in corn density LAI, CGR, TDW, ear and grain yield increased, but length and diameter of ear and number of seeds in row decreased. Also LAI and CGR of weed increased, but TDW was decreased. In double row planting pattern just CGR, LAI, TDW of corn were higher significantly than single row planting pattern. But single row planting of weed caused higher LAI, NAR, RGR, CGR and TDW of weed in comparison with double row planting pattern. In 2-way interaction, double row planting pattern and zero densities and 2 weeds/m2 had highest grain yield respectively. There were no significant differences for 3-way interactions but double row planting pattern 10 plant density of corn/m2 zero weed/ m2 had highest grain yield

Allelopathic potential of shoot and corm of saffron residues on wheat, rye, vetch and bean

In order to evaluate effects of saffron residues on wheat, rye, vetch and bean, an experiment was conducted in Research Greenhouse of College of Agriculture, Frdowsi University of Mashhad, in 2005. The type of design was split factorial arrangement of treatment based on randomized complete block design with three replications. Main plots included of four crop species, wheat, rye, vetch and bean, and sub plots were saffron corm and foliage, and amount of saffron tissue added to the soil (4.25, 15, 30 and 75 g of grounded tissues in 1.5 kg soil). Results showed that source of saffron tissues and the amount of added tissue to soil, had a significant effect on some of the studied factors in four crops. With increasing the amount of saffron leaf tissue added to the soil, in compare with control, chlorophyll percentage, plant height, leaf surface area, shoot and root biomass were increased, but with increasing the amount of saffron corm tissue compare with control, all studied traits were decreased. Summer crops (vetch and bean) were affected by saffron corm and foliage tissues less than winter crops (wheat and rye). In conclusion, saffron corm and foliage residue had a pronounce allelopathic and promotive effect on the studied crops.\ud \ud Key word: Saffron corm, saffron foliage, leaf surface area, chlorophyll content, saffron biomass

Evaluation of droght tolerance of new wheat genotypes under water stress conditions

To evaluate the drought tolerance of new wheat genotypes to terminal water stress in field conditions, an experiment using a split plot design based on compelet randomaised block design with three replications was conducted in Torogh Agricultural Research Station (Mashad) in 1382-83. Irrigation treatments with two levels were allocated in main plots: I1- full irrigation (100% water use in different development stages) and I2- water stress (withdrawal of irrigation from anthesis stage to maturity with prevention of precipitation using mobile rain shelter). Number of 16 elite wheat genotypes suited for cold regions of Iran and Khorasan province (C-82) were allocated in sub plots. Results showed that, irrigation treatment had a significant effect on grain yield (GY), harvest index (HI), No. of spike per m2 (S.m-2), No. of grain per spike (G.S-1) and thousands kernel weight (1000 KW). There was significant differences between genotypes. C-82-5 was a high yielding genotype in both conditions (control and water stress) and had optimum level of HI, G.S-1 and 1000 KW. The tolerance of genotypes to water stress was evalovated with different drought tolerance indices, such as stress tolerance index (STI). Results showed that, C-82-5 was a high yielding genotype with more tolerance to terminal water stress