AGRICULTURAL RESEARCH
Year:2005 | Volume:5 | Issue:1|Papers Count:6

Four chickpea genotypes including Bionij, Jam, F3 and ILC482 and two types of explants including epicotyl and mature embryo were selected for the induction of somatic embryogenesis. The best medium for the induction of embryogenesis -was MS medium containing 1mg/1 2,4,5-T and 1mg/1 2,4-D using mature embryos. The highest number of globular embryos were observed in MS medium containing 3mg/l 2, 4, 5-T. The maturity of embryos formed at different treatments was evaluated resulting that eight treatments showed various stages of maturity. Re-evaluation of 8 different treatments showed that the best condition for inducing mature globular embryos was ½ MS medium containing 6% maltose plus B5 vitamins. Full and half strength MS culture media containing 2, 4-D and 2, 4, 5-T and also without growth regulator were used for the regeneration studies. The results showed that the is MS culture medium without growth regulator was the most suitable medium for the beginning of regeneration.

Short-term changes of soil bulk density (BD), cone index (CI), corn (Zea mays L.) root length density (RLD) and root surface area (RSA) under different management regimes was studied. The interaction effects of tillage (no-till, NT; chisel plow, CP; and moldboard plow, MP) and composted cattle manure applications [0, 30, and 60 Mg (dry weight) ha-1] on BD, CI, RLD and RSA were assessed in a split-plot design under corn plants. The BD and CI were determined to depth of 22.5 and 30 cm, respectively. The RLD and RSA were measured to depth of 50 cm. Tillage methods and manure applications had significant effects on BD, CI, RLD and RSA. The MP system had higher values of RLD and RSA with lower values of both CI and BD. The NT system resulted in lower RLD, and higher CI and BD. The increased BD and CI of the topsoil in the NT treatment probably restricted root growth. Adding manure to the soil significantly increased RLD and RSA in the order of 60>30>0 Mg manure ha-1. There were also significant differences in CI and BD among the manure treatments. The positive effects on CI and BD of manure applications are attributable to manure incorporation in soil structural improvement. The results indicate short-term positive effects of manure application on soil physical properties under moldboard and chisel plowings in the semi-arid regions. Our findings indicate short-term beneficial effects of manure application on corn root characteristics while combined with the tillage systems.

This study was carried out to investigate the trend of change in agronomic traits (plant height, dry matter accumulation), chemical composition (DM, OM, CP, CF and ash percentage) and also in vivo nutritive value of Hamadan alfalfa at different cuttings and growth stages. Sampling was done in a three years old alfalfa field, the field was plotted on the basis of different growth stages (early blooming, full blooming, early flowering and full flowering) in a randomized complete block design. The results showed that at all growth stages, plant height in early cuttings was more than last cutting and the difference was statistically significant (P<0.05). Dry matter accumulation in second and third cuttings of a specific growth stage showed no significant difference, but, the difference between early cuttings and the last cutting \yas significant (P<0.05). Crude protein percentage of the whole plant decreased with the advance of growth stage but different cuttings taken at each specific growth stage showed no significant differences in this respect. There was an increase in crude fiber percentages of the whole bush, leaf and stem with the advance of age. The value of CF in second cutting from 19.1% at early flowering reached to 27.24% at full flowering. Also, crude fiber percentage of stem at each growth stage was significantly higher (P<0.05) in second cutting compared to third and fourth cuttings. Percentage of ash showed no significant changes between different growth 'stages and cuttings. Digestibility coefficients of all the nutrients and energy yielding value of alfalfa (on the basis of total digestible nutrients) decreased with the advance of growth stage. Digestibility of DM in second cutting decreased from 63.82% at early blooming stage to 60.0% at full flowering stage. Total digestible nutrients at early blooming stage in second, third and fourth cuttings was 0.63, 0.61 and 0.62 kg, respectively and at full flowering stage in both second and third cuttings it was 0.58 kg. It was concluded the with the progress in growth stage dry matter and crude fiber increase while crude protein and its energy yielding value decrease, but, the amount and the trend of this reduction vary at different growth stages. 

Evaluation of the effects of industrial wastewater on soil in terms of soil contamination and soil fertility is quite important. For study the effect of wastewater of the Shahid Moffateh Power Plant in, Hamadan, Iran, on losses of potassium and magnesium from soil, leaching experiment was conducted in soil columns. Soil samples were compacted piecemeal in the poly-vinyl chloride columns (9 cm in diameter and 25 cm height). The bulk density of columns reached to 1.4 g cm-3. Columns of the soils were leached using wastewater and distilled water as two treatments. Effluents were collected and concentrations of magnesium and potassium were measured in leachates. The experiments were continued until the concentrations of output and input cations became equal. The results showed that sodium ions in wastewater replaced magnesium and potassium ions from the exchange sites. The losses of potassium were in the range of 7-19 kg ha-1 (0.6-1% of initial exchangeable potassium). The losses of magnesium were in the range of 47-480 kg ha-1 (2.4-21% of initial exchangeable magnesium).

The leaching of potassium is affected by several factors such as soil texture, concentration of native potassium, amount and velocity of water in the soil and adsorption coefficient. This study was performed for evaluating the effect of soil texture and concentration of native potassium on leaching of potassium in four soil series (Yeknabad, Ahmadabad, Pamas and Hasanabad). The native soil potassium was leached with 10mM of CaCl2 solution. Also, the adsorption isotherm was conducted for evaluating the relationships between the adsorption coefficient and equilibrium concentration of K+ with the losses of potassium in soils. The results showed that after five and twenty pore volumes, the range of K+ leached from the soils were equal to 12-120 and 205-388 kg ha-1, respectively. The adsorption coefficients were in the range of 1.86-5.65 1kg-1. Using linear relationship between the leaching of K+ and the amount of leachate, the rates of potassium leaching were obtained to be in the range of 0.02 to 0.23 kg ha-l mm-l leachate.

The effect of seed priming on six wheat cultivars was investigated using Urea, NaCl and PEG 6000 as osmopriming agents and tap water and distilled water as hydropriming agents on emergence rate, germination percentage and base temperature of germination. Each osmopriming agent was included of five osmotic potential levels (-4, -8, -12, -16 and -20 bar) , three temperature levels (10, 15 and 20°C) and two time levels (12 and 24 hours) but hydropriming treatments were included of above mentioned temperature and time levels. In each solution and each cultivar the best combination of applied levels on the base of seedling emergence rate was selected and compared with other solutions and check (unprimed) treatment. In four cultivars Alvand, Sardari, Mahdavi and Chenab, urea osmopriming had the most significant increase on seedling emergence speed, final germination percent and seedling vigour index. In Chamran cultivar osmopriming with NaCl had the best results and in Pishtaz PEG solution was the best priming alternative. In cultivars Alvand and Mahdavi hydropriming treatments not only had no increase on measured factors but also significantly reduced final germination percent and seedling vigour index. In other cultivars except Sardari hydropriming has become apparent similar check treatment. Correlation among speed of emergence and germination percentage of the best priming treatment in all cultivars was significant. Also in another experiment the best osmopriming treatments in all cultivars caused higher germination speed at lower temperatures (ranging from 1°c to. 12°C) and generally reduced base temperature of germination by almost 1.3°C compared to control. It is concluded that seed priming treatments with urea solutions may serve as an appropriate treatment for advancing seedling emergence speed and germination uniformity of the cultivars studied.