مجله تولید و فرآوری محصولات زراعی و باغی
سال دوم شماره 1 (پیاپی 53، بهار 1391)

In order to evaluate the effect of seed priming on salinity modification of safflower (cv. Goldasht), a hydroponic experiment was conducted at Research Greenhouse of Vali-e-Asr University of Rafsanjan, Iran, in 2009. Priming treatments at 4 levels (no priming as control, and priming with distilled water, NaCl and Ca(NO3)2 for 24 hours) and salinity treatments at 4 levels (0, 8, 16 and 24 dS/m) were considered in a factorial experiment, based on complete randomized blocks design, with 4 replications. Results showed that chlorophyll content and K was significantly decreased with increasing salinity, while, proline, Na and Mg contents were increased with increasing salinity. Seed priming affected proline and Na contents and K/Na ratio significantly. The highest proline content (1.98 µmol/g fresh-leaf weight) was observed in NaCl pretreatment. The lowest Na (0.6%) and the highest K/Na (1.79) were observed in control and priming with Ca(NO3)2, respectively. Crop growth rate was reduced by 25, 33 and 55 percent in 8, 16 and 24 dS/m salinity levels, respectively, compared with control. It was concluded that proline and sugar content in shoots of this safflower cultivar increased in response to salinity, and seed priming with NaCl could modify salinity effects, especially net assimilation rate.

Unsuitable planting and weed competition are the most important factors that greatly reduce the yield of bean. In order to study the effect of planting date on yield and yield components of three white bean cultivars in weed infest and weed free condition a factorial experiment with randomized complete block design and three replications was carried out at Semirom in 2009. The treatments were planting date (May10, May 25 and June 9) and white bean cultivars (Shekofa, Pak and Daneshkade) and two levels of weed infestation (weedy and weed free). Results showed that planting date, weed competition and cultivars had significant effects on yield and yield components of white bean. The 30-day delay in planting date reduced the number of pods per plant, seeds per pod, 100 seed weight and biological yield of white bean cultivars, 22.5, 18, 20.1 and 22.5 percent respectively. Also weed competition, reduced the number of seeds per pod, 100 seed weight and biological yield respectively by 13.5, 5.7 and 27.1 percent. Result of planting date and weed competition interaction effects indicated that the weed competition decreased grain yield (53%) in third planting date more than others and delay in planting date was companion with increasing weed density and dry weight in flowering stage of bean. Also Shekofa cultivar had highest grain yield (3379 kg/ha) at the first planting date and weed free condition.

To investigate the effect of drought stress and plant density on yield and yield components of maize KSc 301 hybrid, a two-year study (2007-2008) was carried out in Varamin Agricultural Research Center by using strip split plot randomized based on complete block design in three replications. Four water stress levels (before flowering, during flowering and grain filling stage and no stress) were assigned as vertical factor and three plant densities (60, 75 and 90 thousand plants ha-1), were assigned made up of horizontal factor. The effects of water stress and plant density were statistically significant on yield and its components. Water stress at flowering stage reduced the grain yield by 42% compared to the control treatment. Water stress before flowering and grain filling periods, although yield was significantly lower than control but there was no significant difference between treatments. Reduce the number of grains per ear and increased the interval between the pollination of flowers until silking were the main reasons for reduced yield in the treatment of water stress at the flowering stage. Density of 75 thousand plants ha-1 was determined the best density for grain yield. Among the tested density, density of 90 thousand plants ha-1, compared to the control treatment had the greatest reduction in yield (25% reduction). Water stress and plant density interaction was statistically significant at 1% level. The highest and lowest grain yield, respectively, related to the 75 thousand plants ha-1 and without water stress (9100kg ha-1) and water stress at the flowering stage and 90 thousand plants ha-1 (3700 kg ha-1).Water stress at flowering stage, and densities of less than 75 thousand plants ha-1 or higher than 75 thousand plants ha-1 was significantly decreased harvest index. The results showed that the density of 75 thousand plants per hectare and avoid stress, especially at the flowering stage; appropriate yields can be expected from hybrid KSc 301.

Weed suppression and yield increasing are among the aims of intercropping systems. So, chickpea and barley intercropping was evaluated at the Agricultural Research Station, Faculty of Agriculture, University of Bu-Ali Sina during 2010 growing season. Experiment was conducted as split plot experiment based on randomized complete block design with three replications. Control (C) and non- control (NC) of weeds as main plots and six different planting patterns (T1; pure culture of chickpea, T2; pure culture of barley, T3; additive intercropping of 100% C + 100% B, T4; 100% C + 75%, T5; 100% C + 50% and T6; 100% C + 25% B) were considered as sub-plots. Based on results, traits were affected by treatments significantly. Maximum biological and grain yield of chickpea (695.87 and 249.88 g m-2, respectively) was obtained from CT1 treatment. Among intercropping treatments, the highest grain yield of chickpea (128 g m-2) and barley (506 g m-2) were achieved at CT6 and CT3 treatments, respectively. In comparison chickpea monoculture, all intercropping patterns decreased significantly biomass and density of weeds/m2. Also, in all intercropping treatments, LER was more than unit and maximum value of LER (2.40) was revealed at NCT3 treatment. In general, based on the results, additive intercropping of chickpea and barley can suppress weeds and increase land use efficiency.

Grass pea (Lathyrus sativus L.) is a crop which could substitute soybean in poultry ration in arid and semi-arid regions. To investigate the effects of sowing date and plant density on yield and yield components of grass pea, a factorial experiment based on randomized complete blocks design with four replications was conducted at Research Farm of Faculty of Agriculture, University of Birjand in 2008. Treatments included three sowing dates (March 5, March 21 and April 4) and four plant densities (30, 40, 50 and 60 plants per m2). Number of pods per plant, number of seeds per pod, number of seeds per plant, 100-seed weight, seed yield, biological yield and harvest index were measured. Results showed that by delaying the planting date, number of pods per plant, number of seeds per plant, seed yield and biological yield were decreased significantly. Maximum seed yield (2524 kg/ha) was achieved at the early sowing date (5th of March). These traits were increased with increasing plant density up to 50 plants per m2. But, increasing the plant density to 60 plants per m2 caused a decrease of these characteristics. Different planting dates and densities did not show any significant changes in number of seeds per pod, 100-seed weight and harvest index. Based on these results and the fact that Birjand is overwhelmed by an arid climate, planting grass pea at the first possible date at the end of winter with a moderate planting density (50 plants per m2) can lead to a reasonable seed yield.

In order to determination the effect of amount, efficiency and contribution of dry matter translated from different aerial organs, on grain yield in advanced wheat genotypes under normal and water stress after anthesis, an experiment carried out at agricultural and natural resources research station of Ardabil in 2008-2009. Eight advanced winter and facultative wheat genotypes compare with Shahriyar and C-80-4 were evaluating in two separated experiment under normal irrigation and after anthesis drought stress condition in a randomized complete block design with three replications. There were observed significantly differences among genotypes in term of remobilization parameters such as amount, efficiency and contribution dry matter on grain yield in both of normal and water stress experiments after anthesis stage. There were observed significantly interaction effects at almost of remobilization parameters between genotypes and water levels. The genotypes with 6 and 10 without different significant have the highest amount of dry matter translated to grain (10.2 and 10.4, respectively) under water stress condition, while there were observed the lowest value of this parameter under drought stress in genotypes with Shahriyar, C-80-4, 3 and 7. Maximum and minimum efficiency in DMT were obtained by genotype 6 in stress condition and genotype 7 under normal condition, also the genotypes with 6 and 10 without different significant had the highest contribution of dry matter translated total, whereas the lowest value of this parameter belonged to 7 genotype which obtained under normal condition. Lowest increasing percent for amount, efficiency and contribution of Dry Matter Translated related to Shahriyar and C-80-4 and highest increasing percent obtained from 4, 5, 6 and 10 Those are satisfactory for cold climates of Iran in terminal drought stress.

In order to investigate the effect of different ratios of ammonium: nitrate on the photosynthesis and fatty acid composition in canola (Brassica napus L.) under different levels of salinity, an experiment was conducted as a factorial based on complete randomize design at Agricultural Research Center in East Azerbaijan in 2010. The first factor was different ratios of nitrogen sources to ammonium: nitrate at four levels as 0: 100, 25: 75, 50:50 and 75: 25 and the second factor was two levels of salinity as 0 and 200 mM NaCl. Results showed that the highest fresh and dry weights, leaf area and relative water content (RWC), photosynthesis rate and potassium concentration in the leaves were obtained at ammonium: nitrate (50: 50) in non-saline condition. With increasing salinity, fresh and dry weights, leaf area, relative water content (RWC), photosynthesis and leaf potassium were significantly reduced. It seems that with increasing salinity the application of nitrogen (nitrate to ammonium) ratio of 50/50 caused less injure in crop. In treatments using high amounts of ammonium by canola, higher levels of fatty acids was obtained than feeding conditions with nitrate. The highest ratio of fatty acids was measured in saline conditions when the application of nitrate: ammonium was as 25:75.