Journal of Agricultural Sciences and Natural Resources
Year:2007 | Volume:13 | Issue:SUPPLEMENT (SPECIAL ISSUE ANIMAL SCIENCE)|Papers Count:21

In order to study the effect of Mn and Zn micronutrients foliar application on yield and yield component of three winter safflower varieties, under drought stress, two field experiments were conducted in 2001-2002 and 2002-2003 in a farm located at 17 kilometer from west of Isfahan city.The experimental design was split factorial in basis randomized complete block with three replications. Main plots were different levels of drought stress included: S1 =full irrigation, S2=withholding irrigation in vegetative growth stage (from beginning of rapid stem development to pollination starting), S3=withholding irrigation in flowering stage, and S4= with holding irrigation in seed filling stage. Subplots were the factorial combination of four levels micronutrients foliar application treatments (F1= no foliar application, F2= foliar application of water, F3= 3000 ppm foliar application of Zinc Sulfate and F4= 3000 ppm foliar application of manganese sulfate) and three cultivars (C1= Zarghan 279, C2= Varamin 295 and C3= LRV 5151). In these experiments biological and grain yield, harvest index, days to flowering, days to maturity, number of head per plant, number of grain per head, Plant height and 1000-seeds weight were measured. Significant interaction effect between drought stress and foliar application on biomass and grain yield of cultivars showed that response of cultivars to foliar application was different in each level of water stress in two years. Mn and Zn foliar application compared to no foliar application could compensate the impact of stress on vegetative growth of safflower. Foliar application could not improve the grain and biological yield of safflower in flowering and pollination stage that was distinguished the most susceptible stage to drought stress. However, yield components, included number of head per plant, number of seed per head and 1000-seed weight, had positive response to Zn and Mn foliar application under drought condition at flowering stage. Significant positive correlation was found between yield and yield Components.

In order to evaluate the effect of sowing depth (3, 6, 9 and 12 cm) and temperature (10, 15,20,25,30, and 35°C) on emergence of chickpea, cv. Hashem, a pot experiment was conducted at Gorgan University of Agricultural Science and Natural Resources. Results showed that at all sowing depths, emergence percentage was constant for 10 to 32°C, but it decreased at higher temperatures. Emergence rate decreased with increased in sowing depth, but this decrease was higher at deeper sowing depths. It was found that at low temperatures, shallow sowing depth was better than deep sowing depth. The best results are obtained at 20 to 25°C and sowing depths of 3 to 6 cm. Therefore, it seems that under conditions of high temperature at sowing time, seeds can be sown deeper for better usage of soil moisture.

For studying the effect of different soil moisture levels (FC, %60FC, %70FC, %85FC) on growth indices, seed yield and yield components in lentil, an experiment was carried out in a factorial experiment with randomized complete blocks design with three replications in greenhouse. Irrigation levels were considered as the first factor and varieties (Ziba and Mardom) as the second factor. Moisture levels were applied in flowering initiation and soil moisture was kept in FC extent until this stage. In both varieties, relative growth rate (RGR) and net assimilation rate (NAR) in different moisture levels decreased when GDD increased.Highest seed yield, pod numbers per plant, seed number per pod, period of filling duration, days to ripening, and harvest index belonged to %60FC water level but they were not significantly different from that of %70FC water level. This process was also observed about some physiological traits such as leaf area index (LAI), dry matter (DM), and crop growth rate (CGR). Ziba variety had more leaf area index, dry matters, crop growth rate, seed yield, seed number per plant, period of pod filling and harvest index than Mardom variety. Most of the agronomical and physiological traits of lentil such as dry weight and leaf area index decreased in high soil moisture levels (%85FC and FC) because of irrigating pots once every two days and every day respectively, drain limitation of soil in pot rather than fIeld and susceptibility of lentil to high water in soil.

To study the effect of different nitrogen level (0, 50, 100 and 200 kg/h) and pruning of head (no prunning, prunning of head after formation of 10 and 14 nod) on yield and yield components of medicinal pumpkin an experiment was conducted in a randomized complete block design with factorial arrangement with 3 replication during 2004 and 2005 growing season of Research Factoryof Niack Medicinal plants Industry and Culture in Gorgan. Such as male and female flower, fruit and seeds per fruit number, mean weight of fresh fruits, weight of 1000 seeds, fruit and seed yield per hectare were measured. The results indicated nitrogen levels had significant effect on fruit number, mean weight of fresh fruits, weight of 1000 seeds, fruit and seed yield. The maximum fruit number per plant (2.74), mean weight of fresh fruits (2.61 kg), weight of 1000 seeds (160.36 g), fruit and seed yield (127 and 1.5 t/h) were obtained at nitrogen rate of 200 kg/h. Also the results indicated the prunning of head has significant effect on male and female flower, fruit number plant, fruit and seed yield. The maximum male and female flower number per plant (50.85 and 11.52 respectively), fruit number per plant (3.15), fruit and seed yield (99.88 and 1.3 t/h respectively) were obtained at prunning of head after formation of 14 nods. The results indicated nitrogen rate and prunning did not have significant effect on seed number per fruit. No significant difference was observed due to the intraction between nitrogen rate and prunning treatments with regards to all traits.

An experiment was conducted under controlled-conditions to investigate drought tolerance germination in cotton. Factorial combination of 40 cotton genotypes and 3 drought levels (-1,- 4 and-8 bars) were used in a complete Randomized block design 3 replications. Osmotic potentials were created using PEG6ooo. Germination components (rate, uniformity and total germination) were evaluated in Petri-dishes and seeding growth (root, shoot and total dry weight) in paper towels. Results showed that root shoot ratio increased with decrease in osmotic potential, the greatest root shoot ratio was obtained at - 8 bars. Other traits decreased with decrease in osmotic potential. Shoot dry weight showed the greatest decrease among the evaluated traits. The genotypes Tabeladia, Bulgar 433 andam early maturity mutant in germination test and genotypes Bulgar 433, Barbadens and Siokrain seedling growth test were detected tolerant to drought and genotypes temer-14, N.O. 259 and A.S.J.2 syland in germination test and A.S.J.2 x syland, Delta pine and 43221 in seedling growth test were found sensitive. These genotypes can be used in breeding programs of cotton for drought tolerance.

In order to study the effects of row spacing and seed rates on yield, yield components and seed oil percentage of three spring Canola (Brassica napus L.) cultivars, a farm experiment was conducted at the autumn of 2003 at Bay-Kola agricultural station, Mazandaran as a split split plot based on a1 randomized complete block design with four replications. The treatments were three row spacing (12, 18 and 24 cm) as main plots, two seed rates (4 and 6 kg/h) as subplots and three spring Canola cultivars (Hyola 401, RGS-003 and Hyola 60) as sub subplot. Results showed that increasing row) spacing decreased seed yield but not effected on other traits. The highest seed yield (3309.44kg/ha) was obtained by applying 12 cm row spacing. Increasing by seed rates from 4 to 6 kg/ha, number of pod per plant decreased, but other traits were not affected. The highest number of pods per Plant (98.06) was obtained by applying 4 kg/ha seeds. The Hyola 401 had better performance than other cultivars in all of traits (pod per main stem and per plant, seed per plant, seed yield and seed percentage). Interaction between row spacing with seed rate and with cultivar was significant only at number of pod per main stem. The lowest one was obtained by 24 cm row spacing with 6 Kg/ha seeds.The RGS-003 cultivar with 12 cm row spacing had highest pod per main stem, although Hyola 401 cultivar with 24 cm row spacing had highest one.

In order to study two grains filling characteristics (specific effective grain filling period and effective grain filling rate) to improvement of grain yield this study was conducted during 1999 and 2000 growing season in Koohdasht dry land Research Station in Lorestan Province. An experiment using complete randomized block design which ten rain-fed wheat (Triticum aestivum L.) genotyps treatments with four replications was used. Also, to determine correlation coefficients between triats, parameters were measured consist of grain yield, 1000 Kernel weight, harvest index, biological yield, straw yield, effective grain filling rate, test weight. Results showed that a significant positive correlation between grain yield with 1000 Kernel weight, Harvest index, biological yield, straw yield, effective grain filling rate test weight and with number of days, to steming was a negative significant correlation. Results of the growth grain process indicated that overall, at the end the linear of (Tr 8010200, Zagross) No. 4 and No.10 genotypes were the most final grain weight (40mg) and genotypes (Pik/opatacm, Maya 74 "s") No. 2 and No. 7 were the least final weight grain with 32 mg. Effective grain filling period were among genotypes 18.39 to 25.03 days. The most effective grain-filling period was 25 days related to No.10 (Zagross) genotype and the least No. 7 (Maya 74 "s") genotype with 19 days. Effective grain filling rate among genotypes were 1.43 to 1.74 mg.days-1. The most and the least effective grain-filling rate was for No. 2 (pik/opata) and NoA (Tr8010200) respectively. Between effective grain filling rate and period were significant negative correlation (r=-46 %**).

Increasing drought tolerance is one of the important breeding objectives. In order to evaluate the role of morphological traits on drought tolerance in cotton an experiment was conducted using a randomized complete block design with factorial arrangement of three soil moisture potentials (-1,-4 and -8 bars) and four cotton genotypes (Bolghare 334 of syndoze 80 as tolerant, and Narabrai and H.A.R as sensitive).There was 3 replications and 4 samplings at squaring, flowering, boiling and boil opening (harvest) growth stages. The experiment was conducted in a green house of Gorgan university of Agricultural Sciences and Natural Resources. Measurements were leaf temperature, plant height, node number, leaf number, the number of vegetative and reproductive branches, specific leaf area, and dry weight of aerial organs. Results showed that drought stress increases leaf temperature, but decreases stem height. Drought stress had no effect on the number of vegetative and reproductive branches Leaf number, leaf area and dry weight of aerial organs (leaf, stem, shoot) decreased by drought stress. Tolerant genotypes had greater plant height, node number, and leaf number and area compared to sensitive genotypes. In general, a collection of traits that were less affected by drought stress in both tolerant and sensitive genotypes can be used in breeding programs with the objective of enhanced drought tolerance.

To study the effects of four types of tillage implements and seed densities on the yield of rainfed wheat using deep drill grain with press wheel, an experiment was conducted in research farm of Gonbad Agricultural faculty in three years (1997-2000), using split plot with three replications in a Randomized Complete Block Design. In this research with four types of primary tillage implements namely: moldboard plow (MP), disc plow (DP), chisel plow (CP) and off set disc (OD) were used and Tajen wheat cultivar was planted using mentioned planting implements at the quantity of 140,150 and 160kg/ha. Crop yields for different treatments were harvested and measured. The results indicated that seed densities and tillage implements had no significant difference on the yield of wheat. However, reduced tillage has been proposed as a promising strategy to improve soil physical properties, soil erosion and moisture control, less energy consumption and greater speed for preparation of soil, expenditure reduction of production. According to the results of this research, application of chisel plows with 140kg/ha seed density is recommended to increase wheat yield in this region.

Inheritance of resistance to yellow rust disease in bread wheat was studied using a generation mean analysis. The study material comprised six generations (susceptible and resistant parents, F1, F2, BC1 and BC2) in two crosses. Seedlings were grown in greenhouse until the first leaves were fully expanded and then inoculated with two path types (race) of yellow rust (6E134A+ and 134E148A+) separately and infection type and latent period were recorded. Results of generation mean analysis and segregation ratios in F2 population indicated the significance of non-allelic interactions beside additive and dominant gene effects in inheritance of resistance to yellow rust. Dominant and dominant x dominant gene effects were significant in genetic control of infection type. The direction of dominance for infection type was different depending on the cross and the race in the experiment. Broad-sense and narrow-sense heritability of infection type were medium to high and medium respectively. Additive gene effect was significant in genetic control of latent period. Broad-sense and narrow-sense heritability of latent period were medium.

The modified version of model SUCROSI was recoded in QBASIC programming language for quantitative evaluating the effects of desired traits and soil conditions on rainfed spring wheat in Gorgan. Among tested traits, i.e. early maturity, late maturity, higher early growth, lower early growth, delayed stomata closure, early stomata closure, higher transpiration efficiency, deeper rooting, higher rate of remobilization of assimilates to the growing grain, lower rate of remobilization of assimilates to the growing grain, higher photosynthetic capacity and lower photosynthetic capacity, the traits higher early growth, late maturity and higher photosynthetic capacity found to be effective on consistent increasing the yield. There was statistically significant interaction between desired traits and soil conditions. The cultivar comprised with higher early growth could be cultivated in any soils. On the other hand, the cultivars that show late maturity and higher photosynthetic capacity should be cultivated in deeper and heavier soils. In despite of some reports that indicating the preference of coarse soils for dry farming, the results of current study indicated that the heavier soils are preferred compared to coarse soils. These results may be not applicable in other climatic conditions that should be evaluated.

In order to determine the effect of Medic green manure on yield of winter wheat and its compare with Azotobacter and Azospirillium biofertilizer impact, a study was conducted at the Dry land Farming Research Station of Ham University in 2003-2005. In this research that using randomized complete block design with 3 replicates, 8 crop rotations including 1-Medicago polymorpha-wheat,2- Medicago scutellata-wheat, 3-comparison 2 medic cultivars-wheat, 4-wheat-wheat +70 kg/ha N (conventional consumption), 5-fallow-wheat without N fertilizer, 6-fallow-wheat+biofertilyzer,7- fallow-wheat+biofertilizer+30 Kg/ha Nitrogen and 8-fallow-wheat+biofertilyzer+60 Kg/ha Nitrogen were compared. The rotations no. 4 and 5 were control treatments. In the second year of rotation the wheat grain yield in 8 treatments were ranked in 3 groups. In the first group only wheat +biofertilizer+30 Kg/ha Nitrogen treatment with 1570 kg/ha, in second group wheat without N fertilizer and wheat+ Biofertilyzer +60 Kg/a Nitrogen treatment with 1343 and 1293 kg/ha respectively, and in the third group wheat without N fertilizer and wheat with N conventional consumption treatment with 912 and 858 kg/ha respectively. And the other treatments were between the second and third group. The study indicates that using of control rotations as conventional sequences because of low efficiency and soil exhaustion are not profitable. But the medic-wheat sequence is recommended because medic positive effect on soil characters will increased in second year of rotation. Also in case dispensation a scientific managed on soil water conservation, weed control, protect of environment and sustainable agriculture, in follow year the follow wheat biofertilyzer+N30 rotation, as accepted sequence will be recommended.

In order to find essential information for efficiency management of field corn, a field experiment was conducted in 2001and 2002 at agricultural research center of Iranshahr. This research was laid out in a randomized complete block design arranged in a split plot with four replications for two years (2001-2002). Plant density (D1=70000, D2=80000, D3=90000 & D4=10000) were the main plot and planting patterns (p1=single row, p2=double row with 15cm space and p3=double row with 20cm space) were the subplots. Analyze variance of growth indices and dry matter trend accumulation was down on bias degree -days. Result showed in this study with increasing plant density up specific limit (90000 plant/ha) LAI, CGR and NAR increased. With double row, single row plant arrangement and in a many densities much and overlap shading because of leaf amount LAI, CGR, NAR decreased. With changing arrangement single row to double row due created cover more complete and produce farther LAI in rate light absorption, had one exist domination intercept this factor in necessary ground for will verticality maximization of CGR verticality As more space of content for each shrub and possibility access more light resources, water and nutrient special in season later have increased RGR. The biomes increased at all growth stage planting density of 100000 plants per hectare produced the highest biomes up the 1797 degree-days. There was not any difference between single and double row arrangement during early stage of growth but at later stage the difference was significant because canopyincrease and competition between the plants. Accumulation of grain dray matter was very fast at early growth stage but it happens slowly at later stage of growth since the photosynthetic source diminishes and translation material.

In order to study the effects of row-spacing and plant density on yield and yield components of three cultivars of soybean, an experiment was conducted as factorial in a randomized complete block design with 3 replication, at field is located about 22 kilometers west of Gorgan, in 2000. The factors that were examined in this study were row spacing (25, 35, 45cm), plant density (35, 45 and 55- plant/square meter) and soybean cultivars [Williams (a regional commercial soybean cultivar), Per *T1 and T1*SRF (promising soybean cultivars)]. The evaluated traits in this research were number of pods and seeds per plant, number of seeds per pod, seed yield per plant, hundred seed weight, total yield and harvest index. The results showed that cultivar had highly significant effect on number of pods per plant, number of seeds per plant, number of seeds per pod, hundred seed weight, harvest index and it had a significant effect on seed yield per plant and total yield. The cultivar of Per*T1 had the greatest pods number, seeds per plant, seed yield per plant and total yield. Although row-spacing has no significant effect on all traits that was evaluated, but the compression of means showed that number of pods per plant was affected by row-spacing and it increased as row-spacing increased. Also, plant density had a highly significant effect on number of pods and seeds per plant and seed yield per plant so that pods and seeds number per plant and seed yield per plant declined.

One of the important factors in crop management decisions in order to obtain high yield with optimum quality is plant density for different planting dates. In order to investigate the effects of delayed planting dates and plant density on yield and yield components in cotton (cv. siokra), an experiment was conducted in 2002 at Cotton Research Station of Karkandeh-Kordkoy. The experiment was a split-split plot in randomized complete Blok design with four replications. Three planting dates (May 15, May 31 and June 22) were allocated to main plotes, two row spacing of 60 and 80 centimeter and three plant distance of 10, 20 and 30 centimeter were levels of second and third factors, respectively. Results showed that with delay in planting date, yield and number of boll per square meter decreased but boll weight and number of seed per boll increased. Lower number of boll per square meter, more shedding of productive organs and low boll maintenance were the main reasons of yield reduction by delayed planting dates. The first plating date compared with the second and the third planting dates produced 25% and 58% more yield, respectively. There was a positive correlation between boll number per square meter and yield. Optimum plant density (plant density that had the greatest yield) was 13.8 plants per square meter for normal sowing date and 9 plants per square meter for the latest sowing date. For the second sowing date there was no response to planting date.

A field study was conducted at the main agricultural experiment station, Sari, Mazandaran in 1998 to evaluate the effect of various velvetleaf densities on soybean growth and yield. Various velvetleaf densities in soybean were compared in a randomized complete block design with four replications. The plots were four rows, five meter long. The soybean stand density was 20 plants/m. Treatments were: soybean plus velvetleaf at 0.25, 0.5, 1, 2, 4, 8 and 12 plants/m of soybean row; and control (weed free soybean). The lowest density of one velvetleaf plant/4m in soybean row caused 3.5, 14, 11, and 6.4 % reduction in height, canopy width, stem diameter and dry weight as compared to the soybean alone, respectively. Soybean pods number reductions were 9, 23, 33, 44, and 60. 75 and 83% for 0.25, 0.5, 1, 2, 4, 8 and 12 velvetleaf plants/m in the soybean row, respectively. Control treatment produced 2122 kg/ha soybean yield while plots infested with 0.25, 0.5, 1, 2, 4, 8 and 12 velvetleaf plants/m produced 1925, 1615, 1360, 1057, 922, 485 and 292 kg/ha, respectively. These results indicate that velvetleaf is very competitive in soybean, even at lowest density of one plants/4m of soybean row. Linear regression analysis showed a high correlation between number of pods (x) and soybean yield (y in kg/ha). The equation was: Y= 33.436 + 44.088x with r2=0.90.

Successful weed control of soybean using metribuzine needs to have sufficient knowledge about the response of different genotypes to this herbicide. The study of different genotype response to different dosages of metribuzine is an appropriate guidance in screening of suitable cultivars for cultivation. At first, this assessment was carried out in factorial experiment in form of complete randomized design at both pot and hydroponic experiments to obtain suitable dosages for separating cultivars. After it, the response of sixteen genotypes was studied based on selected herbicide dosages in both pot (split plot in form of complete randomized design) and hydroponic (factorial experiment in form of complete randomized design) experiments. Results of first experiment indicated that the best dosages for suitable screening of soybean genotypes in the pot experiment were 0.6 and 0.8 kgai/ha and in the hydrponic experiment was 0.5 mgai/l metribiuzin. Results of second experiment indicated that there was a corolation (r=0.68) between pot and hydroponic experiments and significant difference between soybean genotypes in degree of tolerance to metribiuzin herbicide. These studies indicated that Colombus, L17, Century and Hill genotypes were tolerant and CN210, M12 and Clark were sensitive genotypes.