Crop Production
Year:2010 | Volume:3 | Issue:1|Papers Count:15

Concinciding of wheat growth in post - anthesis period by water deficiency can result in reduction of current photosynthesis. In this circumstance stem - stored carbohydrate from pre - anthesis period had an important role in supporting assimilates for growing grain. An experiment was conducted in 2007-8 in experimental farm of Arsanjan Islamic Azad University, in order to investigation the quantity of stem reserves in different wheat cultivars of different height. The randomized block, split - plot design was used in the experiment. Main plots consisted of three irrigation regimes (full irrigation, only one irrigation in post - anthesis and without irrigation during post - anthesis period) and subplot consisted of six wheat cultivars (Marvdasht, Falat, Ghods, Karaj3, Adl and Kaveh). The results showed that water holding in post - anthesis period significantly reduced grain yield, biological yield, grain weight and stem weight. Grain yield, biological yield, harvest index, number of ear m-2, number of seed ear-1 and plant height significantly differed between cultivars. The interaction effects of cultivars and irrigation indicated that different cultivars respond differently to reduction of irrigation. By withholding post - anthesis irrigation the adverse effects of drought on grain weight and grain yield in tall cultivars was lower in comparison with dwarf cultivars. Losses of stem weight with irrigation withholding were higher in tall cultivars. These results indicated that tall cultivars have more stored reserves in stem, which can be used in unfavourable condition for grain filling. By the other word remobilization is higher in tall cultivars and this trait can be used for developing drought tolerance in breeding programs.

With increasing the world population, and needing to feed it, the yield enhancement of cereals crops is of the most important approaches meet this target, which is achieved via identifying the effective factors underlay yield of cereals like wheat. This experiment was conducted to evaluate the grain yield and its association with some contributed traits in a doubled-haploid (DH) wheat population comprising 100 DH lines deriving from across with maize, along with their parents (CK1 & ES32) and 6 Iranian local cultivars. Traits under study were of grain yield per unit area, number of fertile tiller and total number of tillers per plant, number of node, plant height, flag leaf length and width, spike length, number of grains per spike and 100-grain weight. The results indicated significant (P<0.01) correlations between grain yield with grain number per spike, spike length, and flag leaf length and width. According to stepwise regression analysis: spike length, number of tiller, flag leaf length, and number of grains per spike were the most important causing traits mostly (73%) interpreting the grain yield variation. The simple path coefficients analysis revealed that spike length and number of grains per spike contributed the most significantly (P<0.01) direct effects on grain yield. Moreover, the sequential path analysis showed that the number of tiller had a significant (P<0.01) positive direct effect on grain yield. In addition, there was significant direct effect of grain number on 100-grain weight and of spike length effect on number of grain per spike. Orthogonal contrast analyses results indicated also a nonsignificant difference between local cultivars and DH lines for the most important economic trait, yield. The results of this research could be applied for select the important yield contributed characters as selection criteria according to homogeneity of DH lines, and pave the way to potentially increase the yield of bread wheat cultivars.

To study of some cryoprotectives in cold tolerant rice genotypes (IRCTN33 and IRCTN34) and cold - sensitive rice genotype (Hoveize) were selected in previous experiment, fourteen - day rice seedlings exposed fourteen days in 13/15oC (respectively night - day) temperatures as the stress treatment and 22/28oC (night - day) temperature as control treatment in phytotrone. This experiment was conducted in factorial design with four replications. Results showed that the highest amount of stomatal conductance in stress treatment was in variety IRCTN33 and the lowest amount was in Hoveizeh (sensitive variety). Total Soluble Sugars (TSS) of leaves in stress condition was significantly more than control. The highest leaf TSS was measured in Hoveizeh variety, but TSS accumulation could not induce tolerance to low temperature at this sensitive variety. While, TSS of roots in control condition was significantly more than stress treatment and the lowest amount was in IRCTN33. Starch of leaves in control condition was significantly more than stress condition. Highest level of leaves starch was in Hoveizeh. Sucrose and fructose amount in stress condition were significantly more than control condition. Inorganic phosphate of roots in control was significantly more than stress. Osmotic potential of leaves in control was significantly more than stress. Lowest level of osmotic potential in stress condition was in Hoveizeh variety. Stomatal conductance had a high correlation with water potential and osmotic potential. Increase of sucrose and fructose in leaves, result in significant decrease of stomatal conductance. While, Increase of TSS of roots, caused increasing of stomatal conductance. In addition, low temperature stress caused decrease of photosynthetic capacity and some disorders in source-sink relations. TSS accumulation in sensitive variety Hoveizeh could not induce low temperature tolerance.

Sunflower (Helianthus annus L.) is the most important between oil plants in Iran. The objective of this study was to evaluate the effects of micronutrients application on the sunflower yield under drought stress. This experiment was carried out at Golmakan agriculture research station (Iran) in 2005 that using a split plot randomized complete block design with four replications. Irrigation was as a main factor at three levels (normal, low stress and high stress) and six micronutrient treatments were (control, Fe, Fe+Zn, Fe+Zn+Cu, Fe+Zn+Cu+Mn Fe+Zn+Cu+Mn+B) as sub plots within the main plots. Base fertilizers (N, P, K) and micronutrient treatments also used as required on the basis of the soil test. Results showed that the plant height, amount of chlorophyll in leaves, head diameter, seed per head and seed yield were significantly different between control and stress treatments. But irrigation treatments had no statistically significant effect on the flowering date, seed weight and oil percentage. Results also showed that micronutrient treatments increased the head diameter, seed per head, seed yield and oil percentage. Therefore, we confirm that under drought stress micronutrients application increases drought resistance in sunflower.

The effect of Tricyclazole application on waterlogging damage alleviation in canola seedlings was evaluated in a pot experiment in complete randomized design layout with three replications. Treatments included: control (no waterlogging), waterlogging, Tricyclazole plus waterlogging and tricyclazole. Tricyclazole (75%) applied at three - leaf stage on canola seedlings. Seedlings were exposed to waterlogging at five - leaf stage for 21 days. Results showed that waterlogging decreased survived seedling percent, plant height, leaf area, chlorophyll content, total dry weight, root/shoot ratio in comparison with the control. Application of Tricyclazole plus waterloggging increased leaf area, chlorophyll content, total dry weight in comparison with the control (1.38, 7.11 and 28.9%, respectively) and reduced plant height (12.9%). Tricyclazole plus waterlogging increased survived seedling percent, plant height, leaf area, chlorophyll content, total dry weight, root / shoot ratio in comparison with the waterlogged seedlings by 21.2 , 38.91 , 17.5 , 31.56 , 60 and 27.17%, respectively. Treatments had significant effect on survived seedling percent, number of dry leaf per seedling, total dry weight, shoot dry weight, stem dry weight, leaf dry weight, leaf area, width of widest leaf and chlorophyll content of canola seedlings (P<0.5). Root parameters; Taproot Length (TL), Root Area (RA), Root Volume (RV), Root Dry Weight / Root Volume (RDW/RV), Root Mass Density (RMD), Root Length Density (RLD), Dry Root Mass Density (DRMD), Root Diameter (RD) , Root Surface Area Density (RSD), Root Length / Root Fresh Mass (RF) were significantly differ (P<0.5) in treatments. It seems that the application of Tricyclazole prior to waterlogging, may alleviate the adverse effects of flash flooding in canola seedlings.

The objective of this study was evaluation of salt tolerance of elite forage sorghum lines in laboratory and field conditions. Salinity treatments were 5, 10, 15, 20, 25, 30 decisimens per meter in laboratory and distilled water as control. Lines were KFS1, KFS2, KFS3, KFS4, MFS1, MFS2 and LFS56. The lines also cultivated in saline and non saline field conditions during 2004-2005. Electrical conductivity of irrigation water was 2 and 11 decisimens per meter in non saline and saline conditions. Results showed that T50 (days until 50% germination) increased as salinity increased. The salinity threshold value at germination stage regardless to lines was 8.37 dS.m-1 with slop of 1.6%. Upon field experiment, the KFS2 line produced the maximum of 77.25 ton.ha-1 fodder yield in non saline condition, followed by KFS3 and KFS4 lines. The KFS3 line also produced the maximum fodder yield of 55.63 ton.ha-1 in saline condition. Total fodder yield of KFS2 line was 49.44 ton.ha-1 in this condition. At all, KFS3 and KFS3 are the sustainable lines on upon of susceptible and tolerant indices.

In order to evaluation the effects of different soil fertility systems on chickpea seed quality, field experiments were carried out in Sanandaj Agriculture Research Station of Iran in 2007 and 2008 growing seasons. Experimental units were arranged in split - split plots based on randomized complete blocks with three replications. Green manure levels considered main plots, base fertilizer compounds were considered subplots and blends of biofertilizers were considered sub-sub plots. Results showed that green manure increased seed nitrogen, phosphorus, magnesium, and manganese contents. Also green manure had a significant effect on grain yield, protein percentage and crude fiber. Application of organic fertilizers increased seed nitrogen, potassium, phosphorus, and magnesium contents. On the other hand, base fertilizers had a significant effect on chickpea seed sugars, starch and protein contents. Biofertilizers also had significant effects on seed quality traits. Interaction between green manure and basal fertilizers had a significant effect on grain yield, nitrogen, and magnesium and iron contact of seeds. The highest sugar, protein, starch and mineral elements contents were obtained from combined application of phosphate solubilizing bacteria and Trichoderma fungus. Simultaneous application of compost, farmyard manure and chemical fertilizer resulted in the highest seed nitrogen, potassium, phosphorus, magnesium, ciceritol, total sugar and protein contents. Thus in addition to improve seed quality, simultaneous application of chemical fertilizer, farmyard manure and compost increased grain yield and can reduce chemical fertilizers usage and can be useful on biological and ecological aspects.

Parameters recognize different area weather and climatic and effect on the plants one of the best important effect elements is increase products yield. Agro climatic study can state area ability and maximum exploit its. The aim of this research is, recognizing of the ability ecologic potential in different areas for cultivating Brassica napus In Regard To climatic temperature Needs in khorasan provinces. For the purport of general recognizing the region, climatic zoning was done by advanced Demarton method. The date of planting was determined with regard to suitable temperature (mean daily 15 - 20 centigrade) and Wibool formula (with 75 percent probability). The date of various phonological phases was estimated according to growth effected degree day. Climatic needs, optimum and limited temperatures in various phonological phases extracted from different sources and probability of occurrence calculated in the following studied areas. Relationship between main production and optimum and limited temperatures in various phonological phases. Then arrange and constitute temperature layer with used regressions formula. Planting regions classified in to four parts: very favorable (Torbat Haidarie, Ghoochan, Bojnord and Kholmakan), favorable (Birjand, Ghaen, Mashhad, Nishaboor and Ferdoos), relatively favorable (Sarakhs, Kashmar, Khonabad, Torbat Jam and sabzevar) and unfavorable (Boshrooye and Nehbandan).

The effects of plant densities (25, 35 and 45 plants m-2 as D1, D2 and D3 respectively), and inoculation with rhizobium bacteria (without rhizobium, with rhizobium and rhizobium + microelement application), on growth and yield were studied in chickpea (Cicer arietinum L.). Experiment was carried out in 2008 at Research farm of the faculty of agriculture of University of Mohaghegh Ardabil, a factorial experiment based on randomized complete block design with four replications. Effects of plant density on seed per pod and weight of seed-100 were no significant and on yield per plant and harvest index were significant. Effects of inoculation on weight of seed-100 were no significant and were significant on seed per pod, seed per plant and harvest index. Interaction effects of plant density and rhizobium inoculation were significant on secondary branch, pod per branch, and seed per plant and grain yield (kg ha-1). Highest grain yield per plant (3.6 g) and harvest index were obtained at D1 followed by D2 and D3 with 2.6 g and 35.79 %, respectively. Highest seed per pod, seed per plant and harvest index were obtained at R3 with 1.03, 3.8 g and 43.72 % followed by R0 as 0.86, 2.5 g and 33.91%. Maximum secondary branch at D1*R1 and D1*R2, and highest pod per branch at D1, D2*R2, and highest seed per plant at D1, D2*R2 and D3*R2 were obtained. However lowest secondary branch, pod per plant and seed per plant at D3*R0 and lowest pod per branch at D2*R0 were obtained. The highest and lowest grain yield (kg ha-1) were obtained at D3*R2 and D1*R0. Study of growth index show that increasing plant density and seed rhizobium bacteria inoculation+ microelement application were increased Leaf Area Index, Total Dry Matter, Crop Growth Rate, Relative Growth Rate and Net Accumulation Rate.

For identifying drought tolerance genotypes 29 wheat genotypes as cultivar factor and irrigation and non irrigation treatments as an irrigation factor in a split block design with 3 blocks were planted at a Research Filed of College of Agriculture, Tehran University, Iran. There was a low and non significant correlation (R=0.35) between yield at non irrigating (ys) and yield at irrigating (yp) condition. The low correlation implies the independence of yield at two conditions. For identifying tolerant genotypes the indexes of STI, TOL, SSI, MP, HARM, TI and GMP were used. The first two components explained 97% of variation. Based on the coefficients of components the first and second components were considering tolerance and sensitivity respectively. Using the biplot analysis genotypes Roushan, Inia, Kavir, Alvand, Ws-82-6, Ghods, Ws-82-9 and back cross of Roushan were identified as tolerant and Omid, Ghafghaz, Marvdasht, Navid and Tajan were detected as sensitive to drought.

In this experiment which was conducted at a field of Ramin Agriculture and Natural Resources University (Khouzestan, Iran) in 2005, the effect of molinate at 0 (weedy check), 2.16, 3.6 and 5 kg/ha and seeding rate of 100, 120 and 140 kg / ha was evaluated on the competition between rice and barnyard grass (Echinochloa crus-galli) in a split plot design with four replication. The interaction effects of herbicide and seeding rates on grain yield, number of inflorescence and number of grain per inflorescence were significant for both crop and weed. In weedy check, the crop grain yield at 120 kg seed / ha was significantly higher than the other seedling rates. In other hand, it was be observed that highest and lowest yield of crop and weed, respectively, was be related to 5 lit herbicide / ha. In this case, there was little difference between different densities. The rice yield in density 120 showed lesser changes in crop yield. In density 120, crop and weed yield relationship have lesser slope in comparison with other densities. Ultimately, it seems that optimum crop density can lessen crop sensitivity to other environmental and agronomic factors including weed competition and herbicide use.

In order to investigate efficacy of the integrated weed management in cotton fields, three experiments were carried out in three cotton growing areas of Iran, including Varamin, Khorasan, Fars in 2006. These experiments were conducted in randomized complete block design with 13 treatments and 4 replications. One of the pre plant soil mixtured herbicides (trifluralin 48% EC and ethalfluralin 33.3% EC) or a pre emergence herbicide (440g / kg Fluometuron + 440g / kg Prometryn), integrated with a post emergence herbicide (trifloxysulfuron sodium 75), or with a post emergence mechanical control (cultivator). The treatments were compared with hand weeding (weed free), weedy check and cultivator twice at using. Results showed that application of different herbicides together was more effective than using of them alone. Trifloxysulfuron sodium + trifluralin, trifloxysulfuron sodium + ethalfluralin and trifloxysulfuron sodium + (440g / kg Fluometuron + 440g / kg Prometryn) increased weed control and cotton yield. Cultivator + ethalfluralin and cultivator + (440g / kg Fluometuron + 440g / kg  Prometryn) were more effective than cultivator twice at using. Application of trifloxysulfuron sodium as a post emergence herbicide after application of a pre plant herbicide provided a good control of weeds.

Laboratory and field experiments were conducted to investigate the relationships between germination characteristics and field emergence in produced seeds of soybean cultivars as affected by under three different soil moisture conditions. The treatments are included water stress [Irrigation plants after 50 (Normal irrigation), 100 (Mild stress), 150 (Severe stress) mm evaporation from class A pan] and cultivar [Manokin, Williams and SRF×T3 Line]. Quality test was conducted factorial based on completely randomized design with four replications and field emergence factorial based on randomized completely block design with three replication. Results showed that in laboratory tests drought stress had significant effect on mean daily germination, seed viability and seed vigor. Experimental treatments had no effects on seedling emergence from sand in pot experiment and field condition. Germination in standard germination test had significant correlation with Germination in cold test. Seedling emergence in field had relationship with germination in standard germination test, cold test and accelerated ageing test and therefore can with using these tests predict field emergence.

Intercropping is considered for increasing and stability of yield in per unit. In order to evaluating the effect of corn / soybean intercrop in different planting dates, a study was carried out in Agricultural Sciences and Natural Resources, University of Sari, Faculty of Agriculture during 2005-2006. The experiment was a split plot design based on randomized complete block design with four replications in two years. The main plots were planting dates (A) at three levels; April 20 (a1), May 4 (a2) and May 19 (a3). Sub plots assigned to planting seed density at five levels: 8 rows of corn as control (b1), 2 soybean + 2corn rows (b2), 3 corn + 2 soybean + 3 corn rows (b3), 3 corn + 2 soybean +3 corn rows (b4) and 8 rows of soybean as control (b5). Results showed that the highest yield, seed numbers in m2, seed numbers per plant, seed numbers per ear and ear dry weight in corn, were obtained on may 19 in second year. Soybean yields were reduced significantly when intercropped with maize in both years. Yield, seed numbers per plant and per square meter in corn increased while in soybean decreased significantly as the number of rows of corn increased. The most Land Equivalent Ratio (LER), 1.37 was obtained in intercropping and b3 treatment. By increasing the rows of corn and decreasing that of soybean, LER was increased. Furthermore the results showed a beneficiary of corn / soybean intercrop.

In order to study the effects of sowing date and plant density on forage yield and some morphological characteristics of corn, an experiment was conducted in Gorgon Research station in 2008. In this experiment two sowing date (18 April and 21 June) and six plant densities (25000, 45000, 65000, 85000, 105000, and 125000 plant per hectare) were evaluated in form of factorial experiment (2×6) with a randomized complete block design. The results showed that height plant, stem diameter, silage yield, ear weight and crud fiber yield was under the influence of planting date and maximum silage yield and ear yield obtained in 18 April with 64900 and 20039 Kg / ha respectively. All of varieties under study were influenced by plant density. With increase plant density, stem diameter, ear diameter, ear length and ear weight decreased. Maximum silage yield, ear weight, crud protein obtained from 85000 plants per hectare. Therefore, for produce silage corn plant density would be lower of 85000 plant / ha.