Showing 30 results for Grain Yield
ِahmad Sobati, Abolhassan Hashemi Dezfuli,
Volume 2, Issue 2 (7-1998)
Abstract
Growth and grain yield of irrigated barley cultivars (Valfajr, Binam and Raihaneh) was investigated at 4 sowing dates (6, 22 Oct. and 14, 20 Nov.) in Karaj region. The effect of sowing date, genotype and their interaction on grain yield were statistically significant. Early and late sowing enhanced cold damage. However, the damage was more in late sowings. It was estimated that the optimum sowing date would be about 50 days (600 GDD) prior to freeze-up and maximum cold damage would occur when sowing was delayed until some 22 days (230 GDD) before freeze-up but any more delay in sowing would cause less damage. Highest grain yield was obtained from Raihaneh at 22 Oct. sowing. Binam showed good yield stability and relatively high yield, especially in unfavorable sowing dates. In the relatively favorable sowing dates (6 and 22 Oct.), grain weight showed positive correlation with linear grain filling rate, storage and translocation of reserves. LAI, LAR, RGR, CGR and LAD of each cultivar were higher in the second sowing date compared to the first one. The “ratio of post anthesis growth to maximum TDM” showed a high correlation with the harvest index. Raihaneh was the highest cultivar in resistance to lodging, harvest index, storage and retranslocation of assimilates, and linear grain filling rate. It is suggested that at favorable sowing dates, Valfajr and Binam had source limitation or disturbed translocation and Raihaneh had sink limitation.
M. Golabadi, A. Arzani,
Volume 7, Issue 1 (4-2003)
Abstract
Genetic variation of 300 genotypes of durum wheat comprising CIMMYT/ICARDA and Iranian germplasm was evaluated in 1999-2000 at Researh Farm of College of Agriculture, Isfahan University of Technology located at Lavark, NaJaf-Abad. Days to heading, days to maturity, plant height, spike length, grain weight per spike, number of grain per spike, number of spikes per m2, 1000-grain weight, test weight, grain yield, biological yield, and harvest index were recorded. Coefficients of correlation, step-wise regression, factor analysis and cluster analysis of characters and genotypes were conducted using the studied traits. Results indicated that considerable genetic variations exist for the traits and, in particular for grain yield, harvest index, number of spikes per unit area and number of grain per spike. Grain yield had a positive and significant correlation with days to heading, days to maturity, number of grain per spike and grain weight per spike. Factor analysis for the genotypes detected 6 factors, which explained 76.7 percent of the total variation among data. These factors basically involved potential of assimilate distribution, different aspects of plant storage, source-sink relationships, plant height and tillering potential. Cluster analysis was similar to factor analysis in grouping the characters. According to cluster analysis, the genotypes were calssified into 6 clusters with significant differences among all groups. Mean comparisons of traits in these groups showed that genotypes of groups 5 and 6 were superior in grain yield and harvest index and are beneficial to the local durum breeding objectives.
P. Ehsanzadeh, A. Zareian Baghdad-Abadi,
Volume 7, Issue 1 (4-2003)
Abstract
Planting density, through its impact on the level of available environmental factors may have significant impacts on grain yield in safflower (Carthamus tinctorius L.). In order to investigate the impacts of plant density on grain yield, yield components and growth characteristics of safflower, a randomized complete block design field experiment with four replicates was conducted in spring-summer, 2000, at Lavark Research Farm (Lat. 320 32, N and Long. 510 23, E), College of Agriculture, Isfahan University of Technology, Isfahan, Iran. Arak-2811 and Kouseh safflower genotypes were seeded at 16.6, 22.2, 33.3 and 50 plants/m2. For establishing these plant densities, plants were seeded in 12, 9, 6 and 4 cm distances, respectively, on ten 8-m-long rows spaced 50 cm apart in each plot. Plant density had no impact on plant growth stages with the exception of button formation. Genotype had significant effects on days to seedling emergence, button formation, and 50% flowering. While both number of days and accumulated growing degree-days for all growth stages decreased with an increase in plant density, Arak-2811 was earlier than Kouseh for most growth stages. Number of branches and heads per plant, number of heads per branch, number of seeds per head and harvest index showed significant decreases with increasing plant density. The decrease in the mentioned grain yield attributes was mainly negated by greater number of plants per m2, leading to no significant variation in grain yield between plant densities of the two genotypes. Arak-2811 produced a significantly greater number of heads per branch and 1000-grain weight however, these differences did not lead to any greater grain yield compared to Kousehdue, mainly due to the greater number of branches in the latter. Neither of the leaf area index, leaf area duration, and crop growth rate varied significantly with plant density and between two genotypes, suggesting no difference in dry matter production capabilities of the two genotypes under environmental conditions of the present study.
A. Mojiri, A. Arzani,
Volume 7, Issue 2 (7-2003)
Abstract
In order to study the effects of different levels of nitrogen fertilizer and plant density on grain yield and its components in sunflower, an experiment was conducted using 'Record' cultivar at the Research Farm of College of Agriculture, Isfahan University of Technology in 1996. Four levels of nitrogen (0, 75, 150 and 225 kg/ha) and four plant densities (65000, 75000, 85000 and 95000 plants/ha) were used in a split plot arranged in a randomized complete block design with three replications. Developmental stages, plant height, stem diameter, head diameter, number of head per m2, grain yield, biological yield, harvest index, 1000-grain weight, number of grains per head, grain oil percentage, oil yield and grain protein content were measured.
The results indicated that N fertilizer caused an extension of the growth period and means of days to physiological maturity. It also increased plant height, stem diameter and head diameter. While increasing plant density had an incremental effect on plant height, it negatively affected stem diameter and head diameter. N fertilizer up to 150 kg/ha increased the grain yield and biological yield, whereas higher levels of N fertilizer decreased both. Plant density of 85000 plants per hectare was observed as a suitable plant density, whereas the higher plant density had a negative effect on grain yield. N fertilizer via increasing the number of grains per head, and plant density via increasing the number of heads per unit area and also decreasing the number of grains per head influenced the grain yield. One-thousand grain weight was not affected by neither N fertilizer nor plant density. Considering the superiority of 150 kg/ha of N fertilizer and plant density of 85000 plants/ha for grain yield and oil yield, it appears that they could be recommended for producing desirable yield in the regions similar to the study region.
H. Sabori, A. Rezai, S. A. M. Mirmohammady Maibody, M. Esfahani,
Volume 9, Issue 1 (4-2005)
Abstract
An experiment was conducted at Rasht Rice Research Institute, in 2001 to study trait relationships and to determine the direct and indirect effects of different characteristics on grain yield of rice (Orgza sativa L.). A 9x2 factorial experiment in complete randomized block design with 3 replications was used. The two factors were 9 cultivars, namely: Hashemi, Ali Kazemi, Binam, Sepeedroud, Nemat, Khazar, Taichung, Chanto, and Usen, and 2 planting patterns (15x15 cm and 30x30 cm). Significant differences were detected among cultivars, between planting patterns, and their interaction effects. The direct effect of the number of panicles/m2 on grain yield was positive and significant in both planting patterns and their combined analysis. Heading date had a positive and significant direct effect on the number of panicles/m2 in both planting patterns and their combined analysis. Only in 30x30 cm planting pattern, a positive correlation was found between biomass at heading date and the number of panicles/m2. Grain weight per plant had a direct and positive effect on panicle weight in the 3 cases studied. Also, in all the cases studied, flag leaf area had positive direct effects on grain weight per plant. Grain filling rate and effective grain filling period increased in 30x30 cm planting pattern. Native cultivars demonstrated longer latent period. Grain filling rate and effective grain filling period showed positive direct effects on grain yield in both plantings. According to the results obtained, an increase in the number of panicles/m2, rate of grain filling, and effective grain filling period would enhance grain yield. Selection for heading date, grain yield per plant, and flag leaf area would also indirectly increase grain yield.
B. M. Ashour, A. Arzani, A. Rezaei, S. A. M. Mirmohammady Maibody,
Volume 9, Issue 4 (1-2006)
Abstract
The Genetic basis of grain yield and related characteristics were studied by a generation mean analysis in five crosses of winter wheat (Triticum aestivum L.). “Roshan”, “Mahdavi”, “Inia”, “Atila” and “Goscoyin” cultivars along with their F1, F2, BC1 and BC2 populations were evaluated by a split-plot design with crosses as the whole plot in a randomized complete block design with two replications and generations were applied as the subplots. Analysis of variance revealed significant differences among generations for studied characteristics including the grain yield per plant, the number of spikelet per plant, the number of spikelet per spike and grain weight per spike. For the majority of traits and crosses, F/DH1/2 was less than one, indicating that the sign and magnitude of gene actions were different. Estimates of broadsense and narrow sense heritabilities were low for the grain yield per plant compared with other traits, rating from 28.5% to 58.6% and 24% to 48,5% for the five crosses, respectively. Genetic components of generation means were calculated by fitting different models and choosing the best model indicated that the impact of additive, dominance and epistasis genetic components in controlling the traits depend on the cross and the trait under study.
N. Farid, P. Ehsanzadeh,
Volume 10, Issue 1 (4-2006)
Abstract
A major source of photoassimilates deposited into the seeds is the closest photosynthetic source to the latter sinks. While the contribution made to grain yield by floral parts and the adjacent photosynthetic surfaces has been determined for a number of crop plants, such information lacks regarding safflower. Thus the present study was aimed at estimating the contribution of photosynthesis of safflower head and the two adjacent leaves to the grain yield of this oil seed crop. A 4-replicate RCBD field experiment was conducted at Lavark Research Farm, Isfahan U. of Tech., using four genotypes (Nebraska10, Kouseh, Arak2811 and K12) and three levels of shading (heads only, heads and the two adjacent leaves and control) on safflower heads following pollination, using khaki paper bags. Genotypes differed in terms of days to heading and maturity, height, number of heads per plant, number of seeds per head, 1000-seed weight, seed weight per head and grain yield per plant. Shading on safflower head and the two adjacent leaves led to a significant decrease in number of seeds per head, 1000-seed weight, seed weight per head, grain yield per plant and harvest index. There was not a significant difference between the two levels of shading treatment. It could be concluded that, with the environmental conditions experienced during spring 2003 at Isfahan, the photosynthetic products of safflower head and the two adjacent leaves may contribute to grain yield per plant by as much as 37 percent.
S. Sharif, M. Saffari, Y. Emam,
Volume 10, Issue 4 (1-2007)
Abstract
Many experiments have been carried out to alleviate the negative effect of drought stress and to obtain suitable growth under water deficient condition. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. In a greenhouse experiment using a completely randomized block design with 4 replications at Kerman University Agricultural Department, the effect of 4 drought levels 25, 45, 65, 85 percent of field capacity and 3 different concentrations of chlormequat chloride 0, 1500, and 3000 mg/liter on some factors of winter barley cultivar Valfajr was investigated. Results indicated that increasing the cycocel concentration from 0 to 3000 milligram per liter leads to significant decrease in plant height. Relative water content affected by growth retardants was increased. Numbers of tillers and root and shoot dry weight, were also decreased because of applying cycocel in dry condition. The result also indicated that the root/shoot dry weight ratio, grain number per ear and ear number in dry condition without stress would increase using cycocel treatment.
Y. Emam, A.m. Ranjbar, M. J. Bahrani,
Volume 11, Issue 1 (4-2007)
Abstract
Drought stress is one of the major limiting factors of crop yield. A field experiment was conducted to study the effects of drought stress on yield and yield components of nine bread wheat and one durum wheat genotypes during 2003-2004 growing season. The experiment was designed as two separate randomized complete blocks design with three replicates under well-watered and unwatered conditions during the post-anthesis period. Post-anthesis drought stress reduced the grain yield and yield components in all genotypes. Mean of each trait significantly(p≤%5) decreased under drought stress conditions, except for spikeletes number per spike and ear number per square meter. The highest yield loss was caused by the grain number per ear and 1000- grain weight reduction under drought stress conditions.“Gahar” genotype had the highest grain yield (4149 kg/ha) under drought stress conditions, whereas the highest grain yield (6674 kg/ha) was obtained for “Nikenejad” genotype under optimum conditions. Based on stress susceptibility index, “Koohdasht” and “Boholh-15” genotypes showed the lowest and the highest yield loss in response to drought stress, respectively. Correlation analysis of yield and yield components indicated that, under drought stress conditions, ear number per square meter (r=0.751) and biological yield (r=0.707) had the highest correlation with the grain yield(p≤%5), whereas these traits were grains number per ear(r=0.864) and biological yield (r=0.848) for the well-watered conditions. Therefore, it might be possible to select genotypes for greater grain yield with the means of the traits which have the highest correlation coeficient with the grain yield under each moisture regime. Generally, it appeared that “Gahar”and “Nikenejad” genotypes with greater yield potential might be recommended for agronomic conditions similar to the present investigation.
P. Sharifi, M. Tajbakhsh,
Volume 11, Issue 41 (10-2007)
Abstract
To evaluate the effect of plant density and detopping on grain yield, protein content biological yield harvest index, growth indices, number of cob in each plant, No. of row per ear, No. of grain in each row, thousand seed weight of corn (Zea mays L. ar. SC 704), an experiment was conducted at the experimental statues of Research Center of Uremia Agricultural College in 2004. The Treatment design was split plot in randomized complete block design with four replications. The main plots included plant density at three levels (53000, 66000, and 88000 Plants/ha) and the subplets comprised three levels: (1) no detopping (control) (2) removing canopy only and (3) removing canopy and three leaves above the node. Analysis of Variance of data showed that both detopping treatment and plant density influenced the number of kernel per ear ,1000 grain weight, ear weight, total dry weight of biomass, seed yield and harvest index. Canopy detopping led to a marked increase in photo assimilateion import grains. The highest plant density evaluated, 88000 plants per hectare with detopping of three above leaves had the highest number of cobs per square meter. In plant density of 53000 plants per hectare and canopy detopping treatment, the number of grain per ear was greater than other densities. The efficiency of harvest index increased under corn detopping compared with control, and this increase with an increase in photosynthesis contributed to grain yield. It was concluded that major increase in grain yield under high plants density and tassel detopping was due to improvement of physiological indices.
M. Fazlalipour, B. Rabiei, H. Samizadeh Lahiji, H. Rahim Soroush,
Volume 11, Issue 42 (1-2008)
Abstract
Application of selection index for screening desired plants based on complex quantitative traits can be more effective than direct selection. This study was conducted using an F2 rice population consisting of 87 plants derived from a cross between two cultivars Gharib and IR28. The purpose was to establish suitable selection indices for increasing yield and its related traits in research farm of Rice Research Institute of Iran (RRII), Rasht, in 2005. Studied traits included the days from sowing, germinated grain to maturity (MD), plant height (PH), panicle length (PL), flag leaf length (FL), flag leaf width (FW), number of panicles per plant (PP), number of grains per panicle (GP), number of spikelets per panicle (SP), 100-grain weight (GW), grain yield per plant (GY), biomass (BM), harvest index (HI), grain length (GL) and grain breadth (GB). Among the studied traits, 100-grain weight (GW), biomass (BM) and harvest index (HI) (0.99) and flag leaf width (FW) (0.35) showed the highest and lowest broad-sense heritability, respectively. Path coefficient analysis revealed that BM, HI, GP had positive direct effects on GY. Calculation of five different selection indices based on optimum and base indices indicated that selection for BM, HI and GP using genotypic path coefficients and their heritability as economic values would be a suitable selection criterion for improving population. Moreover, this study showed that both optimum and base indices show the same genetic progress for the studied traits. Since evaluation of base index, is much easier than the optimum index, it is highly recommended.
M.r. Tadayon, Y. Emam,
Volume 11, Issue 42 (1-2008)
Abstract
Photosynthesis and wheat grain yield responses to supplemental irrigation with different amount of applied water under dryland conditions were investigated. Therefore, a two-year field experiment was conducted research farm of College of Agriculture, Shiraz University during 2004-2005. Five levels of irrigation including dryland conditions, irrigation at stem elongation, booting, flowering and grain filling were main plots and two wheat cultivars: Agosta and Fin-15 were subplots, and three rates of nitrogen including zero, 40 and 80 kgha-1 were sub sub-plots. The results showed that in both years, photosynthetic rate, stomatal conductance, substomatal CO2 concentration and transpiration rate, were significantly higher under irrigation at stem elongation stage compared to other supplemental irrigation treatments. In all of the four supplemental irrigation treatments, photosynthetic rate, stomatal conductance, substomatal CO2 concentration and transpiration rate decreased with decreasing the amount of applied water to each plot. In both years, the highest grain yield was obtained from supplemental irrigation at stem elongation stage, and the lowest yield was harvested at dryland conditions. The highest photosynthetic parameters, yield and yield components were obtained from interaction of supplemental irrigation at stem elongation stage × Fin-15 and 80 kg N ha-1 in both years. The supplemental irrigation in 2004 and 2005 increased the grain yield 200 and 221 percent, respectively, compared to dryland conditions. Thus, supplemental irrigation at sensitive stem elongation stage could affect significantly wheat grain yield of rainfed wheat cultivars and provision of adequate water for a supplemental irrigation at the appropriate growth stage could double the grain yield of rainfed wheat.
E. Farahani , A. Arzani,
Volume 11, Issue 42 (1-2008)
Abstract
An experiment was conducted to investigate the heterosis in 12 F1 hybrids of durum wheat using agronomic and morphological traits. Parents were selected according to the estimated genetic distances based on the results of a two-year field experiment, which were then crossed to produce F1 hybrids. Twenty-three genotypes (including 11 parents and 12 hybrids) were evaluated using a randomized complete block design with three replications Research Farm of College of Agriculture, Isfahan University of Technology, located at Lavark, Najaf- Abad in 2003. Agronomic characteristics comprised days to 50% flowering, days to 50% pollination, days to maturity, plant height, spike length, grain weight per spike, number of grain per spike, number of spike per m2, 1000-grain weight, biological yield, grain yield and harvest index. The results of analysis of variance showed significant differences among parents F1 hybrids and parents vs. crosses for all the studied traits. Substantial differences in the level of heterosis for plant maturity were detected among the hybrids with the highest heterosis belonging to HPI40100×PI40099 and HEupoda6× Chahba88 hybrids. Furthermore, superior hybrids included HAltar84/Ald×Chahba88, HBuchen7×Chahba88 and HEupoda6×Mexi75/Vic possessing the highest heterosis for grain yield and grain yield components among 12 hybrids of the present experiment. Eventually, it is concluded that Eupoda6, Odin12, Altar84/Ald and 45063Karaj genotypes when crossed with Mexi75/Vic genotype as well as Buchen7 and Altar84/Ald genotypes when crossed with Chahba88 genotype produced superior F1 hybrids.
M. Dehghanian, M. Madandoost,
Volume 12, Issue 45 (10-2008)
Abstract
In order to investigate the effect of zinc - chelate on drought tolerance of Azadi cross wheat, a randomized complete block design was conducted as split plot with three replicates in the Kherameh during 1383 - 1384. The main plot was four drought levels (control and drought stress in the stages of flowering, seed milk stage and two phases, together), and sub plot was zinc - chelate rates 0, 5, 10 & 15 kg per hectare. The results showed that zinc application under drought conditions increased spike per square meter significantly at the 5% level. Drought stress decreased 1000 - seed weight. Least of 1000 - grain weight was in two phases of flowering and seed milk stage together (29.78 g). The application of 15kg zinc -chelate fixed 1000 - seed weight. Treatments of drought stress decreased seed yield significantly (14.17% in the proportion of control), but zinc - chelate application increased wheat tolerance to seed yield decrease. Zinc - chelate application prevented from seed number decrease per wheat spike under drought conditions that was caused to tolerance of seed yield and harvest index decrease. The application of 15 kg zinc - chelate increased harvest index in comparison of control amount of 22%.
M. Bayat, B. Rabiei, M. Rabiee, A. Moumeni,
Volume 12, Issue 45 (10-2008)
Abstract
To study relationship between grain yield and important agronomic traits of rapeseed in paddy fields as second culture, fourteen varieties of spring rapeseed were grown in a randomized complete block design of experiment with three replications at Rice Research Institute of Iran, Rasht, during 2005-2006. Analysis of variance showed that there were significant differences between varieties for most of traits. Broad sense heritability ranged from 0.29 for pod length to 0.99 for days to maturity. Phenotypic and genotypic coefficients of variation for days to maturity and the number of pods in secondary branches were the lowest and highest, respectively. Moreover, genetic advance with 5% of selection intensity varied from 3.68% (0.25 cm) for pod length in main branch to 31.48% (915.58 Kg.ha-1) for grain yield. Results from genotypic correlation coefficients demonstrated that there were positive significant correlations between grain yield and the number of secondary branches, the number of pod in main and secondary branches, pod length in secondary branches, pod diameter in main and secondary branches, 1000-grain weight and oil percentage, and negative significant correlations between grain yield and days to 90% of flowering and days to maturity. Path analysis on genotypic correlations for grain yield as a dependent variable and the other traits as independent variables showed that the 1000-grain weight and the number of pods in secondary branches had the highest direct effects and days to 90% of flowering had low and negative direct effect on grain yield. Therefore, indirect selection for increasing 1000-grain weight and the number of pods in secondary branches are recommended for improving grain yield in rapeseed as second culture in paddy fields.
M. R. Tadayon,
Volume 12, Issue 45 (10-2008)
Abstract
In order to investigate the effect of sugar plant effluent on shoot solute percentage, yield components and grain yield of two wheat cultivars, a two year field experiment was conducted on a farm near Eghlid sugar plant during 2004-2005. Treatments consisted of two wheat cultivars (Alamot and Zarin) and two irrigated treatment: irrigation with effluent and irrigation with spring water (control). The statistical design was a completely randomized factorial with three replications. The results showed that under effluent treatment, nitrogen, phosphorus and calcium percentage increased in shoot, and Fe, Mn, Zn, Cu and B concentration decreased. However, effluent treatment had not any significant effect on K, Mg and S concentration. The results showed that N percentages in Alamot and Zarin cultivar under control treatment were 2.41 and 2.54% and under effluent treatment were 3.28 and 3.41%, respectively. P percentages under control treatment were 0.42 and 0.47% and under effluent treatment were 0.46 and 0.51%, respectively. Ca percentages under control treatment were 0.29 and 0.32% and under effluent treatment were 0.46 and 0.51%, respectively. In both years, the lowest number of tiller, number of spike, number of kernel per spike, thousand kernel weight, grain yield and harvest index were obtained from effluent treatment in the two wheat cultivars whereas this reduction was higher in Alamot than Zarin cultivar. In Alvand and Zarin cultivars, the lowest number of tiller per plant with 2.33 and 2.50, number of spike per plant with 1.83 and 1.92, number of kernel per spike with 31.67 and 32.50, grain yield with 5233 and 5532 kg ha-1 and harvest index with 32.03 and 33.53% and water productivity with 0.72 and 0.75 kg m-3 were respectively obtained from effluent treatment compared to control. Thus, the results showed that using sugar plant effluent could decrease grain wheat quality and wheat grain yield.
A. Moradi, A. Ahmadi , A. Hossein Zadeh,
Volume 12, Issue 45 (10-2008)
Abstract
Drought is a major factor limiting growth and development of crops such as mung bean (Vigna radiate (L.) wilczek) in arid and semi-arid regions of the world. This study was conducted to investigate the effects of different timing and severity of drought stress on physiological traits of mung bean and its relation to grain yield. A field experiment was carried out during 2004 growing season at Experimental Farm of Agriculture College, University of Tehran, Karaj, Iran. The treatments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Plants were exposed to moderate and severe water stresses at either vegetative (VS) or reproductive stages (RS). Physiological traits were measured at the end of vegetative and the middle of pod formation. Generally water stress reduced leaf net photosynthesis rate, stomatal conductance and leaf relative water content at different growth stages. The effects of RS treatments were more severe than that of VS one. Severe VS treatment increased photosynthetic water use efficiency, whereas RS treatments decreased it significantly. However, leaf area index and total dry matter were more responsive in VS compared to RS treatments. VS treatments did not affect harvest index, while RS treatments reduced it significantly. Drought stress also reduced grain yield by 9 and 49 % (relative to control plants) in severe VS and severe RS treatments, respectively. Therefore irrigation is critical during reproductive stage mainly because of the higher demand for photoassimilate. It is concluded that to maximize mung bean grain yield in arid and semi-arid areas, appropriate watering should be practiced across all phenological stages in general, and during reproductive stage in particular.
M Babaeian, M Haydari, A Ghanbari,
Volume 12, Issue 46 (1-2009)
Abstract
In order to study the effects of foliar micronutrient application under water stress at three stages of growth on proline and carbohydrate concentrations, grain yield and yield components of sunflower (Alster cultivar), a field experiment in split plot design with three replications was conducted in 2007. Alster cultivar was considered under water stress at three stages of growth (heading, flowering and grain filling) as main plot and seven micronutrient treatments, Fe, Zn, Mn, Fe+Zn, Fe+Mn, Zn+Mn and Fe+Zn+Mn, as sub plots. Results showed, water stress at three stages of growth significantly decreased grain yield, biological yield, 1000 weight seeds, cap diameter and cap weight of sunflower (Alster cultivar). The impact of water stress was more pronounced when applied at grain filling. Use of foliar micronutrient increased grain yield in water stress. On the other hand, use of Mn foliar application had the highest positive effect on yield components and grain yield. Free proline and total soluble carbohydrate concentration were increased under water stress at all of the three stages of growth. The highest concentration of these two components was found on the flowering stage. Foliar micronutrient also increased accumulation of the two components.
A Ahmadi, M Jodi, A Tavakoli, M Ranjbar,
Volume 12, Issue 46 (1-2009)
Abstract
The objective of this study was to evaluate some morphological characteristics associated with grain yield potential on 20 bread wheat cultivars under two irrigation and drought stress conditions. The experiments were conducted at Research Farm of Agriculture College, University of Tehran, Karaj during 2001-2003. Twenty bread wheat cultivars were planted as subplots within each irrigation main plots in randomized complete block design with 3 replications. Drought stress was imposed at the end of flowering, and plants were re-watered when they showed signs of wilting, particularly during the morning. The results showed that the interactions between cultivars × year and cultivars × irrigation were significant for the grain yield. The cultivars showed significant differences in grain yield under drought stress condition in 2001-2003. Roshan, M-79-4 and Alvand in 2001-2002 and Azadi, Marvdasht and M-79-17 in 2002-2003 were most productive under drought stress condition, whereas C-79-12, MV-17 and Shahpasand in 2001-2002 and M-79-4, Roshan and Nicknajad in 2002-2003 performed visa versa. Correlation between grain yield and measured traits under irrigation condition was different from drought stress condition, suggesting that grain yield controlling mechanisms operate differently under these conditions. Drought stress caused a reduction in 1000 seed weight of cultivars. High 1000 seed weight and high grain number per ear were accompanied by high grain yield in drought stress and irrigation conditions, respectively. In the present study, clear relationship between grain yield and ear length was not observed.
Z Daneshvar Ran, M Esfahani, M Payman, M Rabiei, H Samie Zadeh,
Volume 12, Issue 46 (1-2009)
Abstract
The effects of tillage methods and residual management on yield and yield components of rapeseed (Brassica napus L. CV. Hyola308) were evaluated after rice harvest. The experiment was carried out during 2004-2005 cropping season in a factorical arrangement of treatments at Rice Research Institute of Iran (RRII) in Rasht, in a Complete Randomized Block Design with three replications. Treatments included tillage in three methods: a) conventional tillage b) minimum tillage, and c) no tillage, and rice residue management in two manners: a) removing residues, and b) not removing residues. Plant traits such as grain yield, oil percentage and yield, plant density, plant height, the lowest pody branch height from soil surface, number of pods per plant, plant and weed dry weight, leaf area index (LAI) and crop growth rate (CGR) were measured. Results indicated that grain yield was affected by the tillage type. Also, the effect of tillage type on plant height, number of pods per plant, the lowest pody branch height from soil surface, and oil yield was significant. The effect of residual management and residual management interaction and tillage were significant on none of the traits except for weed dry weight. Economic analysis indicated that rapeseed planting in a field with rice residual and minimum tillage had a relative advantage of less production cost in spite of nearly 15 percent yield decrease compared to other methods.
