Showing 45 results for Rezai
Abdolmajid Rezai,
Volume 1, Issue 1 (summer 1997)
Abstract
The relation between high molecular weight glutenin subunit alleles and flour quality traits have been studied for 117 recombinant inbred lines (RILs) derived by single seed descend to F7 from a cross of Anza, a low quality cultivar, and Inia, a high quality cultivar, containing different alleles at 3 GLU-1 seed storage protein loci. RILs were classified by SDS-PAGE for the 8 possible combinations of the alleles. The allelic variation at the GLU-D1 locus accounted for most of the variation observed in SDS-sedimentation, mixing time and tolerance, and protein content. The GLU-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+ 12. All three loci had significant single locus additive effects for SDS-sedimentation volume and mixing tolerance. The additive effects of GLU-D1 locus on mixing time and protein content were also significant. The epistatic additive effects were mostly negative and with the exception of αAB and αAD for SDS-sedimentation volume were not significant.
Majid Afyuni, Yahya Rezainejad, Babak Khayambashi,
Volume 2, Issue 1 (spring 1998)
Abstract
Land application of sewage sludge is potentially beneficial as an inexpensive nutrient source. However, problem with the use of sludge may exist from high soil concentrations and subsequent uptake of heavy metals by plant and entering of the metals into the human and animal food chains. A field study with lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.) was conducted to examine uptake of heavy metals from a sludge amended soil as affected by sludge rate and time of sludge application. Sludge rates were 0, 22.5, and 45 ton/ha. To determine the effect of time on heavy metal uptake, a year after the first plants were harvested, one third of each plot was planted without sludge application and to the rest of each plot sludge was added in the same rates as before. Total and EDTA-extractable Cu, Zn, Pb, and Cd concentrations in soil were determined. The metal concentrations in shoots and roots of the plants were determined separately. Total metal concentrations showed an increasing trend with addition of sewage sludge. Copper, Zn, and Pb EDTA-extractable concentrations in soil and concentrations of these metals in the plants increased significantly with sludge rate. Time of sludge application did not have any significant effect on EDTA-extractable and plant uptake of metals. Sewage sludge also increased the crop yields significantly.
Abdolamjid Rezai, Reza Amiri,
Volume 2, Issue 1 (spring 1998)
Abstract
Diallel crosses among 6 Avena sativa L. and A. sterilis L. lines and introductions were used to evaluate the validity of the assumptions for the genetic model. Number of days to pollination, plant height at pollination and at maturity, as well as grain and stem protein percentages were evaluated. According to Griffing's method 1 the reciprocal mean squares for all the traits under study were significant. But based on Hayman's analysis, the maternal effects for all the traits studied were not significant. Therefore, reciprocal means were used to evaluate the validity of the absence of multiple alleles, linkage and epistasis effects using regression of Wr on Vr and analysis of variance for Wr + Vr and Wr - Vr. Based on the results of the 3 methods, the genetic models for plant height at maturity and days to pollination were unbiased. Therefore, Hayman's analysis was used to estimate the genetic parameters for these traits. For plant height at pollination and stem protein percentage, significant and nonsignificant differences of regression slope from one and zero (Ho: β = 1 and Ho: β = 0) were detected, respectively. For these traits the biasedness of the model was removed after elimination of one parent from the diallel table. Grain protein percentage was not analyzed as it necessitated the elimination of 2 parents from the diallel table. In general, regression of Wr on Vr compare to Wr + Vr and Wr - Vr analysis of variances showed to be a more valid inductive method for testing the accuracy of the genetic model assumptions. Also, results of the Hayman and Jinks analysis, both when the assumptions are valid and when not, showed that genetic parameters are affected by the biasedness of the model, and that different estimates will be obtained. The Griffing's method was less affected by the unbiasedness of the model than Hayman and Jinks method. Therefore, it seems that preliminary testing for validity of the assumptions is necessary in Hayman and Jinks genetic model.
Farhad Ghavami, Abdolmajid Rezai, Siroos Abdemishani, Ahmad Arzani,
Volume 3, Issue 2 (summer 1999)
Abstract
Variability of seed storage protein electrophoretic patterns revealed by SDS-Polyacrylamide gel electrophoresis and their possible relations with some morphological and phenological characteristics were studied using 193 accessions from Iran Mungbean (Vigna radiata L. Wilczek) Collection. Seed protein electrophoresis revealed six different patterns that were different in two albumin and four globulin subunits with molecular weights of 23500-34000. Pattern types 1 and 2 had a considerable frequency but pattern types 3, 4, 5 and 6 had low frequencies and probably had developed recently in mungbean evolution process. Cluster analysis of countries and cities using the frequencies of albumin and globulin subunits showed no relation between geographical diversity and similarity distances. The correlations of morphological traits and albumin and globulin subunits indicated a relationship between G1 and G2 subunits with 1000 seed weight and days to beginning of maturity. Therefore, selection based on protein patterns at preliminary stages of breeding programs might be effective in increasing seed yield together with earliness.
R. Amiri, A. Rezai, M. Shahedi, S. Dokhani,
Volume 3, Issue 3 (fall 1999)
Abstract
This study was conducted to evaluate the capability of reversed-phase high performance liquid chromatography (RP-HPLC) of wheat (Triticum aestivum L.) storage proteins, and their genetic variability in different winter and spring isolines, cultivars and landraces. Gliadin proteins were extracted from the flour of five randomly selected seeds of each genotype. In this method, Nucleosil C18 300 A column (250×4.6 mm ID), equipped with a guard column and acetonitrile containing TFA as mobile phase was used.
All selected conditions for RP-HPLC such as suitable velocity and resolution were sufficient to achieve the objectives of this study. Under these conditions, the number of gliadin components by RP-HPLC analysis was more than electrophoresis subunits. In addition, quantitative results of RP-HPLC facilitated the data analysis. Also gliadin analysis by RP-HPLC had a high potential in detecting rye (Secale cereale L.) genes, so that the presence of ω-secalins in the genome of Falat variety was easily detected. Therefore, it was concluded that RP-HPLC analysis of gliadin proteins is as efficient as electrophoresis, and could even replace it in some cases. The result of cluster analysis for gliadin polypeptides indicated the gradual increase of genetic variation from isolines to landraces. Generally speaking, among the landraces, Ali Abad, Aghda, Sefid Bafghi, Ghermez Bafghi, Shahdas and Sorkheh had greater genetic variations.
B. Siahsar, A. Rezai,
Volume 3, Issue 3 (fall 1999)
Abstract
In order to study the genetic and environmental variability of morphological and phenological characteristics and also to gain a better understanding of the morphological basis of yield variation in soybean, an experiment was conducted at Research Farm, College of Agric., Isfahan University of Technology, in 1996. The experiment was arranged in three augmented designs with 285 lines and 5 control varieties. There were highly significant differences among genotypes for all the characteristics studied. The phenotypic coefficients of variability were greater than the genotypic ones for all the traits although the differences for most of them were small. The highest phenotypic and genotypic coefficients of variation, in order of magnitude, were obtained for number of pods per plant, days to flowering, plant height, height of the lowest pod, and number of lateral branches. Heritability estimates and the percent of genetic improvement for these traits and seed weight were high but for seed yield per plant were low. The lowest coefficients of variability were related to number of seeds per pod and days to germination. The results of stepwise regression analysis indicated that the maximum variation in seed yield could be attributed to the number of pods per plant, number of seeds per pod, and 100-seed weight. Factor analysis in addition to emphasizing the importance of yield components, resulted in four factors which determined 97.34% of yield variation. These factors which were indicators of physiological sink and source, with respect to the traits contained, were named as photosynthetic sink, plant architecture, fixed capital, and weight, respectively. In general, it was concluded that in order to improve soybean cultivars, selection should be in favor of plants with stronger structure, higher number of leaves, nods and pods per plant, and higher seed weights.
V. Rameeh, A. Rezai, A. Arzani,
Volume 4, Issue 2 (summer 2000)
Abstract
Diallel crosses of six breeding inbred lines of corn (Zea mays L.) were used to estimate combining abilities, heterosis and some other genetic parameters for yield and some of its components. Parents, 15 F1 crosses and 4 filler genotypes, were evaluated in a 5×5 simple lattice design. For all the traits studied, except seed length, the efficiency of lattice design was less than one. Therefore, data were analysed as a randomized complete block and after eliminating the filler genotypes, Grriffing’s method 2 with mixed B model was used in the genetic analyses.
General and specific combining ability (GCA and SCA) mean squares were statistically significant for all traits studied. The ratios of GCA to SCA mean squares were greater than one for all traits, except for the number of seed rows per ear, indicating the importance of non-additive gene effects in their genetic control. Low heritability estimates and degrees of dominance lower than one were further evidence of the presence of non additive gene effects for all the traits studied, except for the number of seed rows per ear. Therefore, production of single cross hybrids in order to take advantage of non-additive gene effects is of prime importance for grain yield, number of seeds per ear row, l00-seed weight, seed length, ear length, and comb percentage. For genetic improvement of number of seed rows per ear, selection methods for parental lines will be more efficient. In the hybrids studied, number of seed per ear row and l00-seed weight played a more important role in the observed variations in yield. In general, hybrids 4×5 and 5×6 with high SCA for number of seed per ear row, l00-seed weight and grain yield were considered favorable for the conditions of this study.
A. Soltani, A.m. Rezai, M.r. Khajeh Pour,
Volume 5, Issue 1 (spring 2001)
Abstract
Identification of easily measured physiological traits contributing to yield under specified environmental conditions would benefit genotypic selection for grain sorghum. A field experiment was conducted to determine broad-sense heritability and expected genetic advance, and to examine the relationships of grain yield with 11 physiological traits related to developmental periods, vegetative growth, growth rate, grain filling rate, and partitioning to the grain.
Sorghum genotypes exhibited significant differences for all traits, except for grain yield. Broad-sense heritability estimates ranged from a low of 49.6 (for grain filling rate per unit area) to a high of 99.4 (for days to maturity). Expected genetic advance ranged between 9.2% (for days to transition of vegetative to reproductive phase, days to maturity and number of leaves) and 39.8% (for grain filling rate per grain unit). Generally, grain yield gave a significant negative correlation with physiological traits related to development and vegetative growth. But, this correlation was positive and significant for growth rate, grain filling rate, and harvest index. Grain yield was low in its coefficient of genetic variation and expected genetic advance. It is, therefore, concluded that indirect selection for grain yield via growth rate, grain filling rate per unit area and harvest index is efficient. Results suggest that use of easily measured physiological traits in sorghum breeding is possible.
R. Amiri, A. Rezai,
Volume 5, Issue 2 (summer 2001)
Abstract
In order to evaluate the relationship between SDS-sedimentation value and breadmaking quality of wheat (Triticum aestivum L.), glutenin subunits of different genotypes (foreign and Iranian cultivars) were analyzed by reverse-phase high performance liquid chromatography (RP-HPLC). SDS-sedimentation value was used as an indirect criterion for breadmaking quality.
Correlation coefficients revealed a closer relationship between low molecular weight (LMW) glutenin subunits and variation in SDS-sedimentation value. Principal component analysis confirmed the presence of association between some of the glutenin subunits and SDS-sedimentation value. Based on the stepwise regression analysis, two LMW and four high molecular weight (HMW) peaks (subunits) were selected which accounted for 70.2 and 18.7% of variability in SDS sedimentation values, respectively. On the basis of the results of the stepwise regression analysis, a discriminant function was developed. The great efficiency of discriminant function in correct classification of completely different genotypes (Iranian landraces and cultivars) showed that the observed relationship between glutenin subunits and SDS-sedimentation value has a genetic basis and the effects of LMW and HMW glutenin subunits on SDS-sedimentation value are additive. Therefore, it seems that this method based on more protein components (rather than only on HMW glutenin subunits) can be used to predict breadmaking quality of wheat against many genetic backgrounds.
A. Dehdari, A. Rezai, M. Mobli,
Volume 5, Issue 2 (summer 2001)
Abstract
In order to evaluate the morphological and agronomic characteristics of 19 land races of onions and one foreign cultivar (Yellow Sweet Spanish), an experiment was conducted in 1998 at the Research Farm of the College of Agriculture, Isfahan University of Technology.
Analysis of variance showed significant differences among genotypes for all of the morphological and agronomic traits. Dry weight and number of days to emergence had the highest and lowest coefficients of genetic variability, respectively. Plant fresh weight, yield of 30 plants and total yield also had high coefficients of variability. Broad sense heritability estimates were high for all of the traits, indicating low environmental affects them. Based on cluster analysis and plot of the first two canonical variables, the genotypes were classified in four groups with different agronomic traits. Canonical discriminant analysis based on nine agronomic traits introduced three canonical variables which justified 99.9 percent of the total variation among characters. Principal component analysis revealed four components while factor analysis showed three factors which explained 87.3 and 95.5 percent of the total variation among characters, respectively. The first and second factors were related to adaptation and assimilate translocation, respectively. Bulb diameter, bulb height and bulb weight in positive directions and sensitivity to Fusarium in negative direction had greater loads in the third factor.
A. Rezaizad, B. Yazdi Samadi, M.r. Ahmadi, H. Zeinali,
Volume 5, Issue 3 (fall 2001)
Abstract
To determine the relationships between yield and its components, and to find the direct and indirect effects of yield-related traits on soybean yield, 240 genotypes were grown in the Research Station, College of Agriculture, Karaj, Iran, in 1997-98 using an augmented design. The study of correlation analysis showed that number of seeds per plant and seed yield per plant had the highest significant correlation coefficient (r=0.92). Other significant correlation coefficients were found between biomass per plant and yield (r=0.86) and between number of pods per plant and yield (r=0.67). Results of stepwise regression analysis revealed that number of seeds per plant, seed weight, and number of seeds per pod were the three major traits affecting seed yield in soybean. However, path analysis showed that only two of the three above-mentioned traits, namely, number of seeds per plant and seed weight, are quite important for soybean selection programs. Stepwise regression analysis was used again, omitting number of seeds per plant, which showed that number of pods per plant, seed weight, plant height and number of days to 90% maturity, are important contributors to yield. Path analysis, this time, revealed that the correlation effects to plant height and number of days to 90% maturity on yield is due to the indirect effects exerted through other traits. It is concluded that three traits, namely, number of seeds per plant, seed weight and number of pods per plant have notable effects on soybean seed yield.
F. Azizi, A. Rezai, S.m. Maybodi,
Volume 5, Issue 3 (fall 2001)
Abstract
In order to investigate the genetic diversity of morphological traits in 121 genotypes of lima, red and pinto beans, and to study the relation between characters, and to get better understanding of factors affecting the interaction between characters by multivariate analysis, an experiment was conducted in 1997 as a simple lattice design at the Research Station of Agricultural College, Isfahan University of Technology.
High variability was observed among genotypes for all characters studied. The phenotypic coefficients of variability were greater than the genotypic ones for all the traits. Among the characters studied seed yield, number of pods per lateral branches and main stem, length of lateral branches and main stem, number of nodes per lateral branches and main stem, 100-seed weight and number of lateral branches had the highest genotypic and phenotypic variability, while days to maturity had the lowest variability. Traits relative to lateral branches were more variable than the same traits in the main stem. Factor analysis for all the genotypes and, separately, for lima, red, pinto, determinate and indeterminate genotypes revealed 4 factors which justified more than 78.4 percent of the total variation. The results of the analysis based on all the genotypes showed that the first factor was mostly correlated to days to maturity, length of main stem and lateral branches, number of nodes per main stem and lateral branches, which was named “vegetative factor”. The second and third factors had the highest correlations with number of pods per main stem and lateral branches, number of seeds per pod in the main stem and branches and 100-seed weight, which were named “yield component factors”. The fourth factor showed the highest correlation with number of lateral branches and was named for this trait. The first and fourth factors were related to vegetative growth characteristics and physiological source. The second and third factors were related to physiological sink. On the basis of stepwise regression analysis, number of pods per lateral branches was the most important component of yield, and number of pods per lateral branches and main stem had the next following ranks. Number of pods per lateral branches and main stem had the highest relationships with yield.
A. Dehdari, M. Mobli, A. Rezai,
Volume 5, Issue 4 (winter 2002)
Abstract
In order to determine the relationships among the different traits of onion and to study the direct and indirect effects of these traits on bulb and seed yield, an experiment was conducted in 1998 at the research farm of Isfahan University of Technology. Results showed that phenotypic and genotypic correlations were similar and bulb weight showed the highest and lowest coefficients of correlation with bulb diameter and number of days to emergence, respectively. Results of stepwise regression analysis showed that leaf width at 25% of its length from the neck, leaf length, and leaf dry weight were the best estimators for leaf area bulb diameter, bulb length, plant height and number of days to maturity were the most important determining characters for bulb yield variation. Number of fertilized florets was the best determinator of seed yield and bulb weight, while diameter and volume were the best describing characters for the number of meristems on the basal plate. Path-coefficient analysis revealed that bulb diameter showed the highest direct positive effect on bulb yield and the indirect effect of plant height through bulb diameter on it was of prime importance. Number of fertilized florets per plant and number of inflorescence per plant through the number of fertilized florets showed the highest direct and indirect effects on seed weight, respectively.
H. Alipour, A. Rezai, S. A. M. Meibodi, M. Taheri,
Volume 5, Issue 4 (winter 2002)
Abstract
This experiment was conducted to study genetic variation for electrophoretic seed protein patterns and their relations with some seed characteristics such as protein and oil percentages, chemical compositions and 100-seed weight among 270 soybean (Glycine max L. Moench) genotypes.
Among different electrophoresis procedures examined, 10% and 4.5% concentrations of acrylamide for resolving and stacking gels, respectively, 13.5 mg/ml concentration of protein buffer extraction, injection of 10 microlitre sample injection into gel hollows, 2.5 miliamper and 2-hours staining period were determined as the best combination to achieve clear bands and good separation. Based on relative mobility on gel, 30 protein bands were observed, of which only 5 varied among genotypes. In general, 8 electrophoretic patterns were recognized. Cluster analysis based on qualitative evaluation of patterns grouped the genotypes in 8 clusters and classified different bands in three groups. Simple concordance (matching) coefficients between protein bands with relative mobilities of 2.5% and 49.5% were zero, which is an indication of their independent occurrence. Probably, these bands are coded with one gene that in dominant and recessive homozygous genotypes appear as a single band at different positions on the gel. Analysis of variance revealed significant differences (P<0.05) among protein patterns for protein and oil percentages. Correlation coefficients between variable protein bands and studied traits showed a positive and significant relation (P<0.05) of bands with relative mobility of 3.5 and 49.5 with protein and phosphorous contents of the seeds, respectively. Protein patterns having band with relative mobility of 49.5 had the highest phosphorous content. Black hilum color of seeds was related to protein band with relative mobility of 52.
F. Shahin Nia, A. Rezai, A. Saedi,
Volume 6, Issue 2 (summer 2002)
Abstract
The variation and path coefficient analysis of bread-making quality traits have been studied for 145 genotypes of breeding lines, cultivars and landrace varieties of wheat (Triticum aestivum L.). Bread-making quality traits of genotypes was evaluated indirectly by protein percentage, SDS and Zeleny sedimentation tests, hardness index, test weight, bread volume, grain moisture, and water absorption percentage. Hardness index, Zeleny and SDS sedimentation tests had the highest coefficient of variability (13.51%, 11.83% and 11.03%, respectively). Factor analysis for the genotypes, based on qualitative traits revealed two factors, which explain 98.23% of total variation and were named grain protein index and bread volume factors. The result of correlation analysis indicated positive and significant relationship between protein percentage, SDS sedimentation test and other bread-making quality traits. On the first and second steps of stepwise regression analysis, protein percentage was the most effective trait in explaining different qualitative trait variations. Path analysis also showed the direct and significant effects of protein percentage, Zeleny sedimentation volume, grain moisture and water absorption percentage, and bread volume on SDS sedimentation test. According to cluster analysis based on qualitative traits, the cultivars and landrace varieties, from the view poit of protein quality and quantity, had the highest potential among other groups (generally breading lines).
H. Seyedoleslami, A. R. Hadian, A. Rezai,
Volume 6, Issue 3 (fall 2002)
Abstract
Color sticky board traps are used in pest management for capture of adult insect, to estimate and predict population densities in later stages. Yellow sticky board traps showed high attraction for pistachio psylla. It is important to study these relationships for the right placement of traps. For each of three repetition in one year, four pistachio trees were selected randomly in one orchard. Eight traps were located on two heights and four cardinal directions of each tree (32 traps in each repetition). After one week the adult psylla captured were counted. One and two weeks 1ater, eggs and nymph densities were counted on five leaves in one of the eight positions of each tree on four other randomly selected trees (total 160 leaves each time). Data were subjected to analysis of variance. Coefficient of variation was determined between adults captured in each position and eggs and nymph density counts.
There were significant differences for adult capture and egg density among directions, and in most cases significant correlations were observed between adults captured on each position and total egg and nymph density count on trees. It was concluded that for egg and nymphal density estimation, we can place traps on either of two heights and four directions except on lower east part, but preferably on either height in south direction of the trees . Also suggestions for egg and nymph sampling are given in the text.
H. Seyedoleslami, A. R. Hadian, A. Rezai,
Volume 7, Issue 1 (spring 2003)
Abstract
High attraction is reported for yellow sticky traps to capture pistachio psylla. In pest management, it is important to forecast from the adult population density the density of other developmental stages in order to gain an estimate of the density in damaging stages. In 1998 and 1999, yellow sticky boards with 10150.15 cm were installed in two pistachio orchards in Borkhar district of Isfahan and egg and nymphal densities were simultaneously counted on leaves. Collected data were used to determine regression relationships between two weeks’ average egg density, first and second nymphal instar densities and the sum of egg and first and second instar nymphal densities, one week after the average adult capture in two previous weeks. A low correlation was found between egg count and adult capture, but higher coefficients were obtained between other stages. It was possible to estimate first and second instar nymphal populations from the following equations:
For high adult densities (X):
Y= 58.6+0.4762X-(7*10-5)X2 R2=0.82 commercial orchard
Y= 27.68+0.5092X-(5*10-5)X2 R2=0.86 abandoned orchard
and for low adult densities (X)
Y= 1.7162X-17.454 R2=0.97 commercial orchard
Y= 1.1117X-4.9841 R2=0.90 abandoned orchard
The application of this method is recommended for the management of pistachio psylla.
K. Zaynali Nejad, A. F. Mirlohi, G. Nemat Zadeh, A. Rezai,
Volume 7, Issue 4 (winter 2004)
Abstract
To study the genetic diversity in 100 genotypes of rice, an experiment was conducted at the research farm of Rice Research Institute of Iran. The experimental design was a 10x10 simple lattice. The genotypes, mostly belonging to Isfahan Province and north of Iran, were evaluated on the basis of morphological traits and yield components. The results of analysis of variance demonstrated that the differences among genotypes were highly significant (p < 0/01) for all traits. High values of phenotypic and genotypic coefficients of variation were obtained for most traits, indicating high variability in the traits under study. Factor analysis revealed three factors which determined 90 percent of yeild variation and were named “grain number”, “plant type and structure” and “grain shape”, respectively. Cluster analysis by “Cubic Clustering Criterion” and “Pseudo Hotelling T2 Test” grouped genotypes in four clusters. Analysis of variance showed that the differences among clusters were highly significant for most traits.
H. Rezaie, M.r. Neishabouri, A. R. Sepaskhah,
Volume 8, Issue 3 (fall 2004)
Abstract
Hydraulic coefficients of a porous media such as hydraulic conductivity K(θ) and diffusivity D(θ) have a controlling role in the evaluation of groundwater flow and pollutant transport behavior. Therefore, successful porous media flow evaluation depends on the accurate determination of its hydraulic coefficients. But it is hard and time consuming to measure. Values for these coefficients accurately as measurements usually task place at a moisture range close to saturation. This situation justifies the preference for prediction models to be used. One method for evaluation of K(θ) and D(θ) coefficients is to use models which take measured soil moisture characteristic curve data into consideration. For the purposes of the present study, pressure plates apparatus measured the required data to develop soil moisture characteristic curve for nine various soil textures. The volume of instantaneous outgoing water was measured with respect to time and the total volume of water released at the end of each experiment was measured for a given pressure (0.1 to 1.5 Mpa) imposed on undisturbed soil samples. A simple equation based on Richard’s equation is provided for the estimation of K(θ) and D(θ). Application of Mualem, van Genuchten et. al, Burdine, Green and Corey, and Gardner models for estimation of the K(θ) and D(θ) values at a variety of nine varied soil textures under experiment showed a wide range of variation. Therefore, it is hard to simulate the accurate hydraulic conductivity behavior for the given varied soil textures by means of the models available. However, if the minimum and maximum simulated values obtained from the models at respective soil moisture contents are considered to be a permitted range, one may state that the results of the estimated hydraulic coefficients by the proposed method in this study lie within the permitted range or agree with the results of other models considered. Therefore, the proposed method for determination of K(θ) and D(θ) is capable of selecting the best simulation model to estimate hydraulic coefficient values.
H. Sabori, A. Rezai, S. A. M. Mirmohammady Maibody, M. Esfahani,
Volume 9, Issue 1 (spring 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.
