JWSS - Journal of Water and Soil Science

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Immature embryo culture response of 28 durum wheat (Triticum turgidum var. durum) cultivars was studied using MS medium in Tissue Culture Laboratory of College of Agriculture, Isfahan University of Technology. Donor plants were grown in a recirculating hydroponic system and pots in a greenhouse. Regenerated immature embryos were recorded at 2, 4, 8 and 16 days after inoculation. Assessment of durum wheat cultivars for immature embryo culture was conducted by percentage and rate of regenerated embryo, using a split plot design arranged in completely randomized design with 5 replications. The analysis of variances showed that there were highly significant differences among cultivars for plant regeneration capacity. The highest potential and rate of embryo regeneration (two days after inoculation) were observed in “Shahivandi” which is a native cultivar of west Iran. “Awl1/Sbl4” with a mean of 48.5%, “Hagla” and “Ofen/Kil” with a mean of 80% have the poorest and the best mean of regeneration during the recording period, respectively. The high regeneration potential is important in view of reducing the time constrain and somaclonal variation in a breeding program.

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In vitro salt tolerance of 28 cultivars of durum wheat with native and exotic origins was investigated, using MS medium containing sodium chloride. The resulting calli were subjected to 8 salinity levels including 0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 percent NaCl (w/v). Donor plants of explant (immature embryo) were grown in a recirculating hydroponics and pots in a greenhouse as well as in the field. Assessment of calli was conducted after 0, 8 and 16 days after subculture of calli into the NaCl-contained medium. Callus growth rate, relative callus growth rate and percentages of callus necrosis were measured, using a 8 × 28 factorial experiment layout in a completely randomized design with 3 observations per treatment and 3 replications. Results of analysis of variances showed that among the criteria, relative growth rate of callus was the most reliable, while callus growth rate as not being quantitatively measured, was less devoted. Results of this study revealed that 'PI 40100' and 'Dipper-6' were superior genotypes for in vitro salt tolerance. The high relative callus growth rate and less callus necrosis of these cvs. may indicate their superior genetic potential for in vitro salinity tolerance.

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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.

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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.

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Knowledge of the effects of row spacings and seeding rates on dual-purpose forage and seed production of an annual legume crop is essential for its proper agronomical exploitation. In this study, the effects of various row spacings and seeding rates on dry matter and seed yield in berseem clover (Trifolium alexandrinum L.) were evaluated in two consecutive years. The experimental design was a split-plot with four row spacings as main plot treatments in a randomized complete block design with four replications, and five seeding rates were allocated to subplots.

Combined analysis of variance of the two-year data showed that both row spacings and seeding rates influenced dry matter yield (DM), seed yield, plant height, 1000-seed weight and harvest index. Years, as well as two- and three-factor interactions did not affect the seed yield whereas row spacing × seeding rate, and year × seeding rate significantly affected the DM. The mean comparisons indicated that row spacings of 30 and 45 cm produced the highest DM of 3912.2 and 3900 kg/ha 45 and 60 cm spacings showed the highest seed yield of 1045.4 and 1093.3 kg/ha, respectively. 24 and 20 kg/ha seeding rates ranked the best in giving 1244.7 and 1223 kg/ha seed yield, respectively. The seeding rate of 16 kg/ha in the first year and 20 kg/ha in the second year produced the highest DM yield with means of 3837.5 and 3875.3 kg/ha, respectively. Regarding the dual-purpose of forage and seed production in berseem clover, 20 kg/ha seeding rate at 45 cm row spacing can be recommended for Isfahan region and for other comparable environmental conditions.

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This study was conducted to evaluate the responses of Iranian commercial genotypes of maize (hybrids and their inbred lines) to callus induction and plant regeneration, using mature embryos. Twenty five genotypes comprising of 12 inbred lines, 11 single cross hybrids, 1 double cross hybrid and 1 composite cultivar were used. Mature embryos of the genotypes were plated on MS and N6 media. Callus induction rates were evaluated using relative growth rate of callus (RGR), callus fresh weight (CFW), callus dry weight (CDW) and callus growth rate (CGR).

The results indicated that genotypes highly varied in both callus induction and plant regeneration. IL8 inbred line, SC7 (IL4×IL8) and SC9 (IL6×IL10) hybrids had the highest callus production capacity (based on CFW and CDW), whereas the highest RGR and CGR were obtained for ILl inbred line and SC9 hybrid. The estimated heterosis based on superior parent showed the highest heterosis for CFW, CDW, RGR and CGR in SC9 hybrid. Genotype × medium interactions for CWD, RGR and CGR were significant. For instance, SC9 hybrid on MS medium and IL8 on N6 medium produced the highest CGR. There was a significant difference between the observation periods [8, 12, 16 and 20 days after planting (DAP)], so that CGR was the least at 8 DAP and increased gradually till 16 DAP, but declined afterward. CGR had a range of 0.51 in IL8 inbred line to 0.74 in SC9 hybrid. Comparisons of the genotype for plant regeneration percent indicated that ILl and IL10 inbred lines as well as SC2 and SC4 single cross hybrids had the highest regeneration rates. Considering plant regeneration as a critical and genotypic dependent factor, it can be concluded that ILl and IL10 inbred as well as SC4 (IL4×IL5, ‘single cross 301’), SC2 (IL2×IL3, ‘single cross 704’) and SC7 hybrids are recommended for use in tissue culture-based breeding programs in maize.

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This study was conducted to evaluate the response of 18 rice (Oryza sativa L.) genotypes to callus induction and plant regeneration from immature embryo culture, using three media (MS, LS and N6). To evaluate callus induction rate, the following criteria were used: callus diameter, callus fresh weight and callus dry weight. Percentage of callus water content was also measured. After transferring the produced calli from the induction media to a regeneration medium (MSR), percentage of plant regeneration was evaluated.

A highly significant difference was observed among genotypes for both callus induction and plant regeneration (P<0.01). In callus induction phase, “Nemat” and “Cheram-2” cultivars were superior for callus diameter, having 4.83 and 4.6 mm callus diameter, respectively. “Nemat”, “Cheram-2”, “Sepidrood” and “Taroum” cultivars as well as “33IRCTN91” and “IRFAON-30” lines were significantly superior to other cultivars for callus fresh weight. Among the genotypes “Nemat”, “Zayandehrood”, “33IRCTN91” had the highest percentage of callus water contents. Based on plant regeneration, “33IRCTN91” line and “Anbarbo”, “Nemat”, “Cheram-2” and “Taroum” cultivars showed highest rate of plant regeneration from callus. Significant differences were observed among media. While MS and N6 media did not showed any significant differences for callus diameter, callus fresh weight and rate of plant regeneration, they were superior to LS medium (P<0.01). According to percentage of callus water content, MS and LS media ranked the best and the most inferior medium, respectively. In the present study, MS and N6 media were considered as suitable in vitro culture media of rice immature embryos. Among genotypes, “Nemat” and “Cheram-2” cultivars were ranked the best for both callus induction and plant regeneration. Also, the used Japonica rice cultivars were superior for percentage of plant regeneration. The calculated correlation coefficients between traits showed a non-significant correlation between callus induction and plant regeneration, which, in turn, indicated that these traits were independent.

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To study grain quality traits and their relationships with high molecular weight (HMW) and low moleculor weight (LMW) glutenin subunits, 104 durum wheat genotypes were used. Six grain quality characteristics comprising wet and dry gluten content, test weight, grain hardiness, protein content and SDS sedimentation volume were studied. HMW and LMW glutenin subunits were evaluated using SDS-polyacrylamid gel electrophoresis (SDS-PAGE) in 33 genotypes. Statistical analysis including correlation coefficients, factor analysis, cluster analysis of genotypes based on qualitative traits, analysis of variance in qualitative traits based on HMW, LMW, and combination of subunits as well as all of subunits, and canonical correlation analysis between glutenin subunits and qualitative traits were used. Factor analysis of the genotypes detected 2 factors, which explained 65 percent of the total variation among the data. These were named quantitative protein and qualitative protein. Based on cluster analysis, the genotypes were classified into four clusters. The genotypes in groups 2 and 4 were beneficial in terms of protein quantity and quality. In evaluating glutenin subunits, 7 HMW subunits and 2 LMW subunits were detected. Subunit null of Glu-Al was observed. Subunits 7+8, 6+8, 13+16 and 20 at Glu-Bl were observed however, neither of them had significant differences in qualitative traits, but 6+8 and 7+8 had a higher SDS sedimentation rate than 20. LMW-1 and LMW-2 had significant differences in protein content and SDS sedimentation LMW-1 had higher protein content whereas LMW-2 had higher SDS sedimentation. Combibation of subunit LMW-1 / HMW 7+8 had the highest protein content and LMW-2/HMW 7+8 had the highest SDS sedimentation. Results of canonical correlation showed that presence of LMW-2 and HMW 7+8, and absence of LMW-1 and HMW 20 in durum wheats caused an increase in SDS sedimentation and a reduction in protein and gluten content.

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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.

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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.

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To determine the effects of salinity and boron excess in irrigation water on relative growth rate (RGR), net assimilation rate on a leaf weight basis (NAR), and leaf weight ratio (LWR) of pistachio, three pistachio rootstocks (Badami -Zarand, Sarakhs and Ghazvini) were used. Rootstocks were grown in soil in eight-liter polyethylene pots. Sodium chloride treatments were 0, 75,150 and 225 mM NaCl and boron treatments were 0, 20 and 40mg liter^-1. Treatments were applied to the one-year old pistachio rootstock seedlings in three-day intervals with irrigation water. Some plants were randomly selected and destructively harvested before (day 0) and after applying treatments (30 and 60 days after treatments started). Growth and physiological characters were then measured as follows: number of leaves, leaf area, plant height and root length, fresh and dry weights of stem, root and leaf, proline accumulation in the leaf, total chlorophyll, and leaf relative water content (RWC). Results indicated that relative growth rate decreased with time for all treatments and in all rootstocks. Salt treatment significantly reduced both RGR and NAR, whereas LWR showed no significant differences. In all rootstocks, NAR, but not LWR, was significantly correlated with RGR, indicating that NAR was an important factor underlying the salinity-induced differences in RGR among the pistachio rootstocks. Salinity did not affect leaf water potential (ψ), chlorophyll content, and Fv:Fm ratio but increased NaCl concentration and time correspondingly increased proline accumulation in leaves. In addition, Ghazvini rootstock accumulated more proline compared to other rootstocks and was more resistant to salinity treatments. Different boron treatments did not show any significant effect on growth rate nor on measured parameters after two months of exposure to treatments.

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This study was conducted to analyze the correlation among grain yield, yield components, duration of vegetative and grain filling periods in twelve oat (Avena sativa L.) cultivars at the Research Farm of the College of Agriculture, Isfahan University of Technology, from 2001 to 2003. A randomized complete block design with three replications was used. The correlation coefficients among the grain yield/m², fertile tiller/m², grain number/panicle and the duration of grain filling period were positive and significant. Among yield components, the number of panicle/m² and the number of grain/panicle had the largest direct effects on grain yield (0.68 and 0.30, respectively). Furthermore, the duration of the grain filling period had the highest direct effect on the number of grain/panicle and the grain weight (0.82 and 0.80, respectively), which were greater than its correlations with the number of grain per panicle (0.42) and 1000-grain weight (0.35). However, its negative indirect effects through other traits reduced the correlation coefficients. The results of path analysis indicated that the number of panicle/m² and the number of grain/panicle had the largest direct effects on the grain yield. Considering the direct effects of grain filling duration on the number of grain/panicle and the 1000-grain weight, and also the fact that most of the dry matter in oat is produced in this period, it seems plausible to use these traits as a selection criterion in breeding programs for higher yields of cultivars of oat.

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To evaluate heritability, phenotypic and genotypic correlation coefficients, phenotypic and genotypic variances as well as relationships between some of the grain quality traits, an investigation was conducted in a randomized complete block design replicated three times in 2001, using four durum wheat genotypes PI40100, Dipper-6, Oste/Gata, Shova and their F₂ and F₃ progenies derived from their crosses. Grain quality characteristics including seed hardiness, protein content, SDS sedimentation volume and gluten content were evaluated. The results indicated that wet gluten content and dry gluten content had the highest coefficient of variation. Statistical analysis showed a significant difference between genotypes for all traits with the exception of SDS sedimentation volume. Dry gluten content had the highest heritability (90.4%) while SDS sedimentation volume had the lowest heritability (48.6%). Results of correlation analysis indicated that seed hardiness correlated significantly with protein content, SDS sedimentation and dry gluten content. Protein content had a positive correlation with wet and dry gluten content. Since dry gluten content showed a high correlation with protein content (quantity) and seed hardiness had a high correlation with SDS sedimentation volume, hence these two traits can be used as the selection criteria for improving quality of protein in durum wheat.

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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/DH^1/2 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.

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Range suitability and its grazing capability are the most important criteria in rangeland analysis and monitoring. Determination and monitoring of factors affecting on range suitability and diagnosis of them are important .All range ecosystem components affect range suitability. Which among them physical and vegetational factors, forage production, water resources and sensitivity to erosion were considered. The objective of this research was to determine range suitability of Lar, Dasht bakan, Ardestan, Siahrood rangelands to design a model for sheep grazing. This study was carried out in four regions, two of them (Siahrood and Lar) located in Alborz mountain chain, Ardestan in center of Iran and Dashtbakan in Zagros mountain chain. According to the results among physical factors, slope remoteness of watering points and sensitivity to erosion had more effect on grazing capability than vegetation factors. In Siahrood watershed aboundancy of poisonous plants, high slope, transient watering points and non resistant formations were limiting factors. High slope, sensitivity of soils and stones to erosion, kind of exploitation in Lar watershed affected range suitability. In Ardestan watershed, low range productivity, presence of invader plants, erosion, remoteness of watering points are major limitation of range suitability. In Dasht Bakan factors including slope, elevation, dispersion of water resources and transient water resources were limited grazing capability. In land evaluation each land utilization type has certain land use requirement and each land unit has certain land qualities. Utilization of rangeland based on grazing capacity, range readiness and recreation of degraded rangeland can improve suitability of rangelands in the studied areas.

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An experiment was conducted to investigate the genetic diversity in the cultivars and F1 hybrids of durum wheat, using agronomic and morphological traits. Evaluation of consistency between choosing parents of crosses based on morphological and agronomic observations and genetic distance obtained from cluster analysis were objectives of this study. Fourty- two genotypes were evaluated using a randomized complete block design with three replications in 2003. Agronomic characteristics comprised days to 50% flowering, days to 50% pollination, days to maturity, plant height (cm), spike length (cm), grain weight per spike (gr), number of grain per spike, number of spike per m², grain yield (t/ha), biological yield (t/ha), 1000 grain weight, test weight (gr/L) and harvest index were measured in the studied genotypes. The results of analysis of variance showed significant differences among genotypes for all the studied traits. The results also revealed that grain yield had the highest coefficient of variation (CV= 21.6%), followed by spikes per m² (CV= 20%) and number of grains per spike (CV= 18.9%). Lowest coefficient of variation was observed in days to maturity, days to 50% pollination and days to 50% flowering. Moreover, correlation analysis indicated that grain yield correlated with harvest index, biological yield, grain per spike and grain weight per spike. Cluster analysis of genotypes based on agronomic traits defined desirable clusters. These clusters have desirable characteristics and are beneficial for breeding objectives. Results of evaluation of consistency between choosing parents based on observation and those of cluster analysis showed varing degrees of consistency in 12 conducted crosses, ranging from highly similar parents in Eupoda6×Chahba88 to relatively distinct parents in PI40100×PI40099 cross.

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  Sugarcane is one of the most important sugar crops in the world. Because of semi-arid climate and salinity of its cultivation area in our country, increasing salt tolerance of sugarcane is signifying. To achieve this goal determining salt tolerant cultivars and understanding salinity mechanisms in sugarcane are very important. This study was conducted to evaluate 8 commercial and promising sugarcane cultivars at early stage of growth. A complete randomized design with three replicates and four salinity treatments (0, 0.25, 0.5, 0.75 % NaCl) was used in a hydroponics system. The effect of salinity on absorption, transport and accumulation of Na⁺, Cl^- , K⁺ and Ca²⁺ ions in shoot and root was determined. At high level salt concentration, Cl^- content in shoot and root increased. Result showed that sodium accumulation in sugarcane plants was more than potassium. By increasing salinity level, sodium uptake and its translocation to shoots increased reducing growth and dry matter yield of plants. With rising salt concentration from medium (0.5%) to high (0.75%), content of chloride in shoot and root of NCO-310 was constant showed that this cultivar had genetic ability to avoid Cl^- uptake. CP82-1592 with lowest ratio of shoot / root chloride had minimum transport of Cl^- to shoots. Also this cultivar had high content of Ca²⁺ in shoot and low Na⁺/Ca²⁺ ratio at all salinity levels. CP48-103 had low sodium in shoot and relatively low sodium in root. Thus it probably has genetic potential to avoid sodium uptake. At last, exclusion of Na⁺ and Cl^- to older leaves and tillers was seen in CP82-1592 and CP72-2086 cultivars. According to results, to avoid once of absorption and transport, and exclusion of harmful Na⁺ and Cl^- ions were mechanisms that could be used in salinity tolerance of sugarcane.

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  Evaluation of genetic improvement of grain yield and other traits in cultivars released in different years is useful to determine plant breeding impact on grain yield improvement, to define future selection criteria and to identify the desirable environment and traits for further assessment. This study was conducted to evaluate the genetic improvement for grain yield and other traits of twelve oat (Avena sativa L.) cultivars released in Canada during 1921- 1997, at Research Farm, College of Agriculture, Isfahan University of Technology, during 2001-3 in a randomized complete block design with three replications. The regression of mean grain yield on released year of the cultivars showed that the rate of increase in grain yield during a 76-year period is 32.63 kg h^-1 year^-1 or 0.63% per year. Breeding programmes have inereased harvest index, grain number per panicle and fertile tillers /m². The effort of breeders in this period was to decrease plant height and days to heading. The other traits had small changes and showed no specific trends. In general the results of this study showed continous improvement of grain yield in this period. Genetic improvement of grain yield in evaluated cultivars closely correlated with harvest index. Therefore, most variation in grain yield of oats was due to variation in harvest index. Although much of the improvement in grain yield described here could be attributed to the increased harvest index, the scope for further improvement in this character may be limited. Further yield improvement of oats might be achieved by combining high biological yield with high harvest index.

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  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 H_{PI40100×PI40099} and H_{Eupoda6× Chahba88} hybrids. Furthermore, superior hybrids included H_{Altar84/Ald×Chahba88}, H_{Buchen7×Chahba88 and} H_{Eupoda6×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.

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  The most desirable approach to improve characteristics such as yield with polygenic inheritance and genotype × environment interaction, is simultaneous selection using selection index based on related traits. This study was conducted Research Farm of Isfahan University of Technology, to compare selection indices for barley yield improvement under nitrogen stress and non stress conditions, using 49 F₁₃ recombinant inbred lines derived from a cross between Azumamugi and Kanto Nakate Gold. A split plot design with randomized complete block layout in three replications was used. In non-stress condition 100 kg nitrogen per hectare as urea was used at early reproductive growth, stem elongation and grain filling stages. In stress condition, 50 kg nitrogen per hectare was only used at early vegetative growth stage. Smith-Hazel and Pesek-Baker indices based on 4 traits (days to heading, harvest index, growth rate and nitrogen harvest index) and also direct and correlated response of these traits were calculated. The result of response to selection and correlated response indicated that the selection based on higher harvest index and nitrogen harvest index under both conditions screens high yielding lines. Harvest index had high weight in both indices under stress and non stress conditions. Under both conditions and for Smith-Hazel and Pesek-Baker indices, growth rate had negative correlation coefficients. Therefore, the selection based on these indices, separates lines with lower growth rate. In this study, Smith-Hazel index had higher efficiency.