JWSS - Journal of Water and Soil Science

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Flax (Linum usitatissimum L.) is an oilseed and widely adapted crop. Oil of regular genotypes of flax is used in industry because of its unique fatty acid profile. New, mutant genotypes of flax have oils similar to sunflower oil which can be used as edible oil. This experiment was conducted to investigate the genetic variation of agronomic traits and productivity in different edible and industrial oil genotypes of flax in Isfahan. The genotypes were evaluated in augmented design.

Based on the results, the average numbers of seedling/m² in edible and industrial oil genotypes were 178 and 367 with variation coefficients of 70 and 10%, respectively. Maturity also showed variation and varied between 89 to 116 days in edible oil genotypes and between 89 to 128 days in industrial oil genotypes. Plant height varied between 57 to 86 and 49 to 73 cm in edible and industrial oil genotypes, respectively. Seed yield also had considerable variations and varied between 429 to 2651 and 779 to 2389 kg/ha with variation coefficients of 35 and 25 in edible and industrial oil genotypes, respectively. Seed yield per plant showed a high and positive correlation with basal branches (r=0.77**) and bolls per plant (r=0.93**), but high and negative correlation with stand (r=-0.66**). Regression analysis revealed that approximately 96% of the variation in seed yield per plant was attributed to variation in bolls per plant, seeds per boll and seed weight and they were determined as the major yield components, respectively. Bolls per plant was the most important yield component and contributed to 87% of the variation for seed yield per plant.

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Edible-oil flax (Linum usitatissimum L.) can be an alternate oil-seed crop in Isfahan region. Seeding date is very important in obtaining higher grain yields and a successful flax production. The present study was conducted at the research farm, Isfahan University of Technology in the year 2000 to determine the effect of seeding date and genotype on yield, yield components and maturity of edible-oil flax. In this study, a RCBD with three replications, in which the treatments were organized as a split-plot experiment, was used. Seeding dates (Oct. 17, Nov. 16, March 15, April 13, May 14, June 13, July 15) and genotypes (four breeding lines of edible-oil flax) were considered as the main and the subfactor, respectively. The number of capsules per plant, seeds per capsule, 100-seed weight and seed yield were highest for all genotypes in the first seeding date. Average seed yield in the first seeding date was almost twice, triple and eight times as much as the second, third and the last three seeding dates, respectively. In the second seeding date there was no emergence because of low temperature. The genotype and seeding date interaction on seed yield and maturity was significant. In general, delayed seeding was accompanied by reduction of emergence, number of days to maturity, yield and yield components in all genotypes, with the exception that the last seeding date led to increased number of days to maturity and seeds per capsule. Based on regression analysis, seed weight, number of seeds per capsule and number of seedlings/m2 were the most important components that contributed in seed yield variation, respectively. But, most of the variations in seed yield per plant was affected by number of copsules per plant and number of seeds per capsule, and in that order.

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Flax (Linum usitatissimum L.), an oilseed crop, is widely adapted and grown in many regions of the world. Oil from regular flaxseed is used as an industrial drying oil because of the high level of linolenic acid (>50 %). However, the oils from new mutant genotypes of flax with a very low linolenic acid concentration (<2 %) are edible. Yellow seed colour can be used as a visual marker to distinguish edible-oil genotypes of flax from those of industrial type that are usually brown-seeded. In this study, different lines of flax with two seed colours (yellow and brown) in combination with two levels of linolenic acid (high and low) were evaluated in a randomized complete block design for agronomic traits, especially seed yield and its components. The results indicated that lines with high linolenic acid concentration had significantly higher seed yield than those with low linolenic acid. However, other characteristics including those of seed yield components were not siginficantly affected by linolenic acid concentration. Seed colour had a significant effect on number of seedling/m², basal branches, capsules per plant and seed yield per plant. Although seedling emergence was lower in yellow-seeded lines, they had more basal branches, capsules per plant and seed yield per plant. Higher seed yield per plant in yellow-seeded lines can be attributed to higher number of capsules per plant as a result of lower seedling emergence and plant density. Seed yield was not significantly different between brown and yellow-seeded lines. Thus, the effect of lower plant density in yellow-seeded lines was compensated by their higher basal branches and number of capsules per plant.

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In order to investigate agronomic traits and yield potential of edible-oil flax (Linum usitatissimum L.) as a second crop in Isfahan region, different genotypes were evaluated in separate experiments in early spring (April, 7) and summer (July, 16) planting dates, using a Randomized Complete Block Design with three replications. The experiments were conducted in agricultural research farm, Isfahan University of Technology in the year 2000. The results showed that summer planting considerably and significantly reduced number of seedlings per unit area, days to 50% flowering, and seed yield. However, maturity of the plants was delayed because of summer planting. According to overall average obtained for genotypes, seed yield was 1472 and 213 kg/ha in the first and second planting dates, respectively. There was a significant difference between genotypes for number of seedlings per unit area, days to 50% flowering and maturity in both planting dates. However, genotypes were significantly different for seed yield in the first planting date. Summer planting also non-significantly reduced yield/plant, capsules/plant and 100-seed weight and increased seeds/capsule. The differences between genotypes for these traits in both planting dates and for seeds/capsule in the first planting date were significant. The significant interaction between genotypes and planting dates on seeds/capsule and 100-seed weight was because of increasing or decreasing levels of these traits in some genotypes when planting date was delayed. The results of regression analysis, correlation coefficients and path analysis showed that in both planting dates, capsules/plant followed by seeds/capsule and 100-seed weight were the major components of yield/plant. Capsules/plant had the most (approximately 80%) contribution in variation of yield/plant in both planting dates. The number of plants per unit area affected yield/plant via indirect and negative effect of capsules/plant.

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Safflower (Carthamus tinctorius L.) is one of the multi-purpose oilseed crops which has a high adaptation to different conditions such as resistance to drought and it is suited to be grown in arid and semi-arid regions such as Isfahan province. Root rot disease is an important soil-borne disease of safflower in Isfahan, which can be caused by different pathogens. The objective of this study was to determine the causal agent of safflower root rot and to evaluate different genotypes for tolerance to the disease. Different species of Fusarium were isolated from sample collections. Laboratory and greenhouse inoculations indicated that F. solani was the only pathogenic species. In this experiment, 60 genotypes of safflower including breeding lines selected from various Iranian local populations and foreign cultivars were evaluated for reaction to the disease in a randomized complete block design with three replications in greenhouse. Artificial inoculation via injection of spore suspension of F. solani (10⁶ spores/ml) was conducted on 8-week plants and then development of necrosis and death percentage were recorded. The results showed that there were significant differences among the genotypes in terms of reaction to the disease. The most resistant and susceptible genotypes were breeding lines of IUTE14310 and IUTC121 with mean necrosis of 9.67 and 28.33 mm, and death percentage of 32 and 74, respectively. Based on the means of necrosis and death percentage, the genotypes were significantly classified in 5 distinct groups including resistant (7 genotypes), moderately resistant (19 genotypes), tolerant (29 genotypes), moderately susceptible (3 genotypes), and susceptible (2 genotypes). The commercial foreign cultivars of AC Sunset, AC Sterling belonged to tolerant and moderately susceptible groups, respectively. However, Saffire was classified as a tolerant genotype. The local landrace of Kooseh which is widely grown in Isfahan province was classified as susceptible genotype. Phenotypic and genetic coefficients of variation (23.85 and 18.32 %, respectively) and a relatively high broad-sense heritability (59%) for necrosis and also the phenotypic and genetic coefficients of variation (25 and 21 %, respectively) and a high broad-sense heritability (73%) for death plants indicated that there was sufficient genetic variation for resistance and selection can be effective for producing resistant genotypes to Fusarium root rot disease.

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A diallel analysis of eight bread wheat (Ttriticum aestivum L.) cultivars was conducted to determine genetic parameters and the type of genetic control for yield and yield components. The parents and their F1 hybrids were evaluated in a randomized complete block design with 3 replications. General and specific combining ability effects were estimated by the method 2 of the Griffings model I, and the genetic parameters were estimated by the Jinks-Hayman method. According to the analysis of variance, the variances of parents and crosses were significant for all of the traits, except for the fertile tillers per plant in parents and harvest index in crosses. The variance of GCA was significant for almost all of the traits. GCA to SCA ratio indicated a large additive effects for all the traits, except for the number of fertile tillers, grain yield per plant and biological yield. Darab and Chamran cultivars were the excellent general combiners for days to heading. However, Falat for plant height, Arvand for number of fertile tillers, spike length and grain weight per spike, Qods and Arvand for spikeletes per spike, Falat and Arvand for grain yield per plant and Qods and Arvand cultivars for biological yield were the best general combiners. Based upon the Jinks-Hayman method, the average degree of dominance for grain weight per spike, 1000- grain weight, grain yield per plant and biological yield indicated that these traits might be controlled by over dominance effects and other traits by partial dominance. The correlation between Yr and (Wr + Vr) for the flag leaf length, spikeletes per spike, grains per spike and 1000-grain weight indicated that recessive allels enhanced these traits. But dominant allels had their contribution to enhance other traits. The narrow-sense heritability for grain yield per plant (4%) and biological yield (14%) and harvest index (37%) was lower. However, for other traits it was more than 50%. Therefore, it can be inferred that indirect selection of grain yield through selection for yield components such as spikeletes per spike, grains per spike and grain weight per spike with high heritability and correlation with grain yield can be more effective.

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To study the genetic variation of different traits, 66 isolated lines from different Iranian safflower landraces of Isfahan, Azarbaijan, Khorasan, Kordestan, Central provinces along with 13 foreign genotypes and two local populations of Kooseh and Arak-2811 were evaluated in a simple lattice design with two replications. The experiment was conducted at the research farm, Isfahan University of Technology in the year 2001. The results indicated that there was significant differences among the genotypes for all the traits including days to 50% flowering, maturity, plant height, yield/plant, seed yield and its components and relative resistance to the powdery mildew disease (p<0.01). Seed yield of genotypes varied from 1285 to 3524 Kg/ha. The seed yield of local population of Kooseh which was dominant growing cultivar in Isfahan province and one of the latest in maturity and tallest genotype was 2317 Kg/ha, however, some genotypes were earlier in maturity and had the less plant height and more seed yield than Kooseh. Seed oil content was measured for the 20 high yielding isolated lines by the Soxhlet method and varied from 24.62% (in one of the isolated lines from Kordestan landrace) to 37.55% (in one of the isolated lines from Kooseh). The genotype of Kooseh had seed oil content of 35.99%. Based on the results of cluster analysis, the genotypes were classified in to 3 the distinct clusters and they were significantly different for all of the traits, except for days to 50% emergence. One of the clusters had the maximum seed yield, seed yield/plant, branches/plant, capitula/plant, seeds/capitulum and the minimum of seed weight. It was implied that the genotypes of this cluster which were isolated from local populations could be used for improving the seed yield. The cluster analysis also indicated that in isolated lines from different provinces, there was no special pattern between the genetic and geographical diversity.

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Safflower (Carthamus tinctorius L.) is an oilseed crop and can have a considerable contribution to vegetable oil production in the country, since it has a high adaptability to different environmental conditions. This crop is grown in summer time as a second crop in Isfahan province. Therefore, this study was carried out to investigate the agronomic characteristics of the safflower breeding lines which were isolated from local populations of Iran in early spring and summer planting dates. Seven genotypes were evaluated at two planting dates, early spring (16 March) and summer (21 June), using a randomized complete block design (RCBD) with 4 replications at the research farm of Isfahan University of Technology. The results showed that the number of days to emergence, days to flowering and maturity and plant height decreased considerably in the summer planting date. However, the harvest index, seed yield per plant and seed yield per plot and oil yield increased in this planting date. Yield components were not significantly different in the two planting dates, except that 100-seed weight was significantly and considerably more in the second planting date. The average seed yield of genotypes was 2498 and 2845 kg/ha in spring and summer planting dates, respectively. In the first planting date, seed yield varied from 1876 Kg/ha, (for Kouseh genotype as check variety) to 2908 Kg/ha for E2428 line (selected from Isfshan population). In the second planting date, seed yield had a variation of 2124 to 3186 Kg/ha for the genotypes of S3110 (selected line from Khorasan population) and C111 (selected from Kouseh population), respectively. In the second planting date the check variety (Kouseh population) had a seed yield of 2965 Kg/ha. In both first and second planting dates, genotypes of E2428 and C116 (selected line from Kouseh population) had the maximum oil content in the seed, (33.9% and 32.3%د respectively). Genotype by planting date interaction was significant for seed yield and oil yield, since late planting date reduced seed yield in genotypes of S3110 and E2428, but it increased these traits in other genotypes.

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This experiment was conducted to evaluate drought tolerance of selected lines from local populations of safflower (Carthamus tinctorius L.) at the Research Farm of Isfahan University of Technology in 2002. In this study, the 12 selected safflower lines from different local populations along with two exotic cultivars and a local population were evaluated at two different irrigation regimes, using a randomized complete block design with three replications. The first and second irrigation regimes were based upon the depletion of 50% and 85% of soil moisture content, respectively. The results showed that there were significant differences (p<0.01) among the genotypes for seed yield in both irrigation regimes. Also, the interaction between genotypes and irrigation regimes was significant (p<0.05). Based upon the genotype by environmental interaction analysis (method of Sneller and Dombek), the genotype H27 had the highest tolerance to drought stress, and its seed yield in the first and second irrigation regimes was 3353 and 3072 kg/ha, respectively. The growing variety in Isfahan province (Koseh population) was the most sensitive genotype to the drought stress and had a seed yield of 3525 and 2394 kg/ha in the above irrigation regimes, respectively. The assessment of different water stress indices (SSI, STI, TOL, GMP and MP) revealed that STI seems to be the most suitable index for recognizing the more tolerant genotypes to drought conditions and based on this index, E2428 was the most tolerant genotype, and the exotic cultivar of Ac-Sunset (from Canada) was the most sensitive one. The seed yield for genotype E2428 was 4174 and 3458 kg/ha, and for the genotype Ac-Sunset was 2004 and 1438 kg/ha in the first and second irrigation regimes, respectively.

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The precision of evaluation for agronomic traits is very important in the field experiments to determine the genetic potential of genotypes or effect of treatments. The precision of the experiment mainly depends on the number of replications. The objective of this study was to investigate the effect of number of replications on the precision of genotype evaluation, estimation of variance components and on the heritability for agronomic traits in flax (Linum usitatissimum L.). In this study, nine genotypes of flax were evaluated for different traits, using a randomized complete block design with 8 replications. The results showed that the reduction of error variance due to increasing the number of replications mainly depended upon the type of the trait. For evaluation and estimation of heritability for number of seedlings /m² and plant height, 3 and 2 replications were suitable, respectively. The results also showed that using more than 2 replications had no considerable effect on the prescision of evaluation, nor on the increase of heritability for days to maturity. Based upon the results, for evaluation of the number of capsules per plant, 3 or 4, and for seeds per capsules, 4 replications can be suggested. For seed yield that is the most important economic trait in flax, a relatively constant estimated mean and broad-sense heritability were obtained with 4 to 8 replicationshowever, using 2 or 3 replications over-estimated the mean of the triat (approximately 11%) and under-estimated the broad-sense heritability about 27% and 10%, respectively. With 2 replications, the estimated mean and broad-sense heritability for seed yield were 2017.6 kg/ha and 72.1%, respectively. Gain from selection for seed yield based on evaluation of genotypes with 2, 3 and 8 replications was estimated as 787, 796 and 798 kg/ha, respectively. Therefore, it seems that 2 replications can also be used for seed yield evaluation of genotypes in breeding programs of flax.

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This study was carried out to evaluate the yield potential and other agronomic traits of nine genotypes of flax at two different spring planting dates: April 4 and May 5, 2003 and 2004, using a randomized complete block design with three replications at the Research Farm of Shahrekord University. The results showed that the effects of planting date and genotypes were significant on all of the traits, and the genotypes had a great genetic variation. On average, the range of number of seedlings/m2, maturity, plant height, yield/plant, seed yield and seed oil content of genotypes were 306 to 464, 93.3 to 105.1 days, 28.8 to 58.2cm, 0.274 to 0.569g, 995 to 1423 kg/ha and 32.88 to 34.83%, respectively. The lowest mean of plant height and the highest mean of seed yield/ha were observed for Kordestan local population. Late planting significantly decreased the number of seedlings/m2, days to maturity, plant height, yield/plant and seed yield/ha, while this increased seed oil content. Average of seed yield/plant and seed yield/ha in the first and second planting dates were, respectively 0.506 and 0.414g, and 1598 and 811 kg/ha. Significant interaction of genotype by planting date for seed yield/ha and seed oil content was mostly due to the variation in the reduction of seed yield and increasing or decreasing of seed oil content in some genotypes in the second planting date. The genotypes had a variation of 1358 to 1784 and 632 to 1088 kg/ha for seed yield in the first and second planting dates, respectively. The local population of Kordestan had the highest mean of seed yield in both years. The results of regression analysis and also the correlation coefficients showed that the number of seedlings/m2 and seed yield/plant had the most contribution to the seed yield variation. The trait of number of seeds/capsule and number of capsules/plant were the main and most important yield components affected on seed yield/plant and due to can be used as selection criteria in selection programs to improve seed yield.