جستجوی مقالات مرتبط با کلیدواژه « heritability » در نشریات گروه « بیوتکنولوژی و ژنتیک گیاهی »

Hexaploid winter wheat (Triticum aestivum L., 2n= 6x= 42, AABBDD) is an important small-grain cereal crop grown for food and feed. In Iran, wheat is the most cultivated cereal crop where winter wheat is ranked 1st in terms of production. Wheat fusarium head blight (FHB) is one of the most important diseases of wheat in humid and hot regions of the world, which causes a decrease in yield and grain quality. Fusarium head blight is caused by Fusarium graminearum. In order to investigate the resistance of some wheat traits against HBF, 27 varieties and lines of bread wheat were sown at the farm of Faculty of Agriculture, Lorestan University. The spikes were infected at the first flowering stage by spray inoculation. The results showed that there was a great diversity among the 27 varieties of bread wheat tested in terms of growth traits, yield components, and grain yield. The results of The Duncan's test for comparing means showed that cultivars Ghods, Shiraz, Morvarid 2, and Pishtaz had a significant superiority in terms of grain yield compared to other cultivars. The results of simple correlation and also stepwise regression analysis showed that the traits of 1000 seed weight, plant height, number of seeds per spike, number of spikes, spike length and plant height are very important traits for grain yield. According to values of broad sense heritability and genetic gain for plant height and high correlation of this trait and seed yield, plant height can be used as a suitable trait for improving seed yield by selection. The overall results showed that Shiraz, Pishtaz, Quds and Morwarid-2 cultivars are suitable for transferring resistance to wheat spike blight disease in breeding programs.

To investigate the genetic structure of different sesame traits, 7 genotypes, including Ardestan, Sirjan, Fars, Sabzevar, Jiroft, Oltan and TS-3 were studied in the form of a 7 x 7 one-way diallel design in the research farm of the Faculty of Agriculture at University of Birjand during 2015-2018.The traits measured included plant height, height to the first capsule, number of auxiliary branches, number of leaves, leaf length, days to 50 % flowering, days to 90 % flowering, days to physiological maturity, number of capsules per plant, biological yield, grain yield, harvest index, number of seeds per capsule, capsule weight, capsule length, capsule width, chlorophyll a, b and total chlorophyll, oil and protein percentage.Hayman′s variance analysis showed that there were significant components a, b and b3 in all traits and components b1 and b2 in most traits. Parameters D, H1, and H2 were significant and the parameters F, h2 and E were not significant for most traits. The average degree of dominance (√H1/D) showed incomplete dominance and over dominance for all traits. The H2/(4H1) parameter was less than 0.25 in all traits except the day to 50 % flowering, suggesting that increasing and decreasing genes did not have symmetrical distribution among the parents. The parameter (√(4DH1)+F)/√(4DH1)-F ) showed symmetrical and asymmetrical distributions for the studied traits. In most of the traits, there was a dominant gene block controlling the traits. Broad sense and narrow sense heritabilities ranged 0.47-0.99 and 0.17-0.98, respectively. In general, all traits were controlled by genes with additive and dominance effects, so it is possible to select and produce hybrids in sesame. Considering that Fars, Oltan and TS-3 genotypes had the most dominant alleles, it is recommended that in future studies, attention should be paid to these three genotypes.

Eggplant is a highly nutritious vegetable that is widely consumed. The aim of this study was to evaluate the genetic diversity between eggplant accessions from the National Plant Gene-Bank of Iran. In the first year, a preliminary evaluation was conducted using 168 accessions. Based on preliminary evaluation results, 40 accessions were selected for complementary evaluation in the second year. The evaluation was based on 23 quantitative and qualitative traits. The results of the preliminary evaluation showed statistically significant (P<0.01) differences between accessions for all traits. Fruit shape frequencies were rounded (35.89 percent), elongated (32.18 percent), oval (13.67 percent), Semi-elongated (13.15 percent), and mace-shaped (5.11 percent). In the complementary evaluation, there were significant differences between accessions for all traits. Qualitative traits such as flower color (1.56) and fruit shape (1.53) exhibited the highest genetic variation, while fruit color (0.5) showed the lowest. Cluster analysis analysis results revealed four groups for accessions and the highest (22.34) and least (0.12) genetic distances between 1 and 2 and between 7 and 21accessions, respectively. Factor analysis showed that the first three factors explained 68.06 percent of total variation in data. The first and second factors were related to yield and yield components, respectively. Also, fruit yield traits showed high heritability and there was significant genetic correlation between these traits. Therefore, high heritable and high-scoring traits in these factors should be considered when selecting progenies in segregating populations for improvement in terms of fruit yield and shape.

Considering the importance of maize production and the impact of water deficit stress on reducing the yield of maize, estimating the genetic components and heritability of traits for determine the breeding method under water deficit stress is essential in breeding programs. The generations drived from a cross between two inbred lines of maize including B73 (maternal line) and MO17 (paternal line), SC704 (F1) as well as F2, BC1, BC2 and F3 generations in order to estimate the genetic effects and heritability of yield, yield components and morphological traits were studied. Seven maize generations using the generations mean analysis under the full irrigation, mild and severe water deficit conditions were evaluated. The experiment was conducted in the form of randomized complete block design with 20 replications per experimental unit during two cropping seasons (2018-2019) at the Agricultural Research Station of University of Tabriz. The results of two-year combined analysis of variance and mean comparisons under three different irrigation regimes showed that water deficit stress significantly reduced all of the studied traits (except root/shoot ratio). The generations mean analysis showed the high contribution of non-additive gene effects for the genetic control of grain yield, ear diameter, number of kernel row, ear weight (in full irrigation conditions), 100 grain weight, plant height, fresh shoot weight and biological yield traits. According to these results, selection in the advanced generations and the breeding method based on hybridization can be effective to improve these traits. Also, the significant contribution of additive gene effects in controlling the inheritance of ear length, ear weight (in both stress conditions) and root/shoot ratio traits indicated that selection in early segregating generations and inbred parents can be effective for breeding of these traits and taking advantage of additive variance. Hybrid SC704 and inbred MO17 compared with the inbred B73 showed the lowest variation percentage under the water deficit stress conditions, which indicated their high yield potential and stability in the stress conditions.

In order to determine the heritability and genetic parameters of physiological traits related to salinity stress in barley (Hordeum vulgare L.), a 7×7 half diallel cross was conducted at Islamic Azad University, Ardabil, during 2016-2017. The F1 seeds along with their parents were grown in greenhouse under non-stress, 8 and 12 dS/m salinity stress levels. After exposure of plants to salinity, leaf chlorophyll content, chlorophyll fluorescence and stomatal conductance were measured. Narrow sense heritability of chlorophyll content ranged from 0.29 to 0.40. These values for chlorophyll fluorescence ranged from 0.16 to 0.24 and for stomatal conductance ranged from 0.26 to 0.54. Broad sense heritability of traits was high and ranged from 0.70 to 0.87. The degree of average dominance was higher than one in all of traits, indicating the presence of over dominance in control of the traits. Dominant alleles were favorable, in stomatal conductance however such relation was not observed in leaf chlorophyll content and chlorophyll fluorescence

In a breeding program, knowledge on the effect of genes plays a key role in designing breeding programs and realizing effective selection. In this study, the breeding value for 17 traits in maize was estimated by using SNP markers data via Best linear unbiased prediction (BLUP) method. Among the studied genotypes; genotype 25*/89 in terms of date to emergence of male flowers, genotype P13L2 in terms of chlorophyll content had the highest breeding values. Genotype S2/QPM/SUKMA (Indonesia) in terms of plant dry weight, leaf length, plant height and genotype R59 (Paternal) in terms of first cob emergence date and genotype 1264/1 in terms of second cob emergence date had the highest breeding values, respectively. Genotype Kahia P16L4 showed positive and high breeding value in terms of grain weight per plant. P11L7 for cob number, P9L6 for cob length, P10L5 for leaf width, leaf area index, diameter of beginning part of cob, middle diameter of cob, cob weight and plant height had the highest breeding values. Considering the total breeding values of the studied traits, genotypes such as P10L5, P16L6 Kahia, P10L7, P10L9 had the highest rank. The estimated narrow sense heritability for the studied traits was in the range of 0.22 to 0.94. Genotypes with the highest breeding value have the highest ability to transfer their traits to offspring. Therefore, they can be used as a desirable parent to modify these traits in crop breeding programs.

Various strategies have been developed to reduce water consumption in rice cultivation, including rice cultivation in water-saturated soil, drying and wetting of the soil (periodic irrigation), and aerobic rice cultivation. In this study, in order to identify and grouping rice cultivars suitable for aerobic cultivation, 34 cultivars of native and improved rice cultivars were selected and evaluated. Factor analysis based on principal components analysis based on all traits showed that 6 factors were extracted with special values of more than one. These 6 factors, after the Varimax rotation, justify the 6 main and independent factors, justifying 78.08% of the total variation. In the first harvest, cluster analysis using WARD method, cultivars were grouped into 4 groups, which cluster 3 being the largest cluster. Discriminant analysis of first harvest, showed that all cultivars were grouped correctly. In canonical discriminant the first two canonical functions with eigenvalues greater than one explained a total of 88.9% of the variance. In cluster analysis based on the average of the data obtained from Raton product, genotypes were divided into two different groups. The genotypes of the first group were higher than the genotypes of the second group in terms of yield and yield components and were introduced as superior genotypes. Heritability with genetic improvement for leaf area duration, number of seedling (grown plants), number of spikes per unit area, number of full seeds and degree of maturity showed that these traits can be transferred to hybrid offspring and selections based on these traits are effective.

The study of the genetic structure controlling agronomic traits is one of the preconditions for selecting the appropriate breeding method. In order to analyze genetic of some agronomic traits of bread wheat using generation mean analysis, parents and different generations resulting from the cross of Marvdasht × MV-17 wheat cultivars were assessed in a randomized complete block design with three replicates under normal and terminal drought stress conditions in Research Farm of Razi University (Iran) during 2015-2016 cropping season. Based on the results of weighted ANOVA, a significant difference was observed between different generations for most of the studied traits under both conditions. Generations mean analysis revealed that in addition to the additive and dominance gene effects, a variety of epistatic effects also played a role in the inheritance of most traits, and therefore cannot hope for the success of selection in first generations. The role of additive gene effect was greater than the dominance one for plant height, peduncle length and awn length, indicating usefulness of using recurrent selection to aggregate these genes followed by selecting lines with favorable agronomic characteristics. The model of genetic control for most of the traits was similar under both conditions in terms of the presence or absence of non-allelic interactions and it has not been widely affected by drought stress. The broad-sense heritability for plant height, peduncle length and awn length was estimated to be high under both conditions. The broad-sense heritability for kernel yield was moderate estimated under both conditions, but the narrow-sense heritability was very low. In general, considering the greater role of the non-additive gene effect for most of the traits, the selection is suggested in advanced generations and after access to a high level of gene fixation.

Plant breeding researches is based on genetic diversity and evaluation of genetic diversity is also one of the most important steps in introduction of new cultivars. In this study, genetic diversity of 25 grass pea genotypes was studied based on randomized complete block design with three replicates in Khorramabad (Iran). Analysis of variance showed significant differences among genotypes for most of traits. Mean comparison showed that genotype IF1312 with the highest grain yield and genotypes IF1332 and IF471 with the highest dry and fresh forage yield had the best yield. Principal component analysis showed that the first 3 factors explained 62.64% of total variance. Based on cluster analysis, genotypes IF1307, IF1872 and IF471 with the highest grain and forage yield are belonged to one cluster. REML method was used to estimate genetic correlation and heritability of different traits. The highest amount of heritability (0.87) was estimated for number of immature grains and the least heritability (0.10) was estimated for total dry weight. Grain yield had a high and positive genetic correlation with forage yield, and biomass, percentage of leaf and dry forage yield also had a high and positive genetic correlation with fresh forage yield. Totally, genotype IF1307 had the best performance for most of traits compared to the other genotypes and had an acceptable forage yield among genotypes.

In order to determine the heritability and genetic parameters of some agronomic traits in barely (Hordeum vulgare L.) cultivars, a seven-parent half diallel (F1 crosses + parents) was conducted in the non-stress and salt stress (8 and 12 ds m-1) conditions in a randomized complete block design with three replications. Genetic analysis was performed by Hayman’s method and Griffing’s fixed model, method 2. The slope of linear regression of Wr on Vr were significantly higher than 0 and had not significant difference with 1 indicating the additive-dominant model was satisfied in all cases. The narrow-sense heritability of traits was medium to high (0.4-0.8) but their broad-sense heritability was estimated relatively high (0.7-0.9). Results of regression graphs showed that Afzal parent had the most dominant allele. The significance of “a” component in most of the studied traits indicated the presence of the additive effects in controlling of traits. The significance of “b” component in most of the studied traits indicated the presence of the dominance effects in controlling of traits. The proportion of positive and negative genes was lower than 0.25 in all of the traits (except for grain weight per spike in 12 ds m-1 salinity), indicating the presence of asymmetry in the distribution of the positive and negative alleles in the parents. Based on general combining ability effects, it was concluded that under salinity, cultivar “Kavir” had favorable alleles in plant height, grain weight per spike and 100 grain weight traits and can be used as a general parent in breeding programs. Estimates of high broad-sense heritability and narrow-sense heritability in most traits indicated that these genetic materials were promising for breeding under normal and salinity stress conditions.

This study aimed to estimate the genetic parameters of Haloxylon ammodendron located in the seed orchard of Yazd province, Iran, using REML method and repeatability model. For this purpose, among the stands of black saxaul in Yazd province, several rootstocks with suitable appearance, desirable quality, the relative balance between crown and trunk, resistance to pests and diseases selected and their seeds were sown in nursery, and the seedling were planted in the field based on a completely randomized design with unequal replications, 6 to 20 seedlings. The genotypes of each rootstock were planted on rows at 6-m intervals. Data collected and genetic parameters estimated for seedling traits as tree height, canopy expansion, trunk diameter, number of sub-branches, and freshness. Data were analyzed of variance using REML method, two different repeatability, and non-repeatability models. The results based on both models showed that the highest heritability was related to tree height. But these estimates between two methods were different so that, the genetic correlations and heritability values in the repeatability model were significantly lower than that for non-repeatability model. Repeatability was estimated based on the intragroup correlation between two independent variables on individuals and expressed as the ratio of differences between individuals to the existing phenotypic differences. Based on the results, the repeatability of the most traits was high. This result enables breeders to make good decisions about keeping rootstocks in the seed orchard during the growth stage in the early years. Finally, it was concluded that the repeatability model, could estimate moderate heritability for all of traits, which is more in line with the reality and quantitative nature of the studied traits and they could be mare affected by the environment factors.

In a breeding program, it is important to find out information about the genes action, because knowledge in this field could help the researchers in their crossing programs and realizing effective selection. In this study, breeding values of different agronomic traits in oriental tobacco were predicted using the best linear unbiased prediction (BLUP) procedure. For this purpose, 89 tobacco genotypes were evaluated in a randomized complete block design with three replications under normal (without broomrape) and stress (with broomrape) conditions at Urmia Tobacco Research Centre, during two successive years. Broomrape stress was applied by mixing 0.06 gr broomrape seed with soil in pots. C.H.T.209.12e × F.K.40-1 genotype had high yield under both normal and broomrape stress conditions and was one of the desirable genotypes in terms of yield tolerance and stability index. The Rustica genotype was the best genotype in terms of the breeding value of most of studied traits in both normal and broomrape stress conditions. The result from cluster analysis based on the breeding values of the studied traits showed that, tobacco genotypes were divided into 6 and 5 groups in normal and broomrape stress conditions, respectively; but the distribution of genotypes within the groups was different depending on the conditions. The highest heritability was observed for root fresh weight under normal condition and for leaf fresh weight under broomrape stress conditionss. The results showed that a genotype with good phenotypic performance may have low breeding value. Therefore, considering breeding value information along with phenotypic mean of traits can increase the efficiency of breeding programs.

Tall fescue (Festuca arundinacea) is one of the most important forage plants in the Gramineae family. Due to its resistance to salinity, drought, heavy metals, excessive grazing, as well as preventing soil erosion, tall fescue can be an appropriate choice for large-scale cultivation in Iran because of recent droughts and declined rangelands area. In the present study, the genetic diversity of 90 tall fescue populations was evaluated using 10 morphological and yield related traits including; canopy diameter, days to flowering, days to pollination, plant height, panicle length, collar diameter, number of stems, leaf length, dry forage yield and seed yield in Basmanj region, Tabriz (East Azerbaijan), Iran, during 2015 to 2017. According to the mean of the populations,there were significant differences (p < 0.01) among populations for all of studied traits except for canopy diameter. The results of correlation coefficients revealed that the number of stems, peduncle length, collar diameter and canopy area had a positive and significant correlation with dry forage and seed weight. The heritability of all studied traits was moderate to high. The highest heritability was related to seed yield, dry forage yield and flowering date, respectively. Based on the results of cluster and principal component analyses, studied tall fescue populations were divided into two main groups of ornamental and forage and four clusters (clusters I and II including early- and late-maturing forage populations and clusters III and IV including ornamental populations). The cluster IV included ornamental populations showed the highest difference and genetic distance with cluster I including forage populations and then more heterosis is expected by realizing cross between them. The results showed that the populations investigated in this study had the necessary diversity to running tall fescue breeding programs and can be potentially used in future breeding programs of this plant.

After cereals, oilseeds are the second-largest food reserves in the world. According to available statistics, more than 95 percent of Iran's oil needs are imported. Given the growing need for edible oils in Iran, it is important to identify fatty acids in the oilseed crops. Camelina sativa L. is an oil-medicinal plant and belongs to the Brassicaceae family that requires very little water and fertilizers. It is known as a low input plant. In this study, to analyze the fatty acid profile for breeding programs and specific industries, 137 doubled haploid camelina lines were evaluated in terms of fatty acid composition and variability of fatty acids trait, to estimate phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability, and expected genetic advance. The determination of fatty acid by gas chromatography showed that 18 types of fatty acids were detectable in camelina seed oil. It is shown that the two fatty acids (C14:0 and C16:1) have the highest PCV and GCV. The highest heritability for C20:2, C20:3 and C20:0 fatty acids was estimated 98.92, 98.59 and 96.49 percent, respectively. In this study, two lines with linoleic acid of 35.81-36.67% and four lines with values ranged from 22.08-23.00% were introduced. The ratio of omega-6 to omega-3 (0.479-0.759) was obtained in the studied lines.

Wheat is mostly cultivated at rainfed condition in Iran, so, water deficit stress has much effect on yield reduction. Hence, breeding activities are necessary for introduction of wheat tolerant genotypes to water deficit stress. In order to estimate the heritability and genetic correlation between traits of 36 wheat genotypes, an experiment was conducted in two separate conditions (water stress and non-stress) based on a randomized complete blocks design with three replications. Studied traits in wheat genotypes under water stress and normal condition showed significant differences for environment, genotype and genotype× environment interaction at 1 and 5% level of probability. The results of the factor analysis showed that the 6 first factor in normal condition explained 81.13% of total variance, and the 5 first factor in stress condition explained 74.96% of total variance. Estimation of genetic correlations based on REML approach revealed that biological yield, harvest index and number of grains per spike had the highest correlation with grain yield and these characteristics are of important for selecting the varieties with high yield under non-stress and stress conditions. Estimation of heritability based on REML approach showed that number of days to heading had the highest amount of heritability in both normal and stress conditions.

In order to estimation genotypic correlation and heritability of some faba bean traits, 26 faba bean genotypes were evaluated in a randomized complete block design with three replications during 2014-16 growing seasons in Agricultural Research Sation of Borujerd located in Lorestan province, Iran. The restricted maximum likelihood (REML) was used to estimate the genotypic and phenotypic correlations, broad sence heritability and genetic gain. Analysis of variance based on least squares and REML indicated significant effect of genotype on days to maturity, plant height, hundred seed weight, pod length and dry seed yield. Genotype×year interactions were significant on all of the traits except of pod length. Borujerd cultivar (G26) and G20 had the highest dry seed yield in both of years. REML results indicated a significant positive genetic correlation between dry seed yield and biological yield and plant height. Also, there were a significant negative phenotypic correlation between dry seed yield and days to maturity, and significant positive phenotypic correlation between dry seed yield and plant height, biological yield and harvest index. So, the selection of early maturing genotypes with a higher yield is achievable and selection can be done to improve the performance of dry seed yield. Cluster analysis indicated variability among genotypes. According to values of broad sence heritability and genetic gain for plant height and high genetic correlation of this trait and dry seed yield; plant height can be used as a suitable trait for improving dry seed yield by selection.

Amygdalus scoparia spach. a multi-purpose species which is growing in most of vegetation regions of Iran. Knowledge of genetic variability and heritability is essential prerequisite for conservation, forest development and sustainable use of forest plants. Genetic parameters on early growth were estimated in open-pollinated combined provenance-progeny tests. The experiment was conducted based on a nested model using randomized complete block design with 7 population, 10 mother trees per population 7 individuals per subplot and 3 replications in nursery of Kohmareh-Sorkhi of Fars (1660 m a.s.l.). Significant differences among the populations and mother trees within populations were observed for all of the studied traits, except for the taproot length among mother trees within populations. Evaluation of components of variance showed that the population effects (ranging from %5.9 to % 34.2) contributed to total variance more than mother trees within populations effects (ranging from%1.8 to %11.1). Additive genetic variation coefficient in populations varied from 0 to 58.6%. In general, Khonj and Kavar populations performed better growth. Heritability was low and not yet stable for some traits in some populations. Therefore, selection should be postponed until the heritability values reach to relatively high and stable values.

Drought stress is one of the factors that reduces yield in the world. Considering that wheat is grown mostly in semi-arid areas, much attention has been paid to develop drought tolerant varieties. This experiment was conducted during 2013-2014 in Tabriz University research farm, Iran. In this investigation the inheritance of some agronomic and physiological traits was studied in the field condition through generations mean analysis. The generations were produced from the cross of Arg (tolerant to drought) and Moghan3 (sensitive to drought) varieties. The experiment was a split plot design based on randomized complete blocks with two replications. The irrigation conditions were arranged in the main plots and generations in the subplots. In the stress condition, irrigation was withheld after pollination. Based on the analysis of variance, significant difference were observed among different generations in terms of plant height, peduncle length, flag leaf length, flag leaf width, number of fertile tillers, leaf chlorophyll content, leaf temperature, days to maturity, spike weight, straw weight, biomass, grain yield and harvest index. The interaction between generations and irrigation conditions was significant only for grain yield. The generation mean analysis in both normal and drought stress conditions showed that chi-square of three parameter model was significant for all of the studied characteristics, indicating the presence of non-allelic interactions in the inheritance of these traits. The broad sense and narrow sense heritabilities for the traits under study were estimated as 0.502-0.946 and 0.244-0.429 in the normal condition and 0.653-0.951 and 0.221-0.377 in the water stress condition, respectively. The average degree of dominance for all of the characters in both normal and water stress conditions was greater than one which indicated the existence of over-dominance gene action in controlling these traits. At both conditions, the dominance genetic variance was higher than the additive genetic variance for all of the traits. The results indicate the necessity of selection in advanced generation or exploiting dominance gene action in the breeding programs, if hybrid varieties are produced in the wheat plant.

Drought is a worldwide risk seriously influencing production of agricultural plants such as coriander. In order to evaluate heritability and gene action for important quantitative traits in coriander in three irrigation regimes, including well water (WW), mild water stress (MWS) and severe water stress (SWS), a cross between two genotypes of TN-59-158 (Sensitive parent) and TN-59-230 (Tolerant parent) was done. Parents and progenies of triple test cross were evaluated in filed condition through a randomized complete block design with three replications. Days to 50% flowering (DTF), days to harvest (DTH), fruit yield (FY), thousand fruit weight (TFW), harvest index (HI), relative water content (RWC), essential oil yield (EOY) were measured. Results showed that total epistasis effect was observed for all traits except RWC in WW. Also, total epistasis effect was observed for all traits except DTF in MWS and SWS. Partitioning of total epistasis revealed that [i] type of epistasis was contributed to determining DTF and TFW in WW and MWS treatments, DTH, FY and RWC in MWS and SWS treatments, and HI and EOY in WW, MWS and SWS treatments.