جستجوی مقالات مرتبط با کلیدواژه "اپیستازی" در نشریات گروه "زراعت"

Gynociouce hybrids have the advantage of high yield; therefore, gynociouce trait should always be considered in the production of cucumber hybrid cultivars. There are at least five genes that affect the expression of gynociouce. In order to improve cucumber for production new cultivars with higher yield and better quality, using of genetic diversity and cucumber germplasm is extremely essential. Knowing the importance and extent of controller genetic effects the inheritance of traits can lead to the selection of appropriate corrective methods. Therefore, the present study took with this goal how inheritance of the gynoeciouc trait and to investigate the effects of controller genes on this trait and other performance components in cross between a commercial hybrid and a selected line, Finally a proper amendatory plan is adopted.

In order to evaluate genetic and determinate heritability of gynoecioucy in cucumber seven generation including P1, P2, F1, F2, BC1, BC2 and F3 from a cross between two gynoeciouc and androeciouc cucumber lines N10×A11, were supplied and number of female flowers and number of male flowers, number of fruit per plant, length of plant and length of internode were evaluated in a randomized complete block design with three replications. Cause on create populations, experiments were carried out in the spring and autumn of 2017 to 2018 in three stages in the greenhouse of the college of Agricultural Sciences, University of Guilan and population assessment was performed in 1398 in the research farm of the Faculty of Agricultural Sciences, University of Guilan. First year, in order to produce hybrid seeds, a cross was made between gynoecious N10 and androecious A11 lines. After producing and cultivating hybrid seeds in the second stage, self-pollination and hybrid cross-breeding with parents were carried out and F2 populations and backcrosses were created. In the second year, samples of second generation seeds were planted in greenhouses for creating self-pollination and third-generation populations. In the greenhouse, hydroponic cultivation system was used and fertilization and irrigation of plants were did at regular intervals. In the field cultivation system, Growing Phases were carried out using drip irrigation system and cover mulch for planting and necessary agricultural care in the cultivation stages. Data normality was tested by SPSS software and data analysis was performed by SAS software. Generation mean comparison was also performed using LSD test at 5% and 1% probability levels.

about the gynoecioucy there was a significant differences among case study generations. Examination of scale tests for this trait also showed that there may be inallele interactions among the genes controlling this trait. Examination of genetical parameter and doing scale tests showed for all of study traits there are different epistasis. the results showed about number of female flower all of the genetic parameters was significant and for number of male flower, number of fruit per plant and length of internode traits simple six parametric was in charge of controlhing the traits such as all of genetic parameters without dominance-dominance epistasis, whereas for length of plant trait simple six parametric model such as all of genetic parameters without additive-additive epistasis was the best of genetic model vindication for diversity.

Evaluation of inheritance and dominance degree showed additive variance was more important in number of female flower and number of fruit per plant traits that means Superior genotypes can be select to modify these traits in the study population

Studying the genetic structure of crops, including wheat, has always been one of the research priorities to increase the efficiency of breeding methods. In order to genetic analysis of some agronomic traits of bread wheat using generation mean analysis (GMA), all produced generations along with relevant parents of the two populations (Marvdasht × Rasoul and Marvdasht × Shahpasand) were evaluated in a randomized complete block design with three replicates under normal and terminal drought stress conditions in Razi University during 2015-2016 cropping season. Weighted analysis of variance showed the significant differences among generations for the most of the traits in two conditions. The results of GMA revealed that although the mode of inheritance differed in the crosses for the most of the traits, but additive, dominance gene effects and different types of epistasis had the roles in the heritability of the most traits. Among these gene effects, the role of dominance gene effect was higher and therefore, selection should be delayed to later generations. However, the role of fixable gene effects in the heritability of the traits such as stem diameter, awn length and number of spikelets per spike (both crosses), plant height and peduncle length (Marvdasht × Shahpasand), was almost equal or more than dominance gene effect indicating the usefulness of selection in early generations for these traits. The broad-sense heritability for kernel yield was estimated as nearly moderate for both crosses under both conditions, but the narrow-sense heritability was low under both conditions. Results of analysis of variance obtained from regression method showed that fixable-gene effects had higher relative contribution of generation sum of squares for most of the traits than non fixable-gene effects at both crosses under both conditions. The model of genetic control for the most of the traits was similar under both conditions for both crosses and it has not been widely affected by drought stress.

Rice grain appearance quality traits (APQ) affect consumer preference and marketing acceptance and long grain rice has many customers on the international markets.In order to identify QTLs controlling grain length, width and length to width ratio (shape) and QTL by environment interactions a study was conducted on two set of recombinant inbred lines (RILs) of two rice populations derived from crosses of Alikazemi / IR67017-180-2-1-2 (ALIR population) and Alikazemi / Saleh (ALSA) cultivars.The treatments of each RIL population with five check varieties were evaluated in augmented based on randomized complete block design with 5 replications in two regions of Rasht and Tonekabon in northern of Iran. Linkage map of the two populations using 87 polymorph microsatellite markers (SSR) covered 1356.0 cM of rice genome with an average distance of 15.58 cM between two markers. In this study, a total of 13 main QTLs (M-QTLs) and 10 pairs of epistatic QTLs (E-QTLs) were identified for three above mentioned traits, including seven M-QTLs and five pairs of E-QTLs for the ALIR population and six M-QTLs and five pairs of E-QTLs for the ALSA population. Two QTLs, qRGL4 (1.1) and qSGL5 (1.01), were increased the grain length with positive additive effect and the highest justified phenotypic variance of 25.2 and 18.4%, respectively. In this study, three QTL clusters were identified for APQ traits. Of these, two clusters were identified on chromosome 3 that was effective in controlling all APQ traits in two populations with alleles from a common Alikazemi parent. The third QTL cluster was determined on chromosome 7 consisting of qGW7 and qGSh7 for grain width and shape in the ALIR population. Therefore it could be stated that the QTLs on each cluster were either tightly linked or had pleiotropic effects with considerable influences in controlling rice APQ traits. A common marker of RM5955 was found in the ALIR population with a genetic distance of about 3.7 centimeters with QTLs of all three traits, and could be considered as a linked marker in breeding program. In this study, ten pairs of E-QTL were identified for three traits including five pairs per population. The epistatic effects in the ALIR population were mostly expressed by significant main QTLs (80%), while they were expressed in the ALSA population more by non-detected main QTLs (60%).The contribution of explained phenotypic variances of M-QTLs in controlling APQ traits were more than epistatic QTLs. QTL by environment interactions revealed that only one main QTL had significant interaction with environment, while no epistatic QTLs with additive × additive effect were found to be interacted with environment. The appropriate QTLs and linked markers in this study can be used in the breeding program to improve the appearance quality of rice grains after fine-mapping and validation.

Brown wheat rust caused by Puccinia recondita f. sp tritici is one of the most important diseases of wheat in most parts of regions in the world. The progeny of F1, F2, BC1 and BC2 derived from cross of Bolani×ATRI525 and Bolani×ATRI527 with parents, were cultured in a completely randomized block desigen for the study of wheat rust resistance. Trait such as infection, Infection type, contamination coefficient and surface under the disease progression curve were measured and evaluated. Genetic analysis by analysis of means and variance of generations showed that in addition to increasing effects, epistatic effects also play an important role in the control of traits. However, dominance variance had an important role in the control of traits in the incremental variance and there was a significant difference between the generations in terms of all traits in the one percent (P<0.01) level. The results of genotyping average analysis indicated that the dominance of genes was the most important genetic factor in control of the studied traits. Epistatic additive×additive incremental addiction was more important than the epistatic dominance×dominance. The average of heritability for the traits was the percentage of infection, type of contamination, contamination coefficient and under curve of disease progression were 0.88, 0.92, 0.82 and 0.86 for the first population and 0.75, 0.68, 0.62 and 0 59 for the second population. Private heritability for the above mentioned traits was varied by 0.42, 0.34, 0.52 and 0.17 for the first population, and 0.45, 0.39, 0.46 and 0.19 for the second population. The mean genetic dominance (√(H/D) was less than one for all four attributes, indicating the role of dominance effects in trait control.

Take-all disease, caused by Gaeumannomyces graminis var. tritici (Ggt) is one of the most important of wheat diseases that causes severe damage to crown and root rot in different regions of Iran. Development of resistant varieties requires genetic study on inheritance and type of gene action in disease resistance, which so far has not been any report in relation to (Ggt). Therefore, in order to genetically analyze of resistance to this disease, the generations of P1, P2, F1, F2, BC1 and BC2 were produced and planted at greenhouse. After artificial infection of plants with T-41 strain of (Ggt), the phenotypic measurement was based on the degree of disease damage and its symptoms on the crown and root were recorded. The results of the generation mean analysis indicated that the five-parameter model can explain the variations between the means of generations in two crosses (1528×164 and 1622×1526) and four parametric models in third cross(1528×1546). Additive, dominance and epistatic effects including additive × dominance and dominance × dominance were exist in controlling of this trait. The dominance and epistatic effects were greater than the others. Distribution of F2 generations, showed a tendency toward susceptibility so the susceptibility was dominant to resistance. Analysis of the F2 data based on the classical ratios showed that with phenotypic grouping of F2 generation in three susceptible, semi-susceptible and resistant groups. These three groups corresponded to the epistatic ratio (9:6:1), respectively. This result was almost consistent with the results obtained from the Generation means analysis, since in GMA, duplicate dominant epitasis and partial duplicate interaction were detected and the minimum number of genes involved in controlling this trait has been estimated by 2 gene that it has a relative accordance by duplicate dominant interaction with additive effect (9:6:1).

In order to study the type of action of genes and inheritance of traits in chickpea, the generation mean analysis was accomplished using the cross of six cultivars of chickpea called Pirouz, Bivanich, Flip51-87c, Iccv2, Kaka, and Azad. Parent seeds along with seeds of F1, F2, BC1, and BC2 were cultivated in a randomized complete block design with three replications, and eight traits including plant height, number of seeds per plant, number of pods per plant, number of hollow pods per plant, number of double-grain pods per plant, 100-seed weight, number of days to 50% flowering, and grain yield were evaluated. The variance analysis results indicated that the mean squares of generations were significant for all the traits, so the generation mean analysis for the studied traits was performed. Based on the results of generation mean analysis for all the studied traits besides the additive and dominant effects, epistatic effects were also fitted which indicates the complexity of the inheritance of these traits. The results also showed that the plant height was controlled by incremental and dominating effects. It was also determined that the dominant genetic effect has the most significant role in the inheritance of most of the studied traits.

Take-all is one of the most important diseases of wheat in wet areas, causing significant damage in these areas, and there has not introduced any resistant varieties against this disease until now. Therefore, efforts to identify the resistance genes to this disease and developing resistant varieties or cultivars with lower susceptible in bread wheat have a great importance.In this research, in order to identify the markers related to resistance to a isolate of take-all (T-41), a population of F2 derived from crosses of susceptible genotypes (1546 and 164) with resistant genotype (1528) and bulk segregate analysis (BSA) where used. After planting the F2 population and parents in the greenhouse and artificial infection the plants with the fungus, the plant phenotype was determined according to the amount of contamination by scoring. After DNA extraction of parents and F2 population, two bulk of DNA was prepared from resistant and susceptible individuals based on disease scores. The bulks and parental DNAs where analyzed by RAPD, SCoT, ISSR and SSR primers and PCR reaction. Among the primers are used, only one ISSR primer produced a band of 400 bp in the resistant parent and bulk which was not found in the susceptible parent and bulk. Then, all individuals of bulks and F2 where genotyped for this marker and regression and chi-square analysis showed a significant relationship between this marker and the disease score. The regrsion of disease score on band 400bp (b = -0.709) indicates that this band is more abundant in low scores (resistant individuals). Also, the distribution of F2 individuals in one of the crosses confirmed the existence of the epistatic (9sensetive: 6 semi sensitive: 1resistance) relationship

Rice yield as a complex trait is the main target in most rice breeding programs. To map the main and epistatic QTLs controlling grain yield and yield components, an experiment was carried out using a 129 F6 recombinant inbred lines population (IRA population) originated from a cross between Alikazemi / IR67017-180-2-1-2, in 2015 growing season in two locations, Rasht and Tonekabon, Iran.  The experimental design was augmented design arrangment with five check cultivars in randomized complete block design with five replications. Analysis of variance showed that the linkage map consisted of 87 Single Sequence Repeats (SSRs) covering 1356.0 cM of rice genome in 12 linkage groups with an average distance of 15.58 cM spamming two markers. The results of combined analysis of variance for two locations, using composite interval mapping method, identified a total of 13 main QTLs on rice chromosomes for five measured traits. The qTN3 with 13.9% for tiller number per plant, the qFG4 with 11.6% for filled grain per panicle and the qGY6 with 15.6% for grain yield had significant positive additive effect. Furthermore, the qSG1 with 19.9% phenotypivc variation had a negative additive effect on the number of unfilled grain.panicle-1. These finding suggest that these QTLs can be used in rice breeding programs for improving grain yield. The interaction between additive effect (A) of QTLs and environment (E) was significant on grain yield and number of unfilled grain.panicle-1, but it was not significan on other traits. A total of 18 QTL pairs with significant additive × additive (AA) epistatic effect were identified for all traits. The highest epistasic effects were related to grain yield and number of unfilled grain.panicle-1 with six pairs of QTLs for each of these traits. Only one of the epistatic effects between qSG1-2 and qSG6 had significant AAE effect with a R2aae = of 3.4%. In addition, some QTLs were identified as three gene clusters controlling the grain yield, number of tiller.plant-1 and number of filled grain.panicle-1. Furthermore, five microsatellite markers including RM7551, RM8218-RM3417 and RM5302- RM283 0.2 to 5 cM distance from were identified as linked markers with qGY6, qFG4 and qSG1, respectively. These markers can be considered in the marker-assisted rice breeding program.

To detect main and epistatic QTLs and their environmental interactions for rice important agronomic traits, 242 recombinant inbred lines (RIL) from two F6 rice populations derived from crosses between Alikazemi / IR67017-180-2-1-2 (IRA population) and Ali Kakami / Saleh (SA) cultivars were evaluated in two locations. Results of the present experiment showed that the linkage map of the two populations using 87 polymorph microsatellite markers (SSR) covered 1356.0 cM of rice genome with an average distance of 15.58 cM between two markers. A total of 20 main QTLs (M-QTLs) and 33 epistatic QTLs (E-QTLs) were identified with positive and negative effects. Five M-QTLs and five E-QTLs had a significant interaction with the environment. Eight M-QTLs and ten E-QTLs with significant effect on agronomic traits were stable and did not have any significant interaction with the environment. These QTLs include two M-QTLs and two E-QTLs for reducing plant height, three M-QTLs and three E-QTLs for decreasing heading date, an M-QTL and an E-QTL for increasing panicle length and two M-QTLs and four E-QTLs to increase grain yield. These main QTLs explained 11.12% (qHD6) and 24.5% (qGY1) phenotypic variation, respectively. Therefore, such useful QTLs can be used for gene pyramiding programs to improve rice agronomical traits. Furthermore, six linked SSR markers (RM421, RM178, RM3441, RM5101, RM7551 and RM5302) were identified with less than 5 cM distance from important QTLs, suggesting that such SSR markers can be used in marker-assisted selection to select rice lines with desirable traits in segregation generations.

In order to identify genomic regions with main, epistatic, and QTL×environment interaction effects for some of the phenological and morphological traits in bread wheat, an experiment with 167 recombinant inbred lines and their parents (‘SeriM82’ and ‘Babax’) was conducted at Research Farm of the Agricultural Research Station of Sistan in 2015-16 cropping season. The experiment was carried out using two alpha lattice designs with two replications under non-stress and terminal heat stress conditions. Seven traits including days to maturity (DM), grain filling duration (GFD), maximum quantum efficiency of photosystemII (Fv/Fm), cytoplasmic membrane stability (CMS), grains per spike (GPS), grain yield (GY) and thousand grain weight (TGW) were measured. There were significant differences among the genotypes for all studied traits and maximum correlation was observed between GY and Fm/Fv (r = 0.86**). QTL analysis was conducted by Mixed-Model based composite interval mapping (MCIM) method. A total of 33 main-effect QTLs for studied traits were detected. Phenotypic variances explained by these QTLs varied from 7.04% for GFD to 19.41% for TGW. The major Qtgw7D (R2 = 19/41) was identified near the marker of acc/cat-10 and after validation can be used in marker-assisted selection (MAS) in order to produce heat tolerant wheat varieties.

To determine the type of genes action and estimate genetic parameters under moisture stress condition, two inbred lines of S0200237 (P1) and ILYH0231 (P2), sensitive and resistant to moisture stress, respectively, were crossed in 2013. Six generations P1, P2, F1, F2, BC1 and BC2 were planted in a randomized complete block design in 2015 and generation mean analysis was performed. Significant and positive heterosis was observed for ear biomass/ plant and ear-grain yield/plant. The joint scale test and the average of gene dominance confirmed the inadequacy of the additive-dominance model for most traits, indicating the importance of epistatic and over-dominant effect in genetic control of the traits. The results showed that row number/ear, ear diameter, cob diameter and grain depth were controlled by additive effect. The broad and narrow sense heritability of the ranged varied from 68.9 to 88.6 and 13 to 50.40, respectively. The average of genes number controlling the traits varied from 1-7 genes for grain yield. The maximum positive heterosis was observed for ear biomass and grain yield per plant. Generally, selection in early generations for grain yield-related traits with high narrow sense heritability, including the number of rows per ear, will improve grain yield in advanced generations. In addition, selection in early generations to reduce cob percent, to some extent, does not result in a significant reduction in total ear weight, and will result in an increase in harvest index, thus improves grain yield under moisture stress conditions.

Early vigor is an imperative trait and its role become more important under drought stress condition. Genotypes with better early vigor cover above the soil plane, reduce evaporation of soil surface and increase weed competitiveness. In this research, a half diallel mating design was generated from crosses between seven bread wheat to study the genetic of early vigor. Parents and F1 progenies were planted in greenhouse in a randomized complete block design with six replications and seedling dry weight, seedling length and germination ability were evaluated. Additive and dominant effects significantly affected seedling dry weight and seedling length, while germination ability only affected by additive effect. Results showed that epistasis was significant for all traits. Seedling dry weight, seedling length and germination ability showed high broad sense heritability (0.95, 0.91 and 0.84, respectively). Meanwhile, seedling dry weight and germination ability showed low narrow sense heritability (0.29 and 0.19, respectively) and seedling length showed moderate narrow sense heritability (0.62). Selection in early generations has slow progress due to low narrow sense heritability and presence of epistasis. Consequently, bulk, single seed descent and double-haploid methods are suggested in breeding programs for improving early vigor. Iranian cultivar, Roushan, showed the best early vigor and general combining ability among evaluated cultivars and proposed as one of mating parents in breeding programs to improve early vigor.

Two BC2F4 populations of rice, Hashemi/IR67418-110-3222 (Hashemi/IR-22) and Hashemi/Neda, Hashemi was as recurrent parent, were studied during two years (2009 and 2010) for QTLs detection for plant height, days to 50% heading, growth duration and yield. The role of epistasis and QTL-environment interaction on these traits was also studied. Hashemi/IR-22 and Hashemi/Neda lines were tested with 61 and 65 polymorph SSR primer pairs, respectively, which were distributed on all chromosomes. The total genetic maps lengths of Hashemi/IR- 22 and Hashemi/Neda were 1103.45cM and 1260.53cM, respectively. Four to five QTLs were detected for each trait in Hashmi/IR-22 population with at least two QTLs repeated for each trait during two years. These QTLs explained 5.6% to 37% of the traits phenotypic variation. In Hashemi/Neda population three to four QTLs were detected for each trait, with at least one QTL repeated for each trait during two years. These QTLs explained 5.1% to 43.2% of the traits phenotypic variation. From detected QTLs, only a plant height QTL flanked by RM234 marker on chromosome 7 and a yield QTL flanked by RM3337 and were the same in the two populations. This indicated the important role of genetic background effect on controlling these traits. In each population there were QTLs that simultaneously affected two or more of the studied traits, e. g. plant height, days to 50% heading, growth duration and yield, which suggested pleiotropic or linkage gene effects for these traits. Two QTLs on chromosomes 6 and 8 for growth duration and QTL on chromosome 8 for yield in Hashemi/IR-22 population and one QTL on chromosome 6 for days to 50% heading and growth duration and one QTL on chromosome 3 for yield in Hashemi/Neda showed interaction with environment. Also in each population a pair of QTLs was recognized with significant epistatic effect.

In order to study the genetic control of resistance to common smut in maize, two resistant inbred lines, K1264/1 and K47/2-2-21 and two susceptible inbred lines, K3304/1-2 and K47/2-2-1-3-3-1, were crossed as K1264/1 × K3304/1-2, K47//2-2-21 × K3304/1-2 and K1264/1 × K47/2-2-1-3-3-1. The F1, F2, BC1 and BC2 progenies were produced and evaluated along with parents using randomized compelet block design with three replications. All generations were artificially inoculated with spordia of Ustilago maydis suspension. Inoculation was carried out 7-10 days after silking through injection of 3 ml of 106 spores/ml fungal suspension, using tip injection method. At maturity, disease severity was determined based on ears infection and analysed according to generation means analysis method for three crosses. Joint scaling test showed that the presence of additive, dominance and epistasis effects, especially additive × additive and dominance × dominance type, and in lesser extent, additive × dominance, in genetic control of resistance to maize common smut. Average broad and narrow-sense heritability based on three crosses data were estimated 80.3 and 57.3, respectively.

Choice of efficient breeding program depends on the knowledge of the genetic system controlling the character to be improved. To estimate the genetic parameters for yield, yield components and some other morphological traits in corn (Zea mays L.), B73×MO17 and B73×K74/1 crosses were studied by triple testcross method. The experiments were conducted at research field of Seed and Plant Improvement Institute (SPII) in 1999-2001. Significant differences were observed among means of F1 , P1 and P2 testcrosses for all of the traits in both crosses. The B73 testcrosses generally had greater means than MO17 and K74/1 testcrosses except for number of leaves in two crosses, cob weight in cross B73×MO17 and anthesis silking interval in cross B73×K74/1. B73 testcross seems to contribute significantly in the expression of positive epistatic effects. Epistasis effects were significant for all of the traits in both crosses. Partitioning of the epistasis effects into fixable and non-fixable components revealed that additive×additive effects (fixable) were not significant for the traits except for days to silking in both cross, anthesis silking interval and plant height in cross B73×MO17, but additive×dominance and dominance×dominance effects (non-fixable) were significant for all of the traits in both crosses.