مجله پژوهش های ژنتیک گیاهی
سال ششم شماره 2 (پاییز و زمستان 1398)

Dehydration is the most important limiting factor in agricultural production in arid and semi-arid regions, and water shortages (especially at the reproductive stages) due to lack of precipitation and unequal distribution are inappropriate for limiting the yield. In this research, cross between the Gasspard cultivar (dehydrated susceptible parent) and DN11 line (resistant parent) was performed. F1, F2, F3, BC1 and BC2 generations along with parents, were planted in a randomized complete blocks design with three replications in normal and water deficit conditions for two consecutive years. Physiological traits were measured for single plant samples. Weighted analysis of variance showed that water deficit stress caused significant decrease in flag leaf area and unsignificant decrease in stomatal conductance. Generation mean analysis for Chlorophyll index was accompanied by different results in terms of regression fitted models for each environment, but for stomatal conductance, the results of the generation mean analysis were the same in both environments. In addition to additive and dominant effects, epistatic interaction effects also played role in the inheritance of all studied traits. Most of these effects were double-effects. In flag leaf area, additive, additive × dominant and dominant × dominant effects were involved in inheritance. In water relative content, in addition to these effects, dominant effect was also involved in inheritance. Generations variance analysis showed that the gene action was additive for relative water content, dominant for flag leaf area and over dominant (in both conditions) for stomatal conductance. The gene action for Chlorophyll index under stress and normal conditions were over dominant and additive respectively.

Autumn sowing of sugar beet is a suitable way in sustainable agriculture. Bolting is an undesirable phenomenon which reduces sugar beet yield and it is the most important limiting factor in autumn sowing of sugar beet. Identification and comparison of the sequence of flowering genes in various genotypes can help to understand the molecular mechanisms controlling bolting. In the previous studies, it was revealed that expression level of FT1 and VIN3 genes in sugar beet is associated with bolting resistance. In this study, the sequence of FT1 gene promotor and three versions of VIN3 gene promoters of sugar beet were compared in three bolting resistant and three bolting susceptible genotypes. Primer design for each gene was carried out using the DNA sequences found at the NCBI database. DNA was extracted from leaf samples growing in pots and was used as template in PCR reactions. Similar length of amplified fragments for each promoter gene in bolting susceptible and bolting resistant genotypes were selected and sequenced for more accurate assessment. There was no mutation in the FT1 gene promoter, however 624 substitution and insertion/deletion mutations were observed in the promoter of three versions of VIN3 gene. A 228-bp ins/del region was detected in the VIN3-like1 promoter. This region contains promoter elements and seems to have a control function. Comparison of detected mutations between susceptible and resistant genotypes did not show a distinct pattern for bolting.

Increasing drought tolerance, especially in rice, which is one of the most important crops in Asia, is necessary. Transcription factors are specific sequence DNA-binding proteins that are capable of activating or suppressing transcription. These proteins regulate gene expression levels by binding to cis regulatory elements in the promoter of target genes to control various biological processes such as growth, cell division and response to environmental stresses. In this study, MAD8 and MYB93 genes that were involved in drought stress in rice were considered in two leaf and anther tissues at 0, 24, 48, 72 h and one week after stopping irrigation. The results of q-PCR analysis showed significant expression changes of these transcription factor genes under drought stress conditions. In this study, a significant increase in the expression of these genes at 24 h after drought stress in transgenic plants (Promoter region with accession: NC_029264.1 and GUS gene have transformed) compared to non-transgenic plants showed a relationship between these transcription factors and higher expression of transported promoter in transgenic plants.

The common fig (Ficus carica L.), one of the most important fruit species, belongs to Moraceae family and is widely distributed in Iran. In this study, genetic variations among some genotypes of common fig collected from six different regions of Ilam province (Iran) were evaluated based on RAPD and ISSR markers. A total of 73 and 29 alleles were produced by 14 RAPD (with their sizes ranging from 350 to 2500 bp) and 5 ISSR (with their sizes ranging from 150 to 1500 bp) primers, respectively. The number of observed alleles for RAPD primers ranged from 1 (OPA-03) to 9 (OPA-09 and UBC-429), with an average of 5.21 alleles per locus. Also, the number of observed alleles for ISSR primers ranged from 3 (UBC-807) to 8 (UBC-810 and UBC-414), with an average of 5.8 alleles per locus. The highest and lowest values of Shannon's information index (I) was observed in the UBC-429 (2.18) and OPA-03 (0.12) primers, respectively. The Jaccard's genetic similarity coefficient ranged from 0.12 to 0.73 among genotypes based on RAPD data, while for ISSR it was recorded from 0.07 to 1. Also, based on RAPD and ISSR data at a similarity coefficient of 0.45, the unweighted pair group method with arithmetic mean (UPGMA) cluster analysis divided the genotypes into six major groups. As a conclusion, there is a high genetic variability among fig genotypes, which is an important consideration for classification, utilization of germplasm resources and breeding programs of fig.

Genetic diversity is the basis of breeding studies in many plant species and is one of the most important indicators for selecting parents. The aim of this experiment was to investigate the genetic diversity of tall fescue (Festuca arundinacea) using agronomic traits such as plant height, spring growth score, days to flowering, days to pollination, flag leaf length and width, panicle length, weight of 100 seed and seed yield per plant. The experiment was carried out in a randomized complete block design with three replications. Based on the results, the ecotypes were significantly different for all of the evaluated traits with the exception of 100 seed weight. The highest phenotypic variation coefficient (58.66), genetic variation coeficient (58.32) and heritability (0.97) were related to plant height. The correlation between traits showed that ecotypes with higher height, panicle length and flag leaf height and spring growth score have higher seed yield. The results of stepwise regression analysis showed that in the regression model for seed yield per plant, the panicle length, alone, justified 60.95% of the variation. Cluster analysis grouped 25 ecotypes into three groups. Analysis of variance of agronomic traits as well as yield and related traits showed that grouping caused mean squares between groups in all traits (except flag leaf width). In this study, high genetic diversity and high heritability for evaluated traits showed the potentials of genetic improvement.

Biochemical and physiological traits are affected by environmental stresses and therefore the breeding of these traits will play an effective role in stress tolerance. In this study, hybrids of five S7 lines of maize in a 5 × 5 half-diallel design were investigated in order to study the combining ability of biochemical and physiological traits of maize at the Research Farm of Graduate University of Advanced Technology, Kerman, Iran during the 2017-18 crop year based on randomized complete block design with three replications. The results of analysis of variance by fourth Griffing's method showed that the general (GCA) and specific (SCA) combining ability variances were significant for protein, proline, sugar content, carotenoid, chlorophyll a, chlorophyll b and total chlorophyll traits. Therefore, the role of additive and non-additive effects was identified in controlling these traits. Protein, proline, chlorophyll a and total chlorophyll traits were more controlled by additive effects, whereas the carotenoid trait was more controlled by non-additive effects and the role of additive and non-additive effects in controlling other traits was almost equal. The KSC704-S7-11 line showed positive and significant general combining ability for most of the studied traits, suggesting this line can be used in breeding programs to improve and increase stress tolerance. In addition, P1 × P3 and P4 × P5 crosses showed the most positive and significant specific combining ability for proline, chlorophyll a, total chlorophyll and carotenoid traits; thus they can be considered as the best hybrids to improve and increase stress tolerance in corn.

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.

In this study, variation of beta-glucan content was assessed in 20 barley line and cultivars based on complete block design with three replications. Genetic diversity of these genotypes was also evaluated using ISSR markers. Beta-glucan extracted by an enzymatic method. Significant differences were found at the level of 1% among barley genotypes for beta-glucan content. The beta glucan content was variable from 7.21 to 12.48 and, the Yosef, E94B3 and E94B17 genotypes hold the highest content of the beta-glucan. ISSR primers with average polymorphism of 66.79%, genetic diversity of 0.25 and Shannon index of 0.37 were determined as efficient markers for studying genetic diversity. The barley lines and cultivars were assigned in two distinct groups according to their genetic pedigree. On the basis of non-parametric Kruskal-Wallis, Spearman correlation, and stepwise regression analysis, nine informative primers were detected explaining highest seed’s beta-glucan content variations ranging from 24.3 to 42.4 percent. The ISSR6 (700), the combination of ISSR1+ISSR4 (1400) and IS2+ ISSR2 (1400) primers were the most informative primers for the beta-glucan content. The informative markers provide possible functional and efficient marker based selection method and, screening the barley germplasms for the highest beta-glucan content.

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.

This study was conducted to evaluate the gene effects, heritability, heterosis and identification of appropriate breeding methods for improving rice viscosity parameters, during 2014-2016 at Rice Research Institute of Iran. The progeny obtained from the North Carolina III mating design with their parents were planted in a randomized complete block design with three replications. Analysis of variance for viscosity parameters revealed that the effect of females, male effect and interaction between males and females effect were significant for all parameters with the exception for peak viscosity. Evaluating of genetic parameters indicated that viscosity characters are affected by additive and non-additive effects of gene action. The share of non-additive effects in genetic control of peak viscosity had beyond additive gene action, while, the contribution of additive effects was greater for the breakdown viscosity, final viscosity and setback viscosity. High estimates of broad sense heritability revealed that the expression of viscosity parameters is more influenced by genetic effects. With regard to non-additive gene actions and low narrow sense heritability estimation in peak viscosity, using hybrid based programs would be promising to improve this trait. For other viscosity parameters, narrow sense heritability estimates were high. Therefore, the use of selection based programs to improve these traits is encouraging. Assessing of relative heterosis through mid-parents showed that heterosis ranged from -3.73 to 1.93%, 5.51 to 21.33%, -4.57 to 1.26% and -26.04 to 9.36%, for the peak viscosity, breakdown viscosity, final viscosity and setback viscosity, respectively.

The production of new and compatible cultivars to different environments is one of the most important goals for the breeders. The crossing new cultivars and the selection of superior genotypes for desirable traits among their offspring is a method that has always been used by breeders. 28 genotypes obtained from the crossing of a 7 × 7 one-way diallel experiment consisting of seven parents (Alvand, Anfarm9, Chamran2, BC Roshan, Qods, Ofogh, local variety Sorkh-dane) and their 21 hybrids were investigated in a randomized complete block design with three replications in the research field of the Faculty of Agriculture of University of Birjand (Iran) under non-stress and drought stress conditions. The analysis of variance showed a significant difference among genotypes for all traits. Mean squares of GCA and SCA were significant for all traits under non-stress and stress conditions, so, there were additive and non-additive components of heritable variance in all traits. The BC Roshan parent had the high combining ability and Ofogh parent had the lowest combining ability in most traits in non-stress and stress conditions. In both conditions, BC-Roshan × Chamran2, Sorkh-dane × Qods and Ofogh × Anfarm9 hybrids had the highest yield and yield dependent traits. Hayman's variance analysis showed that component a (additive genetic diversity), component b (dominance genetic diversity), component b1 (heterosis), component b2 (heterosis specifically for each parent), and component b3 (specific dominance deviation per cross) were significant in both conditions in all traits.The Hayman's analysis confirmed the results of Griffing's analysis.

To investigate the effect of exogenous brassinosteroid application on grain yield, catalase, chlorophyll content, membrane mtability index and gene expression of some genes involving in brassinosteroid signaling pathway (BES1 and BRI1) under drought stress, a split-split plot on randomized complete block design with three replications was conducted at the experimental field of Seed and Plant Improvement Institute, Karaj, Iran in 2019. The main factor was two irrigation treatments (normal irrigation and water holding after 50% flowering stage), the subplots were four concentrations of brassinosteroid (0, 0.25, 0.625 and 1 mg/l) and seven genotypes (Mehregan, Paris, 2858, 3505, 3737, 4228 and 4056) were considered as sub-sub plots. Samples were taken at 30 days after 50% flowering stage (zadoks 89) from flag leaves. The results showed that drought stress significantly reduced grain yield, chlorophyll content, membrane stability index and increased catalase in all genotypes. Genotype 4228 was identified as the most tolerant genotype among unknown wheat genotypes based on grian yield, chlorophyll content, membrane stability index and catalase. Also, the result revealed that applied epibrassinolide could reduce the destructive effects of drought stress on wheat thus grain yield was enhanced under drought stress in all genotypes by increasing the aforementioned traits. Forethermore, grain yield was increased by rising the epibrasinolide concentration. Gene expression pattern of TaBES1 and TaBRI1 using real-time PCR showed that although brassinosteroid enhances drought tolerance in wheat but its signaling pathway is different from the BRI1 signaling pathway.

In order to analyze the genetic components of agronomic traits among 116 F9 recombinant lines derived from crosses of Ahlamitarom × Sepidroud rice cultivars, an experiment was conducted as a randomized complete block design in research farm of Gonbad Kavous University of Agriculture with three replications in 2016 and 2017. Genetic linkage map provided with 80 SSR markers, 28 iPBS Markers (79 polymorphic alleles), 7 IRAP markers (17 polymorphic alleles) and 26 ISSR markers (70 polymorphic alleles), which covered 1275.4 cM of the rice genome. QTL analysis was performed by Composite Interval Mapping. In two years, 15 QTLs detected for the studied traits. The additive effected varied from 6.725 g for grain weight up to -85.626 g for grain weight. Also, R2 for the detected QTLs explained from 11.3% to 20% of the total variation. The highest R2 was related to grain weight in the first year of experiment. Among the detected QTLs, qGWs on chromosome 1, were found to be stable and large effector QTLs for rice (Oryza sativa L.) grain weight, and can be used in marker-assisted breeding and selection programs after validation.

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.