مجله پژوهش های ژنتیک گیاهی
سال هفتم شماره 2 (پاییز و زمستان 1399)

The diallel mating design is an important tool used by plant breeding programs to obtain information on trait inheritance. Knowledge of gene action, heritability and genetic advance from selection is a prerequisite for starting a breeding program for developing varieties of maize. Five maize S7 lines and their F2 progenies were studied in a 5 × 5 half-diallel crossing design to evaluate the gene action and the heritability of biochemical and physiological traits. Parents and their F2 hybrids were planted in a randomized complete block design with three replications at the Research Farm of Graduate University of Advanced Technology (Kerman, Iran) in 2017 cropping year, and chlorophyll (Chl), proline, protein, carotenoid and reducing sugars traits were evaluated. Analysis of variance showed significant differences among genotypes for the studied traits at 1% probability level. The graphical results of Haymanchr('39')s analysis showed the role of over-dominance genes effects in controlling proline content, sugars content, Chl a, Chl b, total Chl and carotenoids traits whiles the protein content trait was controlled by the incomplete dominance of genes. The narrow-sense heritability for carotenoid and proline content traits were 0.14, for protein content was 0.44 and for other traits were varaied in this range. The results of this study showed that the use of heterozygosity and the production of hybrid varieties can be used to breeding traits such as proline content, sugars content, Chl a, Chl b, total Chl and carotenoids. However, for breeding of protein content, use of both methods (selection and production of hybrid) are proposed.

In breeding programs, it is necessary having knowledge of the relatedness and genetic diversity in germplasm pools. The spread of cultivated regions and the high levels of production indicates citrus importance in the global economy. Therefore, 110 citrus genotypes were evaluated using 12 ISSR markers. Overall, 154 polymorphic bands were scored with an average of 12.8 alleles per primer. The polymorphism percentage ranged from 57 for the ISSR1 to 82 for the ISSR9. Averages of polymorphic information content (PIC), marker index (MI), gene diversity index (Nei), Shannon index (I) and number of effective alleles (Ne) were 0.48 ± 0.002, 6.14 ± 1.17, 0.42 ± 0.11, 0.61 ± 0.12 and 1.78 ± 0.27, respectively. Based on genetic diversity statistics, the studied population had high genetic diversity, and four markers (ISSR11, ISSR9, ISSR4, and ISSR5) had more potential for differentiation of genotypes. Cluster analysis and model-based structure analysis, divided the genotypes into five groups and four subpopulations based on the Neighbor-Joining method (NJ) and Bayesian approach, respectively. Based on both analyses, grouping of unknown genotypes and control cultivars in the same group probably confirms the assumption of a common genetic background between these genotypes. Results from the two analyses showed that Pummelo (C. maxima), Mandarin (C. reticulate), and Citron (C. medica), as three true citrus species, separated in different groups. In addition to the three true species, at least one species or another genus of citrus relatives is involved in the genetic makeup of the studied population. In this study, although both used analyses were effective in completing each otherchr('39')s information, by considering the degree of genetic mixing and the information of the origin of the genotypes, the effectiveness of model-based structure analysis in evaluating genetic relationships could be achieved.

There are different methods for study the genotype × environment interactions and determining stable genotypes such as parametric, non-parametric and multivariate methods. In this research, 19 selective genotypes from advanced trials of durum wheat at 2011-2012 agronomic year, have been cultivated with Dehdasht check cultivar for three growing years (2012-2015) in five locations (including Gachsaran, Gonbad, Khorramabad, Moghan and Ilam) in a randomized complete block design with four replications in each location. Combined analysis of variance indicated significant effects of genotype, environment and interactions of genotype × environment. In parametric uni-variate methods, genotypes 7, 12, 18 and 20 were determined as stable genotypes. In non-parametric uni-variate methods, genotypes 2, 7, 12, 13, 18, 19 and 20 had the lowest genotype × environment interaction and they were determined as stable genotypes. In AMMI method, genotypes 2, 7, 12, 19 and 20 had the lowest rank in different environments and highest grain yield, and these genotypes seems more stable genotypes. It can be concluded that genotypes 7, 12, 18 and 20 could be considered as promising genotypes and candidate for introducing new durum cultivar.

In oilseed crops, a number of genes involved in the production of triacylglycerol have been identified that changes in their expression have increase the seed oil content. WRI1 and LPAAT are key genes in this synthetic pathway that their overexpression can increase the oil content. In this study, the expression vectors carrying WRI1 and LPAAT genes were designed and constructed for genetic transformation of tobacco (Nicotiana tabaccum) plants. The synthetic WRI1 and LPAAT genes were isolated from the PGH.WRI1 and PGH.LPAAT cloning vector using specific restriction enzymes and then cloned in the PGH.O3.2.2 intermediate vector under the control of SBP and Napin promoters and E9 terminator. Finally, the genetic cassettes were transferred to the plant transformation pBin19 binary vector. The resulting constructs were transferred to Agrobacterium tumefacience strain EHA105 and were used for genetic transformation of tobacco plants. Molecular analysis of transgenic plants confirmed the presence and activity of WRI1 and LPAAT genes. Seeds from transgenic plants were selected on the medium containing kanamycin and developed strong and healthy seedlings.

In order to identify QTLs controlling agronomically traits, landrace Tarom and rice Tarom mutant were crossed. SSR, ISSR, iPBS and IRAP markers were amplified in 250 F2 individuals to prepare the linkage map. Number of tillers, 100 grain weight, number of filled grains, number of unfilled grains, plant height, panicle length, number of branches, stem diameter, grain length, grain width, grain shape, straw weight, days to maturity, flag leaf length and flag leaf width were measured for 250 individuals. The linkage map covered 970.9 cM of rice genome. The distance between two adjacent markers was calculated to be 12.77 cM. Based on the results, a total of 13 QTLs were identified for the evaluated traits. For all studied traits, alleles transferred from the parents to the QTLs detected increased grain yield. Most QTLs were detected for days to flowering. Three QTLs were located on chromosomes 10 and 4 (two QTLs) for days to flowering. qLDF-4a and qLDF-4b had a negative additive effect and the parent alleles of the mutant landrace Tarom reduced the number of days to flowering. These QTLs explained 11.6% of the phenotypic variance. Since the population under study was derived from a cross between landrace and mutant Tarom cultivars and the resulting population varied only in the mutated genes; so, the QTLs detected in this study were more accurate in location and expression levels, and after validation of them, they could be recommended for marker assistant selection breeding programs.

The genotype × environment interaction is a major challenge in the study of quantitative characters because it reduces yield stability in different environments and also it complicates the interpretation of genetic experiments and makes predictions difficult. In this regard to analysis of genotype × environment interaction and determine the yield stability of winter rapeseed genotypes in cold and mild cold regions of the country, 9 lines and 4 cultivars were evaluated in a randomized complete block design with three replications in six experimental field stations (Isfahan, Hamedan, Karaj, Kermanshah, Khoy and Zarghan) during 2015–2017 growing seasons. Results of combined analysis of variance indicated that the effects of environments, genotypes and genotype × environment interaction were significant, suggesting that the genotypes responded differently in the studied environment conditions. So, there was the possibility of stability analysis. The Nafis cultivar and BAL-92-1 line with seed yields 4086 and 3829 kg.h-1, respectively, were better than overall mean and had lower ranks and rank variance than others. According to the results of stability analysis using Eberhart and Russel method, the BAL-92-1 line with higher seed yield than overall mean and regression coefficient equal one (bi=1) was identified as the genotype with high general stability for all regions. Based on the simultaneous selection method for yield and stability (YSi), the lines of HW-92-1, BAL-92-1, HW-92-1 and Nafis cultivar with the lowest values were stable, whereas lines BAL-92-4, HW-92-2, HW-92-3 and Ahmadi cultivar with highest values were unstable. Also, based on the SIIG index, the lines of HW-92-1, BAL-92-1, BAL-92-6, BAL-92-11 and Nafis cultivar with having high SIIG value as well as higher seed yield that total average were recognized as superior genotypes from the point of stability and seed yield. Finally, BAL-92-1 line with high yield and broad adaptability was selected as superior line for supplementary studies to introduce the new commercial cultivar in cold and mild cold regions of Iran.

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.

Cultivar identification in micro-propagated date palm seedlings is laborious so that application of molecular markers to facilitate and acceleration of the procedure seems inevitable. Given the need for control the originality of micro- propagated date palm seedlings, the aim of this study was evaluation of SSR markers usability to cultivar identification in micro-propagated date palm seedlings. Original samples of Green Ghanami, Red Ghanami, Gantar, Deiry, Ostaemran, Barhi, Medjool, Zahedi and Piarum cultivars were used control. Taking into account the rigidity of leaves and subsequently high consumption of liquid nitrogen to powder leaves, an efficient method for powdering of leaves using Tissue Lyser II instrument was optimized. Eight SSR primer pairs were used for polymerase chain reaction. The Results showed that by using these molecular markers and reliable controls, determination of micro- propagated date palm cultivars is feasible. Clustering of cultivars showed that all of them were differentiated using five SSR primer pairs including mPdCIR025, mPdCIR057, mPdCIR070, PDAG1003 and DP175. Also, barcoding of scored band illustrated that c1 allele (230 to 240 bp) for Piarum cultivar and d3 allele (220 to 230 bp) for Medjool cultivar were exclusive. Totally to make the results referable, cultivar identification diagram was drawn up.

Sweet flag (Acorus calamus) is a perennial, semi-aquatic and aromatic plant of the family Acoraceae that, in addition to its multiple medicinal properties, is used in health, food and agricultural industries (as pest control). This research was conducted to comparasion study of genetic diversity of natural and regenerated plants from tissue culture of Arzefon, Pelesk and Alandan populations of Sweet flag by using ISSR molecular markers. Out of 15 screened primers, 9 primers produced the most polymorphic bands. Totally, these primers generated 83 bands, of which 52 bands (62.65%) were polymorphic. The percentage of polymorphic locus for natural and regenerated plants was 43.37% and 55.42%, respectively, and Nei’s genetic diversity (H) was calculated to be 0.239 for the two studied groups. The Shannon’s index (I) for natural and regenerated plants was estimated to be 0.251 ± 0.033 and 0.299 ± 0.031, respectively. Among the natural and regenerated groups, the highest genetic similarity was observed between the samples of Alandan population (0.63), and the lowest value was observed between the samples of Pelesk population (0.44). Analysis of molecular variance (AMOVA) showed that 94 % of genetic variation attributed to whithin groups and 6 % to between groups. Based on the results, the genetic diversity of the regenerated plants was higher than the natural plants. According to the results of the present research, the lowest rate of genetic divergence was observed between natural and regenerated plants of Alandan populatiuon, so the plants of this population could be suitable for domestication and cultivation in Iran.

Optimization of in vitro methods for the production of maize double haploids plays an important role in the breeding programs of this plant. In this study, the effects of 5-azacytidine on agronomic traits, androgenesis induction efficiency and also, DNA methyltransferase gene expression (AF229183.1) in two growth stages of maize were investigated. This experiment was performed as factorial based on a completely randomized block design with three replications. Two maize genotypes (DH5 × DH7 and ETMH-82) were considered as the first factor and treatment of maize seeds with 5-azacytidine (0, 5, 10, and 100 μM) was considered as the second factor. The maize seeds were sowed in the field and during the growth stages, various morphological and agronomic traits were recorded. In the anther culture experiment, the suitable anthers containing microspores at mid to late-uninucleate stages were selected and cultured in an YPm culture medium containing 1 mg/l 2, 4-D, and 2 mg/l BAP. Interaction effects of genotype and 5-azacytidine concentrations showed significant differences for the majority of studied traits except for number of kernel per ear row, kernel depth, plant diameter, number of leaves and number of ears. The highest amounts of 1000-kernel weight were obtained with treatments of 10 and 100 μM and the highest ones for grain yield and biological yield traits were obtained with 100 μM 5-azacytidine treatment for both genotypes. Seeds of DH5 × DH7 genotype treated with 5 μM 5-azacYtidine produced the highest mean number of embryo-like structures (0.1833) and regenerated plantlets (0.067) per each anther. Relative expression of DNA methyltransferase gene in maize seeds treated with different concentrations of 5-azacytidine showed a significant decrease in both genotypes and both growth stages compared to control plants (treated with 0 μM 5-azacytidine), that this decrease in gene expression could lead to improved androgenesis induction in anther culture of DH5 × DH7 genotype. However, despite the decrease in expression of this gene in two growth stages of ETMH-82 genotype, androgenesis induction was not observed in this genotype. The results of the present study can help to determine the role of epigenetic factors in androgenesis induction and improving the production of haploid plants in maize.

Under drought stress condition, the signaling system induces expression of certain genes to counteract the deleterious effects of environmental stress. Among the essential micronutrients for plant growth and development, zinc has an important role in many plant metabolic processes including gene expression and stress tolerance. In order to investigate the effect of drought stress and ZnO on relative expression pattern of some genes involved in abiotic stresses (including WRKY1, HMA2 and ZIP1 genes) in wheat cultivars, a factorial experimental was conducted in pot condition based on a completely randomized design with three replications. In this experiment, the first factor was three levels of drought stress (35, 60 and 85% of field capacity), the second factor was three wheat cultivars (including Heidari, Meihan and Sysons), and the third factor was three levels of ZnO (0, 0.5 and 1 g/l-1). According to the results, with increasing the level of drought stress, the relative expression of WRKY1 and ZIP1 genes in drought tolerant cultivar (Meihan), and also with increasing nanoparticle concentration over stress time, the expression of ZIP1 gene in drought sensitive cultivar (Sysons) increased. The highest relative expression of HMA2 gene was observed in Heidari cultivar under mild drought stress. Generally, the expression of all three genes studied in tolerant cultivar (Meihan) increased under drought stress. Increasing the expression level of HMA2 and ZIP1 genes could be related to the transfer of zinc to consuming tissues and also, to increase the consumption of zinc in current metabolism of plant, which is important in tolerance of wheat to drought stress.

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.

Additive main effect and multiplicative interaction (AMMI) and best linear unbiased prediction (BLUP) are two methods for analyzing multi-environment trials (MET). In this study, seven selected rice lines were evaluated along with two check varieties based on randomized complete block design in Tonekabon, Amol and Sari (Iran) in three growing seasons of 2011-14. To quantify the genotypic stability, the best linear unbiased predictions of the genotype by environment interactions (GEI) were estimated, and singular value decomposition (SVD), which is the basis of AMMI analysis, was performed on the resulting matrix. The likelihood ratio test (LRT) showed that the effect of GEI was significant on grain yield, number of tillers, thousand grains weight and panicle length. Therefore, due to the significant interaction of genotype by environment, BLUP analysis can be performed on this data. The biplot of first principal component (PC1) of the environment versus nominal yield showed that genotypes 7 ([IR 67015-22-6-2-(A37632) × (Amol3 × Ramzanalitarom)]39), 6 (IR67015-22-6-2-(A37632) × (Amol3 × Ramzanalitarom)]126) and 2 ([IR64669-153-2-3 - (A8948) × (4Surinam Deylamani)]2), due to the lowest scores of the PC1, had a small share in the GEI and had more grain yield stability. The biplot of grain yield versus WAASB, placed genotypes in four regions, so that genotypes in the fourth region, including genotypes 6, 7, 8 (Line 843, check variety), and 9 (Shirodi, check variety), were due to large value of response variable (high grain yield) and high stability (low values of WAASB) were very productive and had extensive stability. Identification of genotypes with weighted average of WAASB and response variable (WAASBY) criteria showed that genotypes 6 and 7 were high yields and stable. Based on the multi-trait stability index (MTSI), G6 was also selected as the best genotype in terms of grain yield, evaluated traits and stability of each trait. Totally, genotype 6 was stable and superior based on the results of all methods.