Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2011 | Volume:18 | Issue:2 (36)|Papers Count:14

Agropyron species as important range plant species in Iran are resistant to various environmental stresses. This research was conducted to analyze genetic variation in Agropyron desertorum, Ag. Cristatum, Ag. pectiniforume and Ag. elongatum by RAPD markers. Fifty random primers were used and 12 primers were selected, by which, 142 polymorphic bands with lengths ranged from 200 to 3000 bps. Were obtained. On the basis of Nei's gene index, average genetic diversity within populations varied from 0.09 to 0.30. The largest and the smallest values were obtained in population 1550 (from Ag. cristatum; 0.30) and population 225 (from Ag. elongatum; 0.09), respectively. Results showed high variation within populations. Mean of genetic variation within (HS), Total (HT) and degree of genetic differentiations (GST) were 0.18, 0.34 and 0.47, respectively. Analysis of molecular variance (AMOVA) displayed significant variation within and among Agropyron species and populations. The results showed that only 19.31 present of total variation belong to between species. Between and within populations variations were 22.23 and 58.46 present, respectively. Cluster analysis based on Nei's genetic similarity and UPGMA method, categorized the entries into four clusters. Populations of Ag. Desertorum and Ag. Cristatum grouped in two separate clusters. Populations of Ag. elongatum and Ag. pectiniforme grouped in another cluster and obtained markers could not separate the populations of the two species. One population from Ag. elongatum formed a distinct group. Classifying the populations using principle coordinate analysis (PCoA), verified the results of cluster analysis. Results showed that enough variation exist between and within Agropyron species and populations that can be used in breeding programs of the species.

Several species of Moringa, growing in tropic and sub-tropic regions of Iran, are gaining commercial value for their application in medicine, food industry, and, environmental aspects. Seed storage proteins were extracted from two species of the genus named, M. oleifera and M. peregrina. Protein profile of several plant populations of the species was obtained using SDS-PAGE, in which the protein bands were clearly separated. The bands were scored 0 or 1 for absence or presence of the single bands, respectively. The total distances of the present bands of the profile of each genotype from the beginning point on the gel were summed to get the cumulative distances as a characteristic of each profile. Cluster analysis was performed on the data matrix using JMP software. The dendrogram produced by the software was used to classify the studied genotypes. Remarkable differences were observed between the two species based on the protein profiles, suggesting that the technique can be used to classify the populations of the species. Remarkable variation was observed between the studied samples of the indigenous species, M. peregrina. In other words, the results indicated that the technique is feasible to be used to study genetic variation between the populations of the Moringa species, particularly the indigenous species.

The impact of artificial selection as the critical practice in forest management, thinning and selection of seed trees, on genetic structure was examined in oriental beech (Fagus orientalis Lipsky). In ten beech (Fagus orientalis Lipsky) populations along Hyrcanian forests, genotype of trees compared with 10 selected mother trees and their seeds (each 7 seeds) as next generation, based on four highly polymorphic microsatellite loci. In two populations forked and monopodial trees and their seeds were also investigated to study phenotypically based tree selection in forest management. Significant differences were found for allelic richness (Na), effective number of alleles (Ne), number of rare alleles, either for observed (Ho) or expected heterozygosity (He) between trees and seed samples in each population. Because of an association between the occurrence of rare alleles and tree phenotypes, phenotypically based tree removals were associated with a shift in allelic frequency and number of rare alleles, which followed by decreasing future genetic potential. Because of the theoretical long-term evolutionary benefit of unique gene forms, the loss of rare alleles could diminish the potential of populations to adapt to and survive ongoing environmental change. The results indicated that intense selection or thinning might severely affect genetic structure of beech population in long term, confirming efficiency of sustainable stand management policies with emphasis on the close to nature silviculture system and the employment of un-even aged form methods. As beech populations seem not to be affected by single or partial thinning activities, the selection system (both, the single and the group selection system) is a suitable silvicultural system for the Caspian beech forests.

To evaluate the effects of induced mutation by Ethyle Methane Sulphonat (EMS) on general combining ability (GCA) and character relationships on Sainfoin, 40 M3 genotypes along with 39 non-mutant counterpart genotypes were assessed for 18 agro-morphological traits in the field during two years. Means comparison by year showed that mutant genotypes were superior for leaf/stem ratio and dry matter yield after established in the second year. Results showed that general combing ability (GCA) was lower in mutant genotypes for most of the traits. However, for several traits such as leaf to stem ratio the parameter was higher in mutant families. Cluster analysis based on general combining ability grouped mutant and non-mutant families separately in three clusters. Based on important traits, a number of mutant (8, 10, 12, 20, 25, 26 and 36) and non-mutant genotypes (7, 8, 9, 10, 11 and 12) were selected as best parents for synthetic variety development. Mutation changed relationships between several characters. For example correlation of dry forage yield with number of inflorescence was negative in non-mutant while positive in mutant families. Correlation of leaf percentage with number of stem per plant was positive in mutant but negative in non-mutant families. Factor analysis also showed that mutant families with fewer factors explained greater variance than non-mutant families, indicating that mutation induction and selection can change combining ability and relationships of traits and factors affecting the relations.

This study was carried out to evaluate morphological and drought tolerance indices based on mean yield of 18 Agropyron elongatum accessions. Experiments were set up based on the randomized complete block design (RCBD) with three replications, in two environments (stress) and irrigated (non-stress) conditions. There was significant differences (p<0.05) between plant height and number of tillers. The tallest height with 123.09 cm belonged to accession 17 and the shortest height with 112.8 cm belonged to accession 14. The number of tiller ranged from 105.6 to 54.61 for genotype No.1 and No.13, respectively. Forage had significant (p<0.01) positive correlation with plant height (0.657) and tiller numbers (0.797). Last node distance had negative correlation with forage yield (-0.236), dry matter (-0.415), flag leaf length (-313) and number of tiller (-0.121). There was significant positive correlation (p<0.01) among mean productivity, harmonic mean and geometric mean productivity indices in stress and non-stress conditions. Based on Fernandez, model; genotypes 10, 14 and 15 as superior were located in A group. Coefficient of variation ranged from 5.91% to 29.1%. In these experiments on the based of all traits studied, the accessions number 1, 3, 8 and 9 were superior and the accessions number 13 and 14 showed weakest performance.

Determining genetic diversity of plant materials is necessary in the beginning of any breeding program. In this study, genetic diversity within and among 15 orchardgrass ecotypes collected from different parts of Iran, 7 foreign ecotypes (USA, Russia, Stonia, Spain) and  3 ecotypes with unknown origin were evaluated using RAPD markers. Eight primers from 40 tested RAPD primers produced 73 polymorphic bands. The total number of polymorphic bands within ecotypes varied from 25 to 49 bands. The averages of total and within ecotypes genetic diversity and the degree of genetic differentiation were estimated 0.291, 0.181 and 0.378, respectively. Molecular variance analysis based on squared Euclidean distances indicates that larger proportions of variability existed within ecotypes (78.37 %). Cluster analysis of molecular data, grouped the entries under study into 8 cluster. The grouping based on molecular data had not correspondence with the geographical pattern. Using principal coordinate analysis, the first tree coordinates determined 59.48% of the total variation. Grouping of ecotypes using the first two coordinates confirmed the results of cluster analysis. Cluster analysis of morphological data, grouped the entries into 4 cluster, but great match between the results of morphological and molecular data weren’t observed. In this study, a great amount of genetic diversity observed between and within orchardgrass ecotypes that could be used for selection suitable varieties and the ecotypes with exceeding genetic distance could be used in crossing programs for producing heterosis, mapping populations and disperse generations.

English yew (Taxus baccata L.) species is one of the rare native conifers of Iran and remained from tertiary third growth period. Due to excessive exploitation and also for slow growing, now a days the species is facing extinction treat and remaining individuals have high genetic value. Genetic diversity existence between populations of one species display the best ways for diversity conservation of the populations and for finding plus maternal individuals for seed stores. This research was done with the aim of evaluation and comparison of genetic diversity and polymorphism of yew, based on branch and leaf peroxidase, verifying best organ for genetic diversity study and for recognition of index individuals of yew in Afratakhte location of Zarin Gol in Aliabad of Golestan province (IRAN). Contemporaneous sampling from biennial growth of branch and leaf of 42 individuals were taken based on three populations. Extracts were prepared from the samples immediately after the sampling. Measurements of quantitative activities were done by spectrophotometer and qualitative studies with electrophoresis by PAGE (polyacrylamide gel electrophoresis) method. Results showed that yew trees have rather well genetic variation in Afratakhte location. For quantitative activity, significant differences were observed between branch and leaf organs at 95% level of probability, so that enzyme activity in branch (0.066) was more than that of leaf (0.020). Also the number of branch isoenzymatical bands (12 bands) was more than that of leaf (6 bands). Results of cluster analysis also showed more grouping in branch (12 groups) than leaf (8 groups). Therefore, branch organ, comparing with leaf organ has higher ability for separation and grouping in considering of genetic diversity of yew trees.

The study was carried out on karyotypes of 15 Panicum miliaceum L. and Setaria italica L. populations. Karyotypic attributes were recorded at metaphase stage of mitotic cells of the populations. Karyotypic parameters, including total length of chromosome, long and short arms length, arm ratio, centromer index, differences between the relative length, intra and inter-chromosomal index and total form percentage were estimated. Analysis of variance using completely randomized design model showed a significant difference (P<%1) among the populations for all of the estimated parameters. Total length of chromosomes varied from 87.3 micrometer in population of Najaf Abad to 238.3 micrometer in population of Badroud. The chromosome number was x = 9 for studied populations. P. miliaceum and S. italica were tetraploid and diploid, respectively. According to Stebbins classification, most of the populations placed in 1A and 2B class, indicating relative symmetrical karyotype.

Objectives of the study were to assess general combining ability on fifty genotypes of tall fescue. During 2006, the genotypes were sown in the nursery polycross. Polycross seeds were sown based ob a randomized complete block design with 3 replications to evaluate general combining ability of several traits in tall fescue during 2007. Analysis of variance showed significant differences among the genotypes for most of the studied traits. The highest coefficients of variation were obtained for forage dry yield, forage fresh yield, number of stems and rust resistance. Least coefficients of variation were obtained for crown diameter per plant, plant height and peduncle length. Broad-sense heritability was very high for forage dry yield, forage fresh yield, number of stems, crown diameter per plant and plant height. Genetic advance was optimistic for dry yield, forage fresh yield and number of stems. Cluster analysis classified the genotypes into three groupes. Using principal components analysis, the first three components determined 78/80% of the total variance. GCA for trait forage dry yield, forage fresh yield, number of stems, crown diameter per plant were the most important traits in the first component. The highest values were observed for GCA on 9 genotypes for forage dry yield and forage fresh yield, 10 genotypes for crown diameter per plant, 5 genotypes for plant height and 5 genotypes for peduncle length. Thus, selecting genotypes for the characters must be effective in achieving suitable parent for producing synthetic variety.

The effects of salinity stress were investigated on germination components of Salsola abarghuensis, S. arbuscula and S. yazdiana. The experiment was carried out based on completely randomized design with 5 replicates and 6 salinity levels of 0, 200, 300, 500, 800 mM/L NaCl and NaCl + Na2SO4 (in 70% and 30% ratios). Results showed that germination rate and germination percentage decreased in all the species with increasing salinity concentration (in both salt treatments). For all the species the highest germination percentage was observed on control and 200 mM and the lowest was observed on 800 mM NaCl +Na2SO4. The effects of salinity on root and shoot length were the same as their effects on seed germination. Compared to the other species, S. abarghuensis showed the highest germination on control and 200 mM (94 and 89 percent) and the lowest rate was observed on S. yazdiana (52.4 and 48.5 percent). In turn, S. arbuscula showed the highest germination on 800 mM of the two salt treatments. Chemical analysis of shoots in three mature species showed that S. abarghuensis accumulated the highest amounts of potassium and sodium. The relationship between ion accumulation in plants and soil with salinity resistance is discussed.

In order to study the genetic variability of two Bromus species, B. tomentellus and B. persicus, based on morphological traits, 12 populations were examined in a field experiment using a randomized complete block design with 3 replications during 2006-2008 in Karaj, Iran. The data were collected for heading date, plant height, tiller number, panicle length, seed weight and seed number per panicle, forage dry matter yield, seed yield, thousand grain weight and harvest index. Results showed that B. persicus populations had higher values than B. tomentellus for all the traits except for thousand grain weight. Population 68 of B. persicus with average values of 7157 and 1059 Kg/ha showed higher forage and seed production, respectively. Phenotypic correlation between forage and seed yield was positive and significant. Both traits positively correlated with heading date, plant height and tiller number and negatively correlated with thousand grain weight. Using cluster analysis (Ward method) and principle components analysis (PCA) based on the morphological data, the populations were classified into two groups coordinating to the two species. The distribution of the populations based on (PCA) analysis was in agreement with cluster analysis results.

Lolium is an important genus because of its rapid growth, palatability, high yield potential, cold resistance, and ground covering during cold seasons. The research was carried out to study genetic variation and relationship between the traits on six populations of three Lolium species during 2003. Morphological traits such as tiller number, leaf length, leaf width, stem length and dry matter yield were measured from 4 single plants on each experimental plot. The data were analyzed using RCBD with three replications. Correlation coefficients were estimated between all paired combinations of the traits. Path coefficient analysis was also applied on the morphological traits. Results revealed significant variation among the populations for the traits. Genetic correlation coefficient between dry matter yield and tiller number was significant. Path coefficient analysis revealed that stem length had the highest direct effect on dry matter yield. Leaf length had high direct effect and non significant genetic correlation with tiller number and leaf width. Therefore, leaf length is a good selection criterion to be used for improving Lolium cultivars with higher dry matter yield.

Presenca of diversity in the crop genetic resources including forage crops is necessary for sustainable agriculture. To introduce superior germplasms of new clover species to use in the agronomic system this project was performed. A total of 108 accessions belong to 13 clover species were sown in a field experiment in September, 2007. A selection of 30 accessions from 10 species were sown in the second year (September, 2008). One-way ANOVA showed significant differences among the accessions as well as the species for agronomic traits. Grouping of Duncan analysis for the species and accessions were performed for each agronomic trait. Multiple regression analysis explained 72% of variation for stem length at flowering explained by growth habit, leaf stem ratio, and days to ripening traits. Based on the analysis of variance, and Duncan analysis results, T. echinatum, T. purpureum, T. diffusum, T. hirtum, and T. lappaceum  in descending order of forage yield  can be used in the agronomic systems of Iran as new species. Accessions: 50TN00708, 50TN00822, 50TN00592, 50TN01444, and 50TN01586 of T. echinatum, T. purpureum, and T. diffusum species proposed as high potential accessions after Persian clover. Seed of selected species were regenerated in the isolated system and seed of superior accessions multiplicated for the future experiments.

Priming is highly used for germination improvment of seeds under environmental stress. The research was conducted to study the effect of NaCl priming and hydropriming on germination and early growth of Festuca arundinacea and Festuca ovina seeds under salinity stress. First factor was plant species, the second was pre-treatment priming (NaCl priming with three concenterations, 15, 30 and 45 dS/m at 24 hours, hydropriming at 24 hours and control). The third factor was salinity stress of zero, 5, 10, 15 and 20 dS/m at germination stage. In all priming treatments, germination percent, at high salinity (10-20 dS/m) and the attributes recorded at different salinity level in Festuca arundinacea showed significant differences with Festuca ovina. Priming caused reduction on mean germination time and germination percent, root length, shoot length and vigor index on both species, compared to the control. Generally, considering different attributes recorded on Festuca arundinacea the seeds under NaCl priming with concentrations of 15 and 45 dS/m and in Festuca ovina under NaCl priming with concentration 45 dS/m had the highest performance among the treatments. Generally, seed priming particularly NaCl priming, as a physiologic treatment improved seed performance of both species at germination and early growth stages under salinity stress.