Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2003 | Volume:11 | Issue:1|Papers Count:12

Thuja orientalis is an important forest tree species for timber and wood production. Its wood is light in weight and highly resistant to decay. Regarding difficulties in conventional propagation of Conifers, specifically hard rooting f cutting in adult trees this study was carried out For investigation of asexual regeneration in Thuja orientalis apical buds from adult trees and seedlings were collected in 3 seasons. After presterilization, the best method for sterilizing of buds was identified. The method was: Cleaning and brushing the buds between and ethanol 70% solution as the pretreatment, dipping them in ethanole 70% for 1minutes and cleaning buds with 0.1% HgCl2 solution in different periods (4 for spring, 6 for summer, and 9 minutes for fall). The suitable medium for establishment was DKW medium with 0.5 mg/lit 2iP. Established explants were subculture in 3 media (MS, DKW and SH) containing 2iP and BA alone or in combination (from 0 to 0.5 mg/lit) + IBA (0.01 mg/lit). After two sub culturing of buds in the media, the means of shoot proliferation and shoot length growth was used as the data for analysis of variance. The best medium for shoot regeneration was the DKW with 0.5 mg/lit 2iP, 0.01 mg/lit IBA (83%). Rhyzogenese of shoots was done in DKW medium supplemented with 2 mg/lit IBA (33%).

Salad burnet has a lot of importance from different points of views, such as medicinal and forage purpose. This research was carried out to estimate the salinity resistance of salad burnet at seed germination stage. Five NaCl Levels 0, 50, 100, 150 and 200 mM treatments were used in five replication in a Complete Randomized Design experiment. Seed germination percentage was increased by increasing of NaCl concentration upto 150 mM, however decreased at 200 mM NaCl. It means appropriate salt concentration, is necessary for seed germination. By increasing salt concentration the radicle length and plumule length decreased.Analysis of variance of data showed that effects of different salinity treatments on percent of germination, radicle lengh and plumule length characters were statistically significant and characters of radicle length and plumule length had a linear trend, whereas, percent of germination had squared trend. The correlation coefficient between any two characters of radical and plumule length and percent of germination was positive and significant.

Peroxidase is an indicator enzyme for temperature stress in plant species. The chilling temperature showed increasing rate of peroxidase in annual Medics. Peroxidase has an important role in biochemistry and polymerization (e.g. Lignification) in plant species.This work was carried out to show the effects of different temperatures 0, 5, 10, 15, 20°C and green-house conditions on the level of peroxidase enzyme in annual medics. Nine genotypes from six spices of annual medic were established in an aquaculture system at 20°C for 35 days in a growth-chamber. They were planted in Hogland solution. After 44 days, temperature treatments in a split plot experimental design, the amount of peroxidase of plant shoots were measured.There was a signifucaut difference of peroxidase level between 0 and 5°C and the other temperature treatments (10, 15, 20°C and green house). Therefore, when the environmental temperature decreased the level of peroxidase would increase in annual medic's shoots. The level of peroxidase as well as peroxidase behavior in relation with temperature treatments varied in different annual medic species.

In this study, drought tolerance in Rosa damascena from different parts of Iran was analyzed in Research Institute of Forests and Rangelands in 1991. Growth pattern of stem cuttings of 30 genotypes were evaluated in recovery environment, after a 21 day water stress, by multivariate analyses. The scored characters were plant survival, branch number, leaf number, leaflet number, leaflet area, longest branch, and plant vigor. The statistical multivariate methods applied included multivariate linear regression, path analysis, principal components analysis (PCA) and cluster analysis. According to the results of regression analysis, plant vigor, leaflet number, and leaflet area showed a significant association with survival, and a good fit was obtained for this association by linear regression model. Path analysis revealed that the greatest direct effect on plant survival being positive was related to leaflet number, and the lowest direct effect which was negative, was related to the leaflet area. The direct effect of plant vigor on survival was negative, but relatively high. Also, indirect effects of plant vigor via leaflet number and leaflet area were positive and negative, respectively. Leaflet number is therefore the most important trait and it could be possible to increase drought tolerance of Rosa damascena by selection for this variable. Principal components analysis (PCA) presented three components indicating more than 82% of the total variation. The highest special values belonged to second component, based on which genotype 88B was selected for survival percentage under drought stress. Cluster analysis classified the genotypes in seven, groups, based on the traits under study. The obtained result therefore, indicated that the highest variation could be achieved for the traits under study, through combining genotypes in the first and seventh groups.

Bromus is one of the most important genus in the rangelands of which several species have covered a vast areas of our country. Different species of the genus have not been paid enough attention for genetic and cytogenetic variation whereas, information on karyotypic characteristics and ploidy levels are of primary requirements of breeding projects of each plant species. For these reasons in the current study several species of Bromus were studied for karyotypic characteristics by studying metaphase chromosomes in mitotic meristem cells. In order to prepare mitotic cells, fresh grown root tip meristems of germinated seeds were used. Bromonaphtaline, Farmer fixative and Hematoxiline were used for pretreatment, fixation and staining, respectively. Six species of the genus were studied in this research. Different ploidy levels were observed between the different populations and species, which were mainly a multiplication of seven. This variation in ploidy level particularly within the species could cause morphological variation and resultantly better stability of the species. It could also provide the suitable opportunity for utilizing the variation in breeding and developing Bromus cultivars in the country. In the future studies the populations have to be studied for karyotype asymmetry to find relationship between the populations in order to use their potentials in breeding projects.

In order to evaluate dry matter yield and morphologic traits of 18 foreign and domestic ecotypes/varieties alfalfa (Medicago sativa), were planted in Alborz Research Center, Karaj, Iran. These ecotypes/varieties were evaluated under optimum and drought stress conditions using complete block design with three replications during 1999-2001. The data were collected and analyzed for forage dry matter yield, flowering date, summer growth score, winter growth score, stem density, plant height, leaf/stem ratio, insect resistance (Hyper postica Gyll), crude protein percent and crude fiber percent for mean of each year and combined over two years.The results showed significant differences among ecotypes/varieties for, flowering date, summer growth score, crude protein and crude fiber percent in first year and for plant height, leaf/stem ratio and dry matter yield in the second year under optimum condition. In drought stress, the results showed significant differences for plant height (first year) and crude protein and summer growth score (second year). In combined analysis over two years, the effect of year was significant for all traits in both experiments. The genotype x year interaction effects was significant only for plant height and crude fiber under optimum condition. For flowering date Yazdi and Cankreep, were the earliest and Maraghah and Harati were the latest varieties under optomum condition. For plant height, Sent Luis1009, USA2564 and Hamadani under optomum and Hamadani, FA02436 and hunter-river under drought stress had the higher plant height. For leaf/stem ratio Maraghah and US-2564 had the highest values under optomum and drought stress, respectively.For annual dry matter yield, Hamadani and FAO-2435, with an average of 7 tonlhe/year and Simerchenskaia, FAO-2435 and Nomad with 1.5 ton/he/year had the higher forage production under optimum and drought stress conditions, respectively.In general, Hamadani, Harati, FA02433, FA02436 were suggested for cultivating under optimum condition and Hamadani, Gharah Youngeh, Hunterriver, Sent Luis1529 and Numad were suggested for dryland farming system. However, Gharah Youngeh had better quality than Hamadani.Phenotypic correlations between traits were consistent over two conditions. Plant height and dry matter yield were negatively correlated with crude protein and positively correlated with fiber content. Plant height was positively correlated with winter growth and negatively with flowering date. Summer growth score was positively correlated with both dry matte yield and winter growth score. Leaf/stem ratio was positively correlated with crude protein and negatively with plant density and plant height.

In order to examine and evaluate the variation and process of deterioration of accessions of Festuca ovina seeds, which have been collected in natural resources genebank, research programs were carried out using 11 accessions. All of the accessions were examined in a complete randomized design with three replications under two different conditions, germinator and glasshouse. The recorded traits of the Germinator test included, seed viability, speed of germination and vigor index. The recorded traits of the test in glasshous, included germination persentage (G.P.), speed of germination, plant height, number of tillers and root length in 40 days after planting.Significant differences found between accessions for all of the studied traits. Variation between accessions was significant in one or both of the environments. The results of correlation coefficient study had shown that negative correlation was found between reduction of seed viability, speed of germination and seed vigor in germinator condition and G.P. and speed of germination in glasshouse condition.Therefore, seed deterioration not only reduces seed viability and G.P, but also decreases the speed of germination and seed vigor.In all of the Festuca ovina accessions, because stored samples of each year were different from other years, therefore reduction of seed viability, was highly affected by origin of accessions. It was not possible to differentiate between the effect of maintaining condition and origin of seed. It was suggested that, for better genebank management, accessions, have to be considered as regeneration unites of collected seeds.

Trigonella genus of Papilionaceae family according to Flora of Iranica has 32 species in Iran. It is a medicinal, range and cultivated plant with many uses in the traditional medicine and as a forage crop.In this study eight species of Trigonella were collected and identified from Fars Province. Results showed that T elliptica was found to be perennial and T foenumgraecum, T spruneriana, T monspeliaca, T uncata, T anguina, T stellata and T astroites were annual. All of them were diploid with 2n=2x=16. Genomic analysis including, the length of each chromosome, long and short arm ratio ect. determined and their ideograms drew. This study showed that all of the species have the metacentria and submetacentric chromosomes and T foenum-graecum with 26.28 micrometer and T stellata with 13.52 micrometer total length of chromosome have the longest and the shortest genetic material respectively.To find the relationship between the species, chromosome characteristics were analysed using SPSS software and group relationship was shown on a dendrogram.

Reference to the International Seed Testing Association, seed health testing is the most important aspect of seed testing. The seed borne fungi and insects cause reduction of viability and vigor of the seed samples. Therefore, seed health test should be considered in seed testing. In this research, seed samples of some species collected from different regions of Iran, were chosen for seed health testing. After cleaning and determination of physical purity, the seed samples were analyzed for determination of seed borne mycoflora (fungi) and insects. Damaging effects of seed borne pest were observed on the seed samples, but there were not any life cycles of insect (adult, larva and pupa). The infected seeds were separated from healthy seed. Also for determination of mycoflora (seed borne fungi), with the trace of damaging, shapes of symptoms on the seed and their colour were used for identification of healthy seeds from non-healthy seeds. The infected seeds were cultured on Potato Dextroz Agar (PDA), after growing of fungi, four genera called Penicillium, Alternaria, Aspergilus, Rhizopus and Fusarium were isolated from the seed samples. Moreover, the seed quality (percentage of germination and speed of germination) of infected seeds to seed borne fungi were compared to healthy seeds.