h. mirzaie-nodoushan

Foliar anatomy of nine species of genus Salix belonging to different subgenera including Salix aegyptiaca, S. caprea, S. cinerea, S. elbursensis, S. euxina, S. issatissensis, S. triandra, S. wilhelmsiana, and S. zygostemon (S. cinerea × S. elbursensis) were studied using light microscope. Several features of leaf anatomy, i. e. transverse section outline, lamina thickness, epidermis characteristics, hypodermis existence, mesophyll features, crystal types, vascular bundles characteristics, etc. are discussed here. Several anatomical characters in this study confirm the infrageneric classification of Salix. On the base of presence or absence of hypodermis layer in lamina, the genus Salix can be divided into two types. The outline of the transverse sections and stomata type differ among sect. Cinerella and the other sections. The delimitation of the closely related species of S. aegyptiaca, S. caprea and S. cinerea belong to sect. Cinerella is difficult, but they can be distinguished based on some anatomical characters. This study has provided interesting results about the studied hybrid S. zygostemon.

Preparing appropriate information on ploidy level and karyotypic characteristics is one of the most important requirements for breeding purposes of all plant species. Regarding the importance of Stipagrostis in sand dune fixation, its drought and salinity resistance and its values as a fodder in better utilization of natural resources in arid and semi-arid areas, investigation of various aspects of this genus is necessary. In Iran, there are numerous populations and species of Stipagrostis on which little study has been done. There is not any attempt to investigate cytogenetics of the genus in Iran and world wide study on this genus is also scarce. Five populations from three species named Stipagrostis pennata, S. plumose and S. karelini were studied in this work. Two ploidy levels were observed in the populations. S. pennata was tetraploid (2n = 4x = 44) and the species S. plumose and S. karelini were diploid (2n = 2x = 22). Chromosome characteristics of the species such as long arm length (L), and Short arm length (S) were measured based on which L/S, S/L and total length of the chromosomes were obtained. Ideograms of the genotypes were also drown. Several parameters, such as TF%, DRL and S% were also estimated for comparing the karyotyps.

This research was carried out to produce interspecific hybrid seeds between the two species of Lolium, L. perenne and L. igidurn. Crossing was done on both single plants in the field and cut flowering stems in laboratory. Immature seeds were collected on the stems in the laboratory after twenty days. These were cultured on MS medium after sterilization. Enough hybrid seedlings were raised on the medium in the laboratory. When the seedlings grown to four leaves stage, they were transfered to plastic pots containing steam sterilized soil. These pots were covered by plastic bags for two weeks for aclimatization. Then the pots were kept in a growth chamber for two months. After complete establishment, the plants were transplanted to the field. Intermediate behaviors was observed on the adult hvbrid plants.

A number of populations of three Loriurn species including L_ mu.worum, L. rigidum and L' perenne, were investigated for cytogenetic characteristics, such as ploidy level, in order to be used in breeding projects of the species. Seeds were germinated and fresh grown root tips were treated with alpha bromonaphtalin, Farmer solution, 1N HCI and hematoxilin as pretreatment, fixative, hydrolize agent and chromosome staining dye, respectively. Mitotic cells were captured at metaphase stage and karyotypic characteristics such as ploidy lever were investigated' A number of populations were tetraploid ancl the rest cliploid. The phenomenon focused in this article was mixoploicly and aneuploicly in the studied populations. Two populations of L. rigidum and L. prenne trisomic phenomenon was observed. Also mixoploidy was observe d in L. igidum and, L. murffiorum, by two levels of polyploidy.

In order to investigate genetic variation between existing cultivars and populations of alfalfa (Medicago sativa), twelve accessions were randomly selected from Natural Resources Gene Bank, and several studies were carried out on them. Seed storage protein electrophoresis was performed on the accessions using SDS-PAGE technique. Based on the results of this study, the protein bands were fairly similar. However, there was a remarkable difference between the accessions based on the two distinct bands. Cluster analysis was also performed on the cultivars and accessions. The accessions with a distinct different band in electrophoresis gel located in a common group in cluster analysis. Over ally, classification based on cluster analysis showed a similar trend to the electrophoresis gel.

To study the effective factors on seed germination of Haloxylon, the effects of four different temperatures on several randomly selected Haloxylon aphyllum and H persicum trees, seeds were investigated. Then seeds were collected from three different positions, top, middle and down part of the trees crown of eight Haloxylon aphyllum and two H persicum which were randomly selected from Yazd province Haloxylon habitats. These were studied for seed germination percentage in five consecutive times with ten hours intervals. The first experiment revealed that not only the genotypes are significantly different for seed germination percentage and the temperatures have different effects on the seed germination of the studied genotypes and species but also there are significant interactions between the two factors, genotype and temperatures. As well as different capacity of seed germination between the trees, the second experiment showed that the seeds from different positions of the trees are significantly different in germination capacity. The seed collected from the top part of the trees germinated better than the seeds collected from lower parts of the trees. This experiment also revealed that the germination speed, between the two species are different and H.persicum germinates faster than H.aphyllum. Fast germination in Haloxylon aphyllum is considered as a way of adaptation to saltyJl1lddrought areas, so that, if enough moisture is prepared for the seeds in a short period, the seeds can germinate and establish very fast.

Since a high level of polyploidy may play an important role in increasing forage dry matter yield, a number of natural populations of Lolium species were investigated for their ploidy level and other kariotype characteristics. In each population of Lolium perenne and L. rigidwn, chromosome characteristics were studied and measured at metaphase stage in five cells. The short and long arms of the chromosomes were measured and analysed. Three polyploid populations were detected within the studied populations. Two populations of L. perenne and one population of L. ligidum were tetraploid with 28 chromosomes. Means of short and long arms of chromosomes, their relative standard errors and the populations karyotypic formula were determined. The three populations were in the same situations based on TF%. Regarding DRL values, since smaler value of this parameter indicates more chromosome asymmetry, one of the L. prenne populations was more symmetric than the other two populations. Based on this parameter L. ligidum population had the most asymmetric karyotype.

When and at which stage in Medics' flowers, pollan grains may grow and fertilize the pistile? How the fragile flowers of medics may be emasculated for inter and intra-specific hybridization, with high percentage of success? This study was carried out to answer these questions. To find the exact time of pollan maturation and their fertilability, the flowers of two species of medics, Medicago polymorpha and M.rigidula were visited at various sizes. And stages Pollan sacs were removed and cultured on agar based media. The best size of the flowers for emasculation before self fertilization was recognized for the two species. This size was about the stage before the tip of the standard petal past its calyx teeth. To emasculate the flowers on the mentioned stage, various density of ethilic alcohol, suction pump, surgical blade and fine/ needle were used. The best method to emasculate the flowers was opening the flowers through standard petal by surgical blade and removing the pollan sacs by suction pump or fine needle. After hybridization, to cover the fragile emasculated flowers to keep them fresh and moist, a glass tube was used, instead of paper bag, for 15 days at 25 degree of centigrade.

To investigate genetic variation between lucern (M Sativa) germplasm, 25 cultivars of the species were studied in a randomized coplete block design in three replications in 1996. Fourteen characters were recorded on the plants of each plot. Regarding analysis of variance, significant differences were found between the cultivars at 5% and 1% levels of probability. In other words, the cultivars were different for the studied characters except for the lenght of main stem of first cut, the lateral stem length of first cut, dry matter yield of first cut, the main stem diameter, growth type and the main stem length of second cut. Regarding dry matter yeild of first and second cut, Bami was the best cultivar. This cultivar also located in a distinct class based on the Duncan classification method. UPGMA cluster analysis divided the cultivars into six groups by cophenetic coefficient of 84%. The cultivars Bami (20319) and 2421 each located in a separate group. Although cluster analysis based on the significant characters divided the cultivars into five groups, the results were similar to the previous classification, so that the cultivar number 20319 (Bami) located in a separate group. Cophenetic coefficient was 82% in this analysis, implying a good fitness of the clustering method.

This study was carried out to determine extent and nature of genetic and non-genetic relationship between some plant characters and to determine selection indices for a selection program in 10 populations of sainfon (Onobrichis sativa) using the best combination of the attributes and their utilization in an indirect selection. Ten accessions, randomly taken from existing accessions of the Forests and Rangelands Gene Bank were used in this study. Accessions were sown in a randomized complete block design with 3 replications. Ten quantitative morphologic and phonologic characters were recorded from seven individual plants per plot. Genetic variance component of the characters were estimated using expected mean square from the table of analysis of variance. This was used to estimate broad sense heritability. The variance covariance matrices were estimated for each of the total, replication, treatment, error and genetic components of variance for treatments using analysis of variance and covariances. Using phenotypic and genotypic variance and covariance matrices and broad sense heritability as the relative economic value, index coefficients were estimated for different combinations of the attributes. The indices with the best genetic gain were used to estimate index value of the studied populations.