Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2003 | Volume:- | Issue:9|Papers Count:8

This experiment was performed to determine salt tolerance in Salsola dendroides, Alhagi persarum and Aeluropus lagapoides. Seeds were collected from Nouredin Abad Garmsar in a hot and dry climate. After determination of optimum temperarure for germination, effect of salt on percentage and rate of germination was measured. Results showed that increment of salt concentration caused delay in germination rate and decreased germination. Despite high tolerance of halophytes to salt, the maximum germination occurred in salt free medium. The highest and the lowest salt resistance were observed in Salsola dendroides and Alhagi persarum respectively.

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 LIS, 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. rigidum. 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 transferred to plastic pots containing steam sterilized soil. These pots were covered by plastic bags for two weeks for acclimatization. Then the pots were kept in a growth chamber for two months. After complete establishment, the plants were transplanted to the field. Intermediate behaviors were observed on the adult hybrid plants.

Regarding the increasing importance of Aloe species and their utilization in various medicinal, cosmetic and food industries, karyotypic investigation was placed in the work schedule of Research Institute of Forests and Rangelands (RIFR). Young plants were collected from the souther provinces of Iran, where the species has been readily stablished. They were planted in greenhouse conditions at the Institute. Obtaining fresh root tips from the plants, enabled us to carry out normal karyotypic studies on the populations. This article is primary studies on Aloe litoralis species At least four mitotic cells at metaphas stage, were measured for the karyotypic attributes. The karyotypic attributes were long and short arms length of chromosomes, based on which total length of the chromosomes and long arm to short arm length and short arm to long arm length ratios were calculated. Several karyotypic asymmetric parameters were also estimated for comparing the karyotypes. Finally, karyotypes' photographs were prepared, using photomicroscope and idiograms of the karyotypes were also drowning.All of the studied populations were bimodal for their karyotypes and very distinct asymmetry was observed. Significant differences were observed between the populations based on the karyotypic attributes and the studied parameters.

Alfalfa (Medicago saliva) is the most important forage crop which has a good situation for cultivating in saline soils. Four lines named, Golestan (20313), F.A.O (2566), Sistan and Baluchestan and Ahar Hamedani as a tolerant, susceptible, semi tolerant and semi susceptible lines, respectively, were used for evaluation of salinity effects on recovery growth after salinity stress and non stressed conditions. The experiment was conducted in perlyt filled pots in greenhouse which recovered after 5 salinity levels using 3 times replicated experiment in RCBD based factorial design. After second cutting the pots were leached with adequate distilled water and used Hoegland nutrition solution for irrigation. After flowering (third cutting) the height, tiller number per plants, internode number per main stem, leaf dry weight, stem dry weight and shoot dry weight were measured. Recovery after salinity stress showed significant differences in above mentioned characters. Line X Recovery interactions on tiller number per plant, stem dry weight and shoot dry weight were significant at 5% probability. Stem dry weight had the highest correlation to shoot dry weight (R2>0.925).Increasing salinity before second cutting leaded to better recovery and increased higher yield than control plants in all of the lines. F.A.O line (2566) showed the most recovery from stress based on measured characters.

Shoot tips of elite adult trees of Populus caspica in northern forest of Iran (Gillan, Safrabaste) were collected. After sterilization the materials, these explants were cultured in in ½ MS medium with 0.5 mg / lit BA + 0.01 mg / lit IBA.Enough proliferated shoots were obtained. Internodes with length of 0.5 to 1 cm, were cultured in MS and 'isMS with 3 hormone treatments ( BA : 0.1, 0.5 and 1 mg/lit) with three replications. The differences of proliferation and shoot length growth between treatments were investigated with a factorial experiment and Duncan' s test. Results showed that the best medium for internodes' micropropagation of P. caspica, was MS with 0.5 mg / lit BA. Rooting of shoots were obtained in 'is MS with IBA in 0.5 mg/lit.