Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2002 | Volume:- | Issue:10|Papers Count:10

In vitro plants show an abnormality in growth and photosynthetic performance. In order to understand the role of the main photosynthetic enzyme (RuBisCO) in photosynthetic efficiency (Pm), and the factors affecting activity of this enzyme, an experiment was carried out. The plantlets of wild cherry were examined for some physiological parameters, under three growth conditions (in vitro, and ex vitro after 2 and 4 weeks).The observations showed that under in vitro conditions Pm is too low compared to ex vitro conditions. Changes in Pm of different treatments were consistent with changes in RuBisCO activity. No significant difference was observed between leaf RuBisCO content in vitro and ex vitro. No changes in RuBisCO activity were observed under different growth irradiances (50 and 200 mmol photon m-2s-1) in in vitro condition, while under ex vitro conditions higher RuBisCO activity was observed under higher growth irradiance. Therefore, Pm of in vitro plantlets was affected by low activity of RuBisCO. As previously reported and the results of this study also support it, the low activity of this enzyme could be attributed to presence of sucrose in culture medium and to the low concentration of magnesium ions in leaf of in vitro plantlets.

A simple method was developed to extract sufficient amount of genomic DNA, from plant species containing high amount of secondary metabolites. Leaves of different Amygdalus species including A. scoparia, A. haussknechtii, A. lyciodes, A. elaegnifolia and A. commonis were used for DNA extraction. SDS (instead of CTAB or Sarkosile), NaCl (to remove polysaccharides), PVP (to remove polyphenolic compounds) were used in extracting buffer. Sodium chloride was used again for more polysaccharide removal and RNase to remove RNA. Also, extraction was repeated several times, using chloform: isoamyl- alchohol to abtain more purified DNA. Average yield of DNA, extracted with this procedure was 50 mg per 1 g leaf tissue (70mg/g and 30mg/g in young and old leaf tissues, respectively). Extracted DNAs showed successful reproducibility through PCR amplification. This method which is relatively inexpensive could be efficiently applied for other species of rosaceae or different plant families from which DNA extraction is cumbersome.

In order to propagate Argania spinosa L. skeels, developed ovary culture were used. Seed with hard coat were sterilized with 70% of ethanol and rinsed with sterile water. Hard coat was aseptically removed and ovary was isolated. Two type of Isolated ovary (complete and cut ovary explants), were cultured into the solidified MS, WPM and half- MS (half-concentrated MS medium) for embryo germination. Highest embryo germination was observed in cut ovary explants culture (63.62%). In spite of no significant differences between media for embryo germination, MS medium produced highest embryo germination for both kind of explants (49.52%). Plantlets were successfully acclimatized and transferred to the greenhouse.

Alfalfa is one of the most important forage crops that are highly adaptively to environment unfavorable conditions. High genetic diversity, yield quality and quantity have made alfalfa the most utilised crop in world. One of the most important factors which decrease yield and planting area is soil and water salinity. Selection for tolerant genotypes with suitable planting management would lead to increase yield and cultivation area in saline conditions. Adding Ca2+ to environment by its antagonistic effects on Na+ eads to decrease toxicitic effect of Na+. Therefore, four cultivars namely Golestan (20313), Sistan and Bluchestan, F.A.O (2566) and Ahar Hamedani were arranged in an experimental design to study the Ca2+ effects on growth and yield in saline conditions. Experiment was conducted in RBCD based factoriel in 5 salinity levels in 3 replicates at hydroponic culture. The cultivars were grown in saline condition until the first cutting and then the pots were leached with distilled water. Salinity and Ca2+ levels were added in Hougland nutrient solution and applied the pots. Shoot, root, stem and leaf dry matter, biomass, plant height, main root length, stem internod numbers and tiller numbers per plant were measured Dry matter production has the most significant correlation with stem dry weight in salinity (R2>0.962). Using Ca2+ decreases the salinity effect on above factors, especially in resistant cultivar. Golestan (20313) and F.A.O (2566) cultivars had the most dry matter in Ca2+ and saline conditions.

In order to investigate the possibility of intergeneric hybrid production through artificial crossing between Hordeum spontaneum and Scale cereal, this study was done in Research Institute of Forests and Rangelands. Seeds of S. cereal were planted in pots. Before maturity of pollens and natural pollination, anthers were omitted to emasculate female plants. Pollen grains were gathered from H. spontaneum, then female parents were pollinated with them. Hybrid seeds were formed, and although they were wrinkled but they showed enough germination ability. The hybrid seeds were planted in pots and obtained plants were morphologically between two parents. The hybrid plants flowered, but because of abnormality in meiosis division, seed was not formed. Results therefore, indicated that by artificial crossing intergeneric hybrid seeds can be successfully obtained. However special treatments such as colchicine must be applied to get tetraploid fertile intergeneric hybrids.

In order to investigate asexual propagation of Castanea sativa apical buds were cut in different seasons from selected mature trees at Shafarood Forest in Gillan. After different sterilizing treatments, they were cultured on DKW, QL and MS N /2 mediums. Late autumn was the best season for isolation of buds. Using 0.1% mercuric chloride for 7 minutes proved to be the most effective sterilizing treatment.DKW medium containing 0.5 mg 1-1 BA + 0.1 mg 1-1 IBA was the best treatment for establishment highest shoot proliferation and elongation was observed in DKW medium containing 0.5 mg 1-1 BA + 0.01 mg 1-1 IBA.The shoots were treated as cuttings by dipping the basal ends in 50 mg1-1 IBA solution for 24 hours, then they were placed in an auxin- free GD medium (1.3 macroelement) plus 1% activated charcoal. After 4 weeks, with this technique rooting rates of up to 100%.Rooted plantlets after acclimation transferred to soil under greenhouse condition.

Cocksfoot (Dactylis glomerata) is a perennial grass that is used for pasture and hay production. In order to identify the best varieties for both seed and forage yield, 29 ecotypes/varieties of this species were evaluated under spaced plants using a complete blocks design with three replications, during 2000-2001 in Alborz Research Center, Karaj, Iran.The data were collected and analyzed for ear emergence date, flowering date, stem density, plant height, ear length, ear number, seed yield per ear, seed number per ear, thousand grain weight, seed yield harvest index and forage dry matter yield for mean of each year and combined over two years. The data were also analyzed as split plot in time over the two years.The results showed significant differences among ecotypes/varieties for all traits in both years. In combined analysis over the two years, the genotype, year and genotypexyear interaction effects were significant for all traits.For seed yield, the Iranian ecotypes of Karajl053, Hamadan 1453, Karaj 10112, Pass and 1773 and foreign ecotypes of USA 1634, USA 1715, Spanish1054 and Russia1551 had higher seed production than other ecotypes/varieties over two years. In general, Karaj 1053, Karaj 10112, Karaj 197, Pass and 1773 and Russia 1551 were the best ecotypes/varieties for both seed and forage production.The results of correlation and stepwise regression analysis showed a significant effects of forage yield, seed yield per ear, ear emergence date and harvest index on seed yield production. Therefore, it was suggested to using these characters in cocksfoot improvement programmes.

A number of populations of three Lolium species including L. multiflorum, 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 HC1 and hematoxilin as pretreatment, fixative, hydrolyze agent and chromosome staining dye, respectively. Mitotic cells were captured at metaphase stage and karyotypic characteristics such as ploidy level were investigated. A number of populations were tetraploid and the rest diploid. The phenomenon focused in this article was mixoploidy and aneuploidy in the studied populations. Two populations of L. rigidum and L. prenne trisomic phenomenon were observed. Also mixoploidy was observed in L. rigidum and L. multiflorum, by two levels of polyploidy.