Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2005 | Volume:13 | Issue:1 (19)|Papers Count:9

In order to determine genetic variation among 38 genotypes of Damask rose (Rosa damscena Mill.) for cutting rhizogenesis, sapling establishment and growth components, a study was carried out based on a completely randomized design (CRD) in Kurdistan. The genotypes were cut in March 2004 and planted in greenhouse environment and data were recorded in Aug of the same year. Significant differences (a<0.01) were detected among genotypes for different characteristics including rooted cutting percentage, primary branch number, average height of sapling, average leaf number per branch, average leaflets number per leaf, main branch diameter, the exit point of main branch and sapling vigor, as the suitable factors selection factors for breeding. Mean comparison showed that genotypes 22, 38 and 39 were better than others for all characteristics. Sapling height showed significant (a<0.01) positive correlations with rooted cutting percentage, primary branch number, leaf number per branch, leaflet number per leaf and main branch diameter. Also main branch diameter showed positive and significant (a<0.01) correlation with primary branch number, average height of sapling and average leaf number per branch. The result of cluster analysis showed that the first and final steps of pooling of genotypes carried out in 98.68% and 51.27% respectively, and it was concluded that for similar researches in the future, 13 indicator genotypes could be used, instead of 38 genotypes.

In order to mass propagation of Populus caspica, in vitro matured ovary culture was used. For embryo germination, 14 days old capsules, derived from natural and artificial (twig and pot pollination system) pollination were isolated. Isolated capsules were then transferred to MS, Half-MS (Half concentrated MS) and SS (solidified 3% sucrose solution) hormone free medium for embryo germination. Significant differences (p<0.01) were observed between media and two kind of pollination for mean number of plantlets indication per isolated capsule. High number of plantlets was observed per capsule in half- MS medium. The artificial pollination of catkin showed higher number of plantlets production per capsule than that of the occurring natural pollination (24.77 and 19.46 respectively). Plantlets with 5 or 8 cm height were then cultured in the same medium within jars, before being transferred to the potting soil. More than one thousand plantlets were produced from both kind of pollination. Successfully acclimatized plantlets in green-house were then transplanted to the field.

Acer cinerasens is the most important and useful species of Aceraceae among plants in the Zagrose ecotypes. Regarding difficulties in conventional propagation of hardwood plants specially hard rooting of cuttings from adult trees of Acer, this study was carried out. To investigate shoot tip culture of Acer cinerasens, apical buds and micro cuttings were gathered in different seasons from selected mature trees at Ghallajeh forest in Kermanshah and Sarchahan forests in Shiraz (Gen 1, Gen 2). After different sterilizing treatments, they were cultured on MS (N/4) or DKW media. MS (N/4) medium containing 0.5 mg-1 2ip, 0.1 mg/l Kinetin, 0.05 mg/l TDZ, 0.25 mg/l GA + 0.01 mgl-1 IBA was the best treatment for shoot proliferation and elongation. The shoots were treated as cuttings by different rooting treatments but it was not successful.

In order to study seed germination characteristics of Eremurus spectabilis under physical and chemical treatments, the mature seeds of Eremurus spectabilis were treated by collected from National Botanical Garden of Iran. Seeds were imposed under physical stimulator pretreatments, including soaking of seeds in water for 24-48h, cutting of seeds' tip, making abrasion on seed cortex, exposing to light for 24h, 12h and incubating in darkness. It was also followed by chemically stimulation the seeds, using sodium hypochloride, citric acid and gibberellic acid in different constrations, in order to achieve suitable methods of germination and breaking dormancy. Soaking of seeds in the water for 24-48h, removing seed cortex and washing in 35% sodium hypocholoride and distilled water, cutting seed tip and treat in gibberrelic acid (0.01 M.) and citric acid (50 mg/lit) for 45 minutes and temperature 10-15°C and white light, 24h (4500- 5000 lux) for 1-3 weeks led to the highest germination percentage (53.3%), germination speed (0.88) and seed vigor (10.2).

To evaluate the germination and breaking seed dormancy of Astragalus siliquosus Boiss., an experiment was carried out as a completely randomized design with seven treatments and three replications in Seed Technology Laboratory of Natural Resources Gene Bank, Karaj, Iran. Several treatments, including acid and mechanical scarification and stratification were applied to increase seed coat permeability. Results indicated that about 95% of seed dormancy is due to seed coat impermeability to water and the rest is related to physiological factors. Mechanical scarification with sandpaper was the most appropriate treatment to make the seed coat permeable to water with no adverse effects on embryo. This treatment along with cold stratification removed more than 98% of seed dormancy. Also, stratification of the imbibed seeds increased speed of germination significantly, but had no considerable effects on fresh and dry weights of seedlings. Sulfuric acid, however, increased germination but had maximum percentage of dead seeds. Other treatments had not significant differences with control.

Red clover (Trifolium pratense L.) is one of the important perennial forage legumes that grows naturally in Iran. In order to evaluate relationships between seed yield, forage dry matter yield and their components, 9 accessions of the species were planted and evaluated using a completely randomized block design with three replications in Alborz research center, Karaj, Iran during 2002-2003. The results of correlation analysis showed positive and significant relationships, between forage yield and leaflet lamina area, internode length, petiol length, canopy height, persistency and number of stems per plant. Seed yield had positive and significant relationships with number of stems per plant, persistency and number of seeds per inflorescence. Using regression analysis, the important traits were detected. Number of stems per plant, number of seeds per inflorescence, persistency, number of inflorescences per stem, internode length and number of florets per inflorescence were the important traits for forage yield (R2=99). Using path analysis, persistency and internode length had direct positive effects on forage yield. Number of seeds per inflorescence and number of inflorescences per stem had direct and negative effects on yield, but increased forage yield indirectly through improving persistency and internode length. It was concluded that persistency and internode length were the important triats for improvement of red clover verities. Number of seeds per inflorescence, 1000 grains weight, growth habit, number of inflorescences per stem, number of florets per inflorescence were the important triats for seed yield (R2=98).Using path analysis number of seeds per inflorescence had direct significant effect on seed yield. It was also concluded that number of seeds per inflorescence was the important traits for breeding seed yield in red clover. Although, 1000 grains weight had negative and direct effect on seed yield, indirectly through increasing number of seeds per inflorescence improved seed production.

In order to estimate heritability, prediction of genetic gain per cycle of selection, and relationships among forage yield and quality traits of tall fescues (Festuca arundinacea Schreb.), a polycross nursery containing twenty genotypes was established. At the harvest time, seeds of each genotype were collected. Both seed of half sib families and their clonally propagated parents were grown as spaced plants using a completely randomized design with four replications in Alborz Research Center, Karaj, Iran during 2001-2003. The data were collected and analyzed for dry matter yield, ear emergence date, plant height and plant diameter, water soluble carbohydrate (WSC), crude protein (CP) dry matter digestibility (DMD), crude fiber (CF), acid detergent fiber (ADF) and total ash over two years. The estimates of broad sense heritability (h2b) were average to high (0.44 to 0.92) for dry matter yield and morphological traits indicating the presence of genetic variation for all of them. Narrow sense heritability’s (h2n and h2op) were average to high values for dry matter yield and heading date and lower for plant height and plant diameter, indicating the importance of additive genetic variance in controlling of dry matter yield and heading date and the importance of non-additive genetic variance in controlling of plant height and plant diameter. For all of quality traits the estimates of h2b were average to high (h2b=0.31 to 0.68). The h2n and h20p estimated values were low for WSC and DMD and the same values as h2b for other quality traits indicating the presence of non additive genetic variance for WSC and DMD and additive genetic variance in controlling of other quality traits. Predicted genetic gains per cycle of phenotypic selection for dry matter yield and heading date were 20 and 14 percent improvement from the mean of population. The genetic correlation between WSC and DMD were positively Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research Vol. 13 No.1 132 significant, while the relationships between CP and WSC were negatively significant. The genetic correlation between DMD and CP were inconsistent.Dry matter yield had a negative and non significant relationships with DMD and WSC, but the genetic correlation between dry matter yield and CP were strongly negative.