Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2006 | Volume:14 | Issue:3 (25)|Papers Count:8

Two pot experiments were conducted under a shelter in order to compare transpiration efficiency and relative water content of eight alfalfa (Medicago sativa L.) cultivars. Pots were made of 80 cm long P.V.C. tubes with 10 cm in diameter. During the experiment, plants were harvested five times and each time pots were weighted and the amount of water used and dry matter produced were recorded. During a period of two weeks without irrigation, leaf samples were taken every 3 days and relative water content was measured. Cultivars used different amount of water and produced different amount of dry matter in each growth period. However, differences were not significant at whole growth period. Cultivars Hamedani and Diabloverde which showed the highest values of transpiration efficiency also had the highest values of relative water content at 65% soil water content, while Sequel and Yazdi had the lowest values. Cultivars with highest values of transpiration efficiency are suggested to be better for cultivation under mild water stress conditions.

The objectives of this experiment were to evaluate of genetic variation and relationships among 20 accessions of Bromus inermis. The experiment was conducted as a randomized complete block design with 3 replications. Results of variance analysis showed significant differences between the accessions for different traits. There was considerable phenotypic and genotypic variation for forage yield and number of stems per plant. Broad-sense heritability was very high (90-98%) for days to pollination, days to heading and plant height. For number of stems, flag leaf length, peduncle length, forage yield and crown diameter, broad-sense heritability ranged between 67-87%. Correlation coefficients showed that forage yield per plant had a high and negative correlation with days to heading and days to pollination, but a high and positive correlation with plant height, peduncle length, flag leaf length, flag leaf width, number of stems and crown diameter. Using principal component analysis, the first three components determined 90% of the total variation. Days to heading, days to pollination, plant height, peduncle length, flag leaf length, forage yield and number of stems per plant were the most important traits in first component. Accessions were classified into 3 groups with distinct variations for forage yield, plant height, tiller number and maturity time. Thus, crossing plants from genetically diverse populations may result in superior progenies for cultivar development.

Large-leaved lime is one of the important trees in North forests of Iran. Different parts of the tree are being used for different purposes. Seeds of the plant don't germinate easily because of the existence of double dormancy (mechanical and physiological). This research was conducted using factorial experiment based on complete randomized design with 3 replicates. Five treatments were applied to the seed following surface disinfection using 1% sodium hypochlorite. The treatments included three and six months chilling (4±1°c) on the top of paper or in sand. Two concentration of gibbrellic acid (250 and 500 ppm) after stratification. Scarification with concentrated sulfuric acid for 10 or 20 min. Pretreatment of seeds in alternate temperature(15/ 25°C, night/days) for 3 months in sand before chilling. Direct seeding (with or without scarification) in pots and maintaining in field conditions. The results showed that sowing seeds in sand significantly (P<0.01) increased germination rate and the best treatment was chilling for 6 months. Seed germination was showed no significant increase by use of GA after chilling. Sulfuric acid did not show any effect on seed germination. There was not any significant difference between alternate temperatures before chilling and chilling for 6 months. Number of germinated seeds increased from 11 to 32% when seeds were scarified and cultured under field condition. Chilling practice of 6 months duration after surface disinfection was the most effective treatment for germination of large-leaved lime seeds.

Conventional propagation of Rosa damascena is limited attributed to low adventitious root formation on cutting- In vitro culture has become an alternative method for propagation of this plant species. Shoot proliferation and in vitro rooting of two Azarbayjan genotypes using different concentration of growth regulators- West Azarbayjan genotype needed 0.01 mgl-1 TDZ, 0.5 mgl-1 IBA to attain proliferation of only 1.33, while east Azarbayjan genotype required 0.01 mgl-1 TDZ, 0.1 mgl-1 IAA to obtain a maximum shoot multiplication (2.33). Among different concentration of BAP and Kin, the highest multiplication rate (2) in west Azarbayjan genotype was found at 5 mgl-1 BAP. East Azarbayjan genotype reached to its maximum shoot multiplication (3.2) at 2.5 mgl-1 BAP. In order to root regeneration, in vitro propagated shoots were transferred into modified MS medium supplement with different concentration of NAA. East Azarbayjan and west Azarbayjan produced shoots rooted on modified MS medium containing 0.1 and 0.2 mgl-1 NAA, respectively. However, in this research East Azarbayjan genotype had better responses than West Azarbayjan.

Bunium persicum is an important medicinal plant with dormant seed and it is established and distributed only in its natural habitats. This research was conducted, using a completely randomized design with 3 replications and two observations. Seeds were collected from Semnan province and stored for 2 weeks at 4°C. Then seeds were imposed under chemically stimulator, soaking in 1) KNO3 (50mM), 2) K2SO4 (50mM) and 3) polyethylene glycol (PEG) (250g/1)for nh, 4) gibberelic acid (500ppm) for 5h, 5) kinetin (100 ppm)for 1h, 6) combination of gibberelic acid (500ppm) and kinetin (100ppm) for 1h, 7) control. Results showed that KNO3, K2SO4 and PEG had no significant effects on seed quality characters. Applying hormones as pre-treatment caused higher percentage of germination but combination of kinetin and gibberlic acid promoted germination, total speed of germination and vigor index.

Acer cinerasens is the most important and useful species of Aceraceae. Regarding difficulties in conventional propagation of hardwood plants, specially rooting of cutting in adult Acer trees, this study was carried out. To investigate in vitro culture of Acer cinerasen, seeds were gathered in different seasons from selected mature trees at Sarchahan forest in Shiraz. For culture of mature embryos, seeds were washed with running tap water for 2 days and then surface sterilized with 0.1 % (W/V) mercuric chloride. The embryos were aseptically dissected and transferred in a modified MS medium. Seedling emergence after 4 weeks ranged from 35%. After acclimatization, seedlings were transferred to soil under green house condition. Regarding difficulties in conventional propagation of Acer, specially Acer cinerasens, this study led to production of plants through embryo culture that will be important.

Cocksfoot (Dactylis glumerata) is a perennial grass that being used for pastures and hay production. In order to evaluation of quantity and quality variation of 36 genotypes of Dactylis glumerata, an experiment was carried out using an unbalanced RCBD in Agricultural and Natural Resources Research Center of Zanjan. Forage yield, plant height, heading date, leaf to stem ratio, digestibility, protein, soluble carbohydrates, crude fibre, ADF, NDF and ash content were evaluated. After calculating correlation coefficients between traits, related traits to yield and quality were determined. Genotypes showed significant differences for all traits, except for crud fiber, ash and ADF. To determine the best varieties and populations, trait means were compared: Genotypes 21, 32, 19-33, and 28 had the highest yield.Based on heading date comparisons, genotypes 3-25 and 32-36 were located in very early maturity class and genotypes 1, 2, 6, 17,21,27,28 and 30 were located in very late maturity. Considering digestibility, genotype 21 was the most digestible with 67.19 percent. For protein content, genotypes were divided into 4 groups among which genotype 21 with 22.68% had the highest protein content In general, it is possible can plant genotypes 1,3,8,10 together with 17, 21, 24, 32 and 36 in order to achieve synthetic seeds through open pollination.