Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2008 | Volume:16 | Issue:1 (31)|Papers Count:12

Genetic diversity is one of the most important criteria to select parents in breeding programs. Morphological characters and chemical composition, including plant height, tiller number, biomass, dry yield, dry yield! biomass, dry leaf/dry yield, macro and micro elements, crude protein, dry matter, crude fiber and ash percentage were measured in 18 alfalfa cultivars. The multivariate statistical procedures, such as cluster analysis (UPGMA) and principal components analysis were used. The results showed significant differences among genotypes for morphological traits. Genotype 13 and 15 showed the highest values for most of the studied traits. The Genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV) and heritability (Hb) parameters were estimated for the characters. Hb for plant height, dry yield and leaf/dry yield were 0.81, 0.94, 0.82, 0.89, 0.68 and 0.80 respectively. Amount of P.C.V were 14.251%, 21.86%, 26.58%, 23.71%, 12.49% and 27.88% respectively, and the G.C.V were 9.67%, 18.84, 18.52%, 18,34%, 6.84% and 18.51, respectively. Based on the morphological traits, the genotypes could be classified into four clusters. Ninty for percent of variance among the genotypes were justified by the first two PCAs. Based on chemical traits they were classified into five groups and 73.492% of variance was explained by the first four principal components. Dry yield, protein percentage and Ca had higher portion of variance.

In this experiment genetic variation, heritability and relationships among traits were studied in 21 accessions of Dactylis glomerata L. under field conditions. The experiment was conducted as a randomized complete block design with 3 replications. Results of analysis of variance showed significant differences between accessions for most of the traits There was considerable genotypic coefficient of variation for forage yield per plant. Broad-sense heritability was high for days to heading, flag leaf length, days to pollination and forage yield. Correlation coefficients showed that forage yield/plant had a high and positive correlation with number of stems, flag leaf length, peduncle length, flag leaf width, plant height, and crown diameter. Using principal components analysis, the first three components determined 79% of the total variation. Cluster analysis grouped the 21 accessions into 3 clusters with cluster 1 containing accessions with lower forage yield and height and medium values for other traits. Accessions in cluster 2 and 3 had respectively higher and lower values for the traits when compared to accessions in cluster 1. Iranian accessions were mainly grouped in cluster 1 and 2. Our results indicate presence of comparable genetic potentials in Iranian populations of Dactylis glomerata L. for cultivar development.

Sophora L. (Fabaceae) is a perennial plant and its roots reportedly have antibacterial properties. In this study, we examined 6 populations, representing 3 species, including Sophora alopecuroides (S.T, S.K and 10423), S. moms (4512) and S. pachycarpa (S.M, 3548). Mitotic chromosomes were studied in meristematic cells of root tips obtained from germinated seeds. The basic chromosome number was x=9 in all of the populations, but their ploidy level varied. According to Stebbins' categories, all of the populations placed in symmetric class of 1A, indicating a symmetric karyotype. Based on inter and intra chromosomal variations, S. pachycarpa had the most asymmetric and evolutionary karyotypes and S. moms had the most symmetric karyotypes. Analysis of variance based on unbalanced completely randomized design showed a significant difference (P<%l) among the populations for all of the traits. Using principal components analysis, the first two components justified %99.897 of the total variance. For the first component, the length of long arm and total length of chromosome, with the highest coefficients of eigen vectors, were the most important traits. For the second component, the arm ratio, centromer index and the length of short arm had the most important role for total variation. Cluster analysis (UPGMA methods) classified the populations into three groups. The populations S.M, 3548 and S.T classified to first class and S.K and 10423 stand to second class. Also the population 4512 was grouped to third class. The diagram of the populations dispersion, based on two first components, the populations were grouped in three separated classes, which agrees with the results of cluster analysis.  

Iran and the east of Mediterranean area is the main center for genetic diversity of Persian clover (Trifolium resupinatum). To investigate the genetic diversity of Persian clover for primary (T. resupinatum), secondary (T. clusssi) and tertiary (T. fragiferum) gene pools, 359 accessions were evaluated in the field according to IPGRI descriptors in 2003. Days to flowering differed from, 22 to 100 days, 40 to 52 days, and 50 to 130 days for the primary, secondary, and tertiary gene pools, respectively. Thousand seed weight means were 1.15, 0.49, and 1.23 g in the primary, secondary, and tertiary gene pools, respectively. In T. fragiferum, mainly showed prostrate growth habit trait, one accession showed growth habit that could be used in the agronomic systems. Phenotypic variation (CV) and Shannon indices showed high levels of diversity for most of the traits. A positive linear relationship between stem length at the flowering as depended trait with growth habit and days to flowering traits expressed of 58.6% (r2=0.586) variation. Cluster analysis classified the gene pools in three groups. Landraces from primary gene pool appeared in the first cluster, whereas in the second cluster the wild germplasm of primary gene pool came together with secondary gene pool materials. Finally, the tertiary gene pool germplasms revealed in the third cluster. Existence of high levels of diversity in the primary, secondary and tertiary gene pools of Persian clover in National Plant Gene Bank of Iran can provide a potent germplasm for improvement of high potential Persian clover lines.

This research was carried out to identify and introduce the threatened and endemics plant species of Markazi province, determine the habitat of these plants and define important effective environmental factors on the species. The database of the red species list of Markazi province flora, was obtained from literature, and then in field surveys, the present of each individual listed species and information about life form, some topographic, edaphic, and distribution factors in each habitat, were registered. The results showed that in Markazi province there are 202 red plant species belonging to 30 families and 98 genera of which 182 species (90.09 %) are endemics of Iran flora. The families with high number of red species include, Papilionaceae (42 species) and Asteraceae (34 species), and the main genera were Astragalus (35 species) and Cousinia (15 species). There are 10 endemic species in Markazi province flora, of these 6 species are in Data Deficient (DD), 3 species in Vulnerable (VU) and 1 species in Low Risk (LR) status and also three species Allium hirtifolium, Ferula Assa-foetida and Dracocephalum kotschyi are in Endangered (EN) status. Herbaceous perennials (50 %) and bush & sub-shrubs (28.21 %) were the most important life forms of red species, and also 66.67 % of VU and EN species was herbaceous perennial. The mountainous areas of this province (> 2000 m altitude) contain 66 % of total province red species flora. The habitats with high number of red species were: Rasvand mountain (69 species), Mowdar mountain (35 species), Sefid-Khani mountain (23 species), Arak (22 species), Alvand mountain (20 species) and Lathe-dar mountain (17 species). As a result, the main factors affecting on red species are limited geographical distribution and human impacts.

Physiological response of Haloxylon aphyllum to drought stress was evaluated in Shahid Sadouqi desert research station of Yazd with geographical coordinate of 54, 11" 9" longitude and 32, 4', 30" latitude during 2001-2005. A factorial experiment based on completely randomized design with 3 replications was applied. After planting and establishment stages, the experimental treatments including pot capacity, one third capacity and non-irrigation were applied in weighing lysimeters. Experimental treatments were applied in the second year and then physiological characters including plant water potential, leaf osmotic potential and root osmotic potential were measured from late June until late September in 15 day intervals. To evaluate the interaction of environmental factors, such as temperature on physiological factors, the measurements were done just before sunrise and in the afternoon. Results showed that plant water potential, leaf osmotic potential and root water potential were significantly (p<0/01) affected by the treatments. Recording date also affected significantly (p<0/01) the physiological traits. On the other hand, results showed that haloxylon drought resistance is partly related to low water potential in plant due to low leaf osmotic potential. Variation of osmotic potential along experimental period showed high osmotic adjustment capacity in plant.

Acer monospessulanum is one of the important forest species in western forests of Iran. Its populations decreased in recent years. Because of embryo dormancy and hard seed coat, its seed has both physiological and mechanical seed dormancy. The optimal treatment for breaking dormancy and seed germination enhancement of this species was investigated. A completely randomized design with 3 replicates were used to compare the effects of 3 and 6 months chilling (4±1°c) on the top of paper or in sand, 2 concentrations 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 and direct seeding (with or without scarification) in pots and maintaining in natural conditions on seed germination of Acer monospessulanum L.. The results showed that sowing seeds in sand significantly (p<0.01) increased germination rate and the best treatment was chilling for 6 months (33%). Seed germination was not significantly increased by GA3 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 in Acer increased when seeds were scarified and cultured under the natural conditions (35.6% vise 11%). Chilling (6 months) was, therefore, the most effective treatment for germination of Montpellier maple seeds.

The species of Trifolium differ from each other based on morphology and cytogenetic characters. For study of karyotype variation, 11 species of Trifolium were selected from North- West in Iran and karyological study was performed on number, size and type of chromosomes. Results of karyological studies in root tip samples showed that nine species were diploid with x=7 or 8 and two species were tetraploid with x=8. Based on A1, A2, TF%, SC and formula of karyotype T.pratense and T. canescens had much symmetricalkaryo type. Analysis of variance for seven karyotype characters (L, S, L/S, CI, DRL, L+S, and TL) based on randomized complete design with five replications was performed. The results showed significant differences between the species (p<0.1).T. canescens had the highest total length (L+S), long (L) and short arm characters. For arm ratio (LIS) trait, T.hybridum had the highest and for CI T. pratense showed the highest average values. Also the highest DRL value was, obtained in T. arvense and the highest TL value was obtained in T. ambiguum and T. repens. Cluster analysis divided the species into 4 groups. The highest metric distance was obtained between T. canescens and T. hybridum, and lowest metric distance values were obtained between T. phleoides and T. striatum. The species which located in same group have similar karyotype, so they can be used in interspecific crossing.

This study was carried out in Agricultural and Natural Resource Research Center of Esfahan during 2004-2006. Karyotypes of 5 fennel populations were studied, using root tip mitotic cells. The base chromosome number was x= 11 for the studied popurations. Number of chromosomes, length of the longest chromosome, length of the shortest chromosome, longest/ shortest length ratio, average of long arm/short arm ratio, average of short arm/long arm ratio, average of chromosomes ratio were recorded. The types of chromosomes were metacantric, submetacentric and telocentric. Comparison of relative length of the shortest chromosome (S%) showed that Lorestan and Fozveh-Najafabad populations with 75% and 72.72% relative length of the shortest chromosome, respectively, had more symmetric karyotype and Esfahan population with 33.33% relative length value had less symmetric karyotype.

Study of the salinity tolerance in medicinal plants is very important for cultivating them in saline lands. A factorial experiment based on completely randomized design was carried out in order to study the effect of salt stress on 'Foeniculum vulgare' plants in hydroponic condition. The accessions of F. vulgare were originated from Isfahan, Ardabil, East Azerbaijan, Europe, Tehran, Yazd, Estahban and Shiraz. Salinity levels include 0 (control), 50, 100, 150 and 200 mM sodium chloride with four replications in the germination stage and three replications in the seedling stage. The results showed a significant reduction in germination rate, germination percentage, roots length, shoots length, plants vigor, root dry weight, shoot dry weight; shoot weight/root weight and biomass with increase of salt stress. There was a significant difference between accessions at presence of salt. Shiraz accession showed the lowest reduction in germination stage compared with the control. In the seedling stage, Yazd accession showed the lowest reduction compared with the control.