Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2006 | Volume:13 | Issue:4 (22)|Papers Count:10

Genetic potential and variation of 27 Haloxylon aphyllum genotypes from several arid areas of Iran were evaluated during 1998-2003. Experiment was carried out using a randomized complete block design with three replications in Hossein-Abad station in Qom province. Plant height, stem diameter and canopy cover and plant vigor were analyzed. Analysis of variance and pooled analysis were done. According to the results in the whole years plant height and stem diameter were significant (P<0.01) in 5 years.. The genotypes were significantly different for all of the studied traits based of pooled analysis except for plant vigor. Interaction effect of year and genotype was not significant in all of traits. Genotypes number 18 and 22 (of Sistan and Baluchestan), 12 and 14 (of Semnan), 1 and 6 (of Yazd) were higher in plant height, stem diameter and canopy cover. Genotype number 22 was higher in plant vigor.

In order to evaluate the germination and breaking seed dormancy of Astragalus tribuloides an experiment was carried out as a completely randomized design with eight treatments and three replications in Legume laboratory of Agricultural Faculty of Tehran University in Karaj, in 2006. The seeds were treated using different methods of scarification and stratification. Results indicated that the most percentage of germination was observed in the scarification treatments (with or without chilling, about 97%). Also, vigor index and germination speed were higher in those treatments. Mechanical scarification with sandpaper was the most appropriate treatment to make the seed coat permeable to water with no adverse effect on embryo. The lowest germination occurred in control, stratification, hot water and freeze-thaw treatments. Considering low germination percentage in seven days stratification (without scarification), hardness of seed coat could be suggested as a major reason of dormancy in Astragalus tribuloides.

Stipagrostis species grow in dry areas particularly in sand dunes. Several species of this genus are highly important in sand dune fixation as well as forage values. This research was carried out to investigate the possible effects of various geographical locations on karyotypic characteristics of four Stipagrostis pennata populations. Karol Pearson correlation coefficients were estimated for all of the combinations of populations based on five karyotypic characteristics. The results indicated that the populations have a significant correlation (P<0.01) based on short arm length, long arm length and total length of the chromosomes. The correlations were also significant (P<0.05) for the ratios of long arm length to short arm length and short arm length to long arm length. Thus, it could be concluded that climatic conditions have no major effect on karyotypic characteristics.

In order to determine water extract proteins and their effects on ruminal degradation, alfalfa hay, clover, sainfoin, salad crop and com silage along with two range forage species including Latium prenne and Glyceria plicata fries (GPF), were used. Extractions were made with deionized water and soluble proteins in the extract were precipitated using 75% (v/v) acetone solution. The precipitated proteins were separated by SDS-PAGE. The insoluble residues along with whole samples were used for ruminal degradation using gas production technique. The highest soluble protein percentage belonged to the salad crop and the lowest percentage was belonged to GPF forage (P<0.05).Non significant difference between whole samples and insoluble residue samples suggested that the value of soluble proteins as a factor for dry matter degradability is limited.

Eucalyptus is an important exotic species in Iran from industrial, medicinal and ornamental points of view. Different species of Eucalyptus demonstrate various responses to salinity. This research was carried out to estimate the salinity resistance of three Eucalyptus species at germination and seedling stages. The effects of five NaCl concentrations (0, 50, 100, 150 and 200 mM) on three Eucalyptus species (Eucalyptus camaldulensis, E. salubris, E. tetragona) were studied under factorial and base of completely, randomized design, with three replicates in growth chamber. One way analysis of variance was used to estimate reaction of every species to salinity.Also analysis of variance was applied to identify differences between different species and saline treatments in respect to seed and seedling characters, including radicle length, plumule length, vigour index germination percentage, germination speed and germination index. The results showed that there was significant difference between the species in respect to their germination percentage, vigour index, and germination speed, but the difference between radicle length, plumule length and germination index was not significant. The effects of different salinity levels on the seed characters were significant, whereas the effects of species salinity interaction were only significant on radicle length, vigour index, germination speed and germination index. The species performed different seed characters at different levels of salinity. Effects of NaCl concentration on different traits were significantly different. Comparison of means classified the species in different classification. Also probit analysis was used to estimate LD50 and indicated that between three species E. salubris is the most resistant to salinity.

In order to study yield quality of five species of annual Medic, an experiment was performed in form of split plot design with two factors and four replications. The main factor was irrigation (dry and irrigated) conditions and the second factor was species (M. laciniata, M. radiate, M. polymorpha, M. orbicularis and M. scutellata). For determination of forage quality, samples were collected from shoot of species and protein, calcium, ash, phosphorus, dry matter and oil percentages were analysed. Species showed no significant differences for protein percentage in irrigated and dry conditions and M. orbicularis had the most protein percentage in dry condition, but percents of calcium, phosphorus and oil were more in irrigated than in dry condition. In addition, the most oil percentage belonged to M. laciniata and M. scutellata in irrigated condition. M. orbicularis had the most protein and calcium percentage in dry condition and it is a suitable species for dryland or range regions. M. scutellata and M. radiata had the most ash, phosphorus, protein and calcium percentages in irrigated conditions and they are suitable species for use in lay farming systems.