Iranian Journal of Horticultural Science and Technology
Year:2008 | Volume:9 | Issue:2|Papers Count:7

To investigate the genetic relatedness of Iranian local apples with introduced commercial cultivars and to evaluate the genetic diversity among local ‘Golab’ apples, 27 genotypes were assessed at genomic DNA level with 28 primer pairs of Simple Sequence Repeat (SSR). Twenty two SSR primers that produced distinct and scorable DNA bands were considered for analysis. The number of SSR primer loci detected among the 27 genotypes ranged from three to 11 alleles with an average of 5.4 alleles per primer. The polymorphic information content (PIC) among accessions varied from 0.37 to 0.77 with a mean of 0.68, showing high level of heterozygosis. The dendrogram constructed using the unweighted pair group method with arithmetic (UPGMA) method grouped the cultivars into five sub-clusters according to their geographical origins. Based on the dendrogram, clear-cut separation was found between Iranian apples and introduced cultivars. All the non- Iranian accessions jointly with one local apple, Ahar-2, were clustered together, while Iranian genotypes were classified in separate clusters. The closest genetic similarity was found among ‘Golab’ genotypes collected from different regions. The close relationship among Iranian ‘Golab’ apples as well as their similar morphological traits supports the hypothesis that Iranian ‘Golab’ apples possibly originated from a common ancestor.

The genetic diversity of 23 bermudagrass populations and 4 hybrid cultivars                  (Cynodon dactylon × Cynodon transvaalensis) were assessed by some morphological traits and ISSR markers. Fourteen morphological traits were evaluated in a randomized complete block design with three replications. Genetic distances were calculated based on the square Euclidean distance and dendrogram were generated with the Ward׳s clustering method. Cluster analysis revealed that genotypes were categorized in three groups for plant height. Fourteen primers were used to study of genetic diversity of genotypes by ISSR markers. Totally 336 fragments were produced by these primers which 305 of them were polymorphic bands. After evaluation of similarity matrice of molecular data based on the Rogers distance, genotypes were classificated by Between Group׳s clustering method. In this cluster, genotypes were categorized in four groups. Triploid cultivars and diploid populations were belonged to the same group and separated from tetraploid populations. The results showed that there was no significant correlation between similarity matrices of morphological and ISSR markers.

Gravitational irrigation systems have many disadvantages for availability of water and nutrient elements in plant growth. In this research, water and urea fertilizer use efficiency has been compared, in four traditional and pressurized irrigation systems, using heavy isotope of nitrogen (15N) and neutron scattering. The field experiment was carried out as a randomized complete block (split plot) design on lettuce. Different irrigation systems (main factor) consisted of trickle fertigation (T1), sprinkler fertigation (T2), sprinkler irrigation with soil fertilizer application (T3) and  furrow irrigation (T4) and different plant organs (sub factor) consisted of outer and inner leaves, stem and root. The results showed that, there were significant differences (at 5% level) between lettuce canopy yield and were recorded 86.3, 77.2, 72.2 and 60.3 tonha-1 for the treatments T1, T2, T3 and T4, respectively. Trickle fertigation had the highest potential for outer leaves, stem and root production and sprinkler fertigation system had the highest potential for inner leaves production. Plant under trickle fertigation had the highest stem and the lowest leaves production and this was recorded in reverse order in sprinkler fertigation. In T3 treatment, 64.4% of nitrogen in lettuce, was derived from the labeled fertilizer and in comparison with other treatments, that was very high (T1=51.1%, T2=46.4% and T4=42.4%). Because of high total nitrogen and Ndff, nitrogen use efficiency was increased in T3 treatment (up to 65.8%). The nitrogen use efficiency in T1, T2 and T3 were 53.0%, 41.4% and 19.9% respectively. The lowest water consumption and the highest water use efficiency were recorded in sprinkler fertigation (2918 m3ha-1 and 26.46 kg m-3, respectively). On the other hand, the highest water consumption and the lowest water use efficiency were recorded in furrow irrigation (10948 m3ha-1 and 5.51 kgm-3, respectively). In other words, in sprinkler fertigation with use of one fourth of water, the amount of yield was increased up to 28% (in comparison with furrow irrigation). It seems that split application of fertilizers in 8 increments in normal soils (with normal level of nutrient elements) is not suitable for lettuce culture. It is recommended that the total amount of fertilizer requirement should be applied 30-51 days after planting of the lettuce (the most of it should be applied 40 days after planting). In this condition, increasing expectation of fertilizer use efficiency (over 60%) is possible in sprinkler fertigation treatment.

Despite high genetic diversity of native pears, little is known regarding the genetic relationships among pear germplasm in Iran. The objectives of this study were based on determining genetic variations among well known cultivars of pear in Iran using Simple Sequence Repeat (SSR) markers. Genetic diversity in 27 genotypes of pear was assessed using 19 pairs of SSR primers that amplified a sum of 120 alleles. Based on the dendrogram, clear-cut separation was found between P. pyrifolia (Asiatic pears) and P. communis germplasms. Iranian wild genotypes including different Khuj accessions as well as three commercial cultivars, ‘Dom-Kaj’, ‘Shah-Miveh’ and ‘Sebri’ were clearly separated from other genotypes tested. Clustering ‘Sebri’ together with other Iranian wild accessions in a different group from P. pyrifolia, reconfirmed this hypothesis that all Iranian pears belong to P. communis. European cultivars in concert with two local pears, ‘Mohammad-Ali’ and ‘Sard-Roudi’, were placed in the same cluster, whereas French genotypes jointly with Iranian genotype ‘Dare-Gazi’ were classified in the neighboring cluster. The results showed that the Iranian pear cultivars have closer affinity with European and French pear cultivars than Asian pears. These results suggest that SSR markers have higher level of discrimination in evaluating genetic diversity and fingerprinting of pear genotypes.

This study was carried out to appreciate forcing and reduce the glasshouse period of Narcissus flower ‘German’ production. Experiment was performed in Faculty of Agricultural Sciences, the University of Guilan, in 2006. The experiment was conducted as a factorial in a completely randomized design.  with 8 treetments and 3 replications. Treetments include temperature (Control and 4°C) and gibberellic acid (GA3)Tat 0, 200, 400, 600 mg l-1 cincentrations. The parameters such as sprouting time, day to flower stem emergence, flowering time, flower stem length, stem diameter, leaf length,  leaf number, number of floral bud, number of vegetative bud, bulb diameter and bulb weight were measured. The results indicated that bulb exposure to low temperature accelerated sprouting, flower stem emergence and flowering. Leaf length, stem diameter and stem length were also increased. GA3 at the concentration of 600 mgl-1 had significant effects on shoot growth (leaf and stem quality) and sprouting when compared with other concentrations.

Boston fern (Nephrolepis exaltata Schott cv. Bostoniensis) is one of the most important foliage indoor ornamental plants. Today, mass propagation of this plant through in vitro culture techniques is exploited as a common commercial method. In the present investigation an attempt has been made to achieve the optimal conditions for Boston fern shoot proliferation. The experiments were conducted in factorial arrangement in a completely randomized design. In vitro shoots (3-7 mm length) that had been grown on medium containing half strength of MS mineral salts, 20 gl-1 sucrose and 1 mgl-1 BA were used as explants. They were cultured on 12 different nutrient media containing two concentration of mineral salts (1/2MS and b 1/4 MS) two concentration of sucrose (20 or 30 gl-1) and three concentrations of benzyladenine (BA), (2, 1 and 0.5 mgl-1). The number and height of shoots and dry, and fresh weight of foliage were measured after 6 weeks. The results showed that studied factors had significant effect on measured variables. On the medium containing half concentrations of mineral salts, 30 gl-1 sucrose and 2 mgl-1 BA, higher number of shoots was obtained (25±0.5 with 5±0.5 mm heights). Green globular bodies (GGB) (meristemic rounded structures) formation were also measured. GGB was formed on media containing high concentration of BA (1 and 2 mgl-1). Precise investigations of GGB have showed that they are meristematic centers that would form lateral buds. Hence these media were selected as the best medium for shoot proliferation of Boston fern.