Effect of Organic and Chemical Fertilizer on Soil Characteristics and Essential Oil Yield in Dragonhead

We conducted field experiments in two locations to investigation of organic and chemical fertilizer on soil characteristics and essential oil yield in dragonhead. Results showed that the inoculation of bacteria with the seeds in location 1 and also the inoculation of bacteria with the seeds of G₁ genotype in location 2 than G₂ genotype increased the total soil nitrogen content. The application of azocompost and its inoculation with urea's chemical fertilizer comparing to chemical control, it increase the soil carbon content. Results indicated that by increasing azocompost content with a linear procedure bulk density increased. Results showed that application of 100% azocompost treatment had the highest electrical conductivity in the soil. According to the results, the main effect of genotype and fertilizer regime and also two-way interaction (bacteria × fertilizer) had significant relationship with essential oil yield.     

Past,present and future suitable areas for the relict tree Pterocarya fraxinifolia (Juglandaceae): Integrating fossil records,niche modeling,and phylogeography for conservation

European Journal of Forest Research - Pterocarya fraxinifolia, native to the southern Caucasus and adjacent areas, has been widely introduced in Europe. In this study, we investigate the following:...     

First insight into genetic diversity and population structure of the Caucasian wild apple (<Emphasis Type="Italic">Malus orientalis</Emphasis> Uglitzk.) in the Hyrcanian forest (Iran) and its resistance to apple scab and powdery mildew

Investigating population genetic structure and diversity, and resistance to pathogens in crop wild relatives are key steps to assess appropriate conservation and breeding programs. The Caucasian wild apple (Malus orientalis Uglitzk.) is an emblematic fruit tree of the Hyrcanian forest and is supposed to be a contributor to the cultivated apple genome (Malus domestica Borkh. Yet, no study has investigated its population structure, diversity and susceptibility to the two main pathogens of apples, the apple scab (Venturia inaqualis) and the powdery mildew (Podosphaera leucotricha). Here, we investigated population genetic structure and diversity of M. orientalis in the Hyrcanian forest as a mean to identifying future targeted populations for apple conservation and breeding programs. We genotyped using multilocus microsatellite 100 M. orientalis trees sampled in 14 sites. These trees were also screened for presence/absence of six (Rvi6, Vr, Rvi4, Rvi15, Rvi5 and Rvi11) and three (Pl-1, Pl-w, Pl-d) resistance genes to the apple scab and the powdery mildew respectively. Our results showed significant but weak between-site genetic differentiation and isolation by distance pattern suggesting substantial historical gene flow for M. orientalis in this area. We also detected a West-Eastern genetic structure across the Hyrcanian forest with five main populations showing admixture. We also showed a high diversity of resistance genes to apple scab across sites; in contrast, we only found one resistance gene to powdery mildew. These results are a first glimpse to settle wild apple conservation programs in Iran and pinpoint Iranian wild apple populations as an untapped source for apple breeding.     

Molecular approach to determine taxonomic status of <Emphasis Type="Italic">Septoria</Emphasis> sp. causing leaf blotch of <Emphasis Type="Italic">Castanea sativa</Emphasis> in Hyrcanian forests

Castanea sativa is a valuable tree species in Hyrcanian forests, an evolutionary relict ecosystem whose communities suffer from overexploitation and fungal diseases. In the current study, three species delimitation methods were utilized with ITS regions sequencing to determine the taxonomic status of Septoria causing leaf blotch of C. sativa in Hyrcanian forests. The results indicated that the length of ITS region in the genus Septoria (extracted from GenBank) varied from 650 to 680 bp. There were almost three times more variable sites in ITS1 than in ITS2. The ITS2 secondary structure of Hyrcanian Septoria community had the highest similarity with Septoria castaneicola, except for some differences in helix II and III. Also, Hyrcanian samples had minimum genetic distances with S. castaneicola and maximum with Septoria quercicola. The maximum parsimony method divided the studied Septoria genus into three distinct clades, mostly located in clade I. Clade II consisted entirely of Septoria aciculosa, while clade III contained S. castaneicola as well as Hyrcanian samples.     

Phylogenetic relationship and genetic differentiation of Populus caspica and Populus alba using cpDNA and ITS noncoding sequences

Populus caspica Bornm.(section Leuce and subsection Albida), one of the most endangered endemic tree species in the Hyrcanian Forest in Iran, has numerous morphological characteristics that are closely similar to Populus alba; to clarify their taxonomic relatedness and genetic differentiation and thus inform conservation strategies, we used the noncoding regions of chloroplast DNA(cpDNA; trnL-F and trnH-psbA) and the internal transcribed spacer(ITS). Leaf samples were collected from six populations across northern Iran. cpDNA and ITS fragments were amplified by universal primers using the PCR technique and directed sequencing. The results showed that P. caspica is genetically differentiated from P.alba, and two ITS variants were detected within some P.caspica individuals. Conflicts between topologies from ITS and plastid genomes were observed. High differentiation of P. caspica from the other Populus species shown in this study confirmed the diverging taxonomic status of this endangered species. We recommend in situ conservation measures(e.g., protected areas) for at least several populations of this species, especially in the plain regions of the Hyrcanian forest.