Physical and nutritional properties of hawthorn fruit (Crataegus pontica L.)

Hawthorn, from Rosaceae family, is one of the important forest fruits which there are different species in Iran. In this study, some characteristics of hawthorn fruit (Crataegus pontica), including physical properties (fruit length, width, thickness, geometric, arithmetic and equivalent mean diameter, surface area, sphericity, aspect ratio, thousand fruit mass and true density) and nutritional properties (total dry matter, total soluble solid, titratable acidity and moisture content) were considered. Results showed that average of fruit length, width and thickness were 1.53 mm, 1.95 mm and 1.78 mm, respectively. The geometric mean diameter was same to arithmetic mean diameter (1.75 mm), while equivalent mean diameter was higher than both (1.76 mm). Some physical properties such as sphericity (1.13 %), surface area (1.69 mm) and aspect ratio (1.26) were determined. Average of 100 fruit weight in this species was 306.54 g and it is estimated 3.06 g for one fruit. Total soluble solid percent (TSS) and titratable acidity percent (TA) of fruit hawthorn were estimated 18.7 % and 1.71 %, respectively

Assessment of genetic structure among different pear species (Pyrus spp.) using apple-derived SSR and evidence of duplications in the pear genome

Simple sequence repeat (SSRs) markers derived from Malus were used to assess their transferability in the analysis of the genetic diversity and relationship of some Pyrus species. All studied microsatellite loci produced fragments and were polymorphic among the studied samples. Fifty-one allelic variants were detected at eight SSR loci, ranging from five (MS14h03, CH02b10 and CH03g06) to nine (CH02h11a), with a mean of 6.37 alleles per locus. A relatively high level of diversity was recorded among the studied accessions. The average of Shannon's index (I) was 1.04. The Dice genetic similarity coefficient ranged greatly and ‘Khoj 1’ (a member of P. communis) and ‘Shinko’ (a cultivar belonging to P. pyrifolia) had the lowest (0.21) values, while ‘Chojuro’ and ‘Nijisseiki’, two cultivars belonging to P. pyrifolia, had the highest genetic similarity (0.97) among the studied samples. Bayesian cluster analysis and principal coordinates analysis plot separated the P. pyrifolia samples from other species, and formed three distinct groups, indicating high genetic differences between P. pyrifolia and other studied pear species. Several private alleles were observed in some of the studied species that would be of great importance for species identification. Furthermore, in 23 samples, more than two alleles were observed in the CH04e03 locus, indicating presence of locus duplication in these samples. Our observations suggest that, for this locus, at least two homologous chromosomes or genomic regions may be presented in the genome of some pear samples

Genetic variation of some hawthorn species based on phenotypic characteristics and RAPD marker

Hawthorn (Crataegus spp.) is an important forest fruit species in Iran. Genetic variability among some genotypes of hawthorn was investigated using morphological traits and random amplified polymorphic DNA (RAPD) marker. The collected genotypes belonged to four species of Crataegus genus. High variability among genotypes was found for most of the traits. Results from the principal component analysis (PCA) indicated that 85.05% of the observed variability was accounted by the first five components. The first two components explained about 55.24% of the total achieved variability. In PCA, fruit weight, fruit length, fruit diameter, fruit moisture, fruit dry matter, leaf length, leaf area, leaf width, number of leaves per node, seed weight and seed length were predominant in the first two components, indicating that they were useful for the assessment of hawthorn germplasm characterization. A total of 58 polymorphic bands were produced with 10 RAPD primers. The bands' sizes ranged from 180 to 2700 bp. The number of the observed polymorphic bands for each primer ranged from 4 to 8, with an average of 5.8 alleles per locus. The polymorphism information content was observed to be the highest (0.79) in the Oligo_32 locus, whereas the Oligo_339 locus had the lowest value of 0.64, with an average of 0.72, among the RAPD primers. The Jaccard's genetic similarity coefficient ranged from 0.12 to 0.95 among the genotypes. At a similarity coefficient of 0.46, the unweighted pair group method with arithmetic mean (UPGMA) cluster analysis divided the genotypes into three major groups

Phylogenetic analysis among some pome fruit trees of Rosaceae family using RAPD markers

To evaluate the phylogenetic relationships among subtribe Pyrinae of Rosaceae, 50 different genotypes and cultivars of pome fruit trees were collected from various locations in Iran, and analysed using random amplified polymorphic DNA (RAPD) markers. Altogether, 85 polymorphic fragments were produced by 11 random 10-mer primers. The number of produced bands varied from 4 to 12 for each primer, 7.72 on average. The lowest Jaccard's genetic similarity coefficient was scored between apple cv. ‘Akan’ and a wild Pyrus syriaca pear (0.04), and the highest similarity was observed between two genotypes of P. syriaca (0.97). Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) properly separated the accessions and divided them into three major groups, including Malus, Pyrus, Mespilus and Crataegus. Members of Mespilus and Crataegus were further separated and formed two subgroups. Analysis of the genetic structure, using STRUCTURE and phylogenetic relationship using TreeView software confirmed the results of the UPGMA dendrogram and properly distinguished different genera. Among different genera studied in our experiment, Malus was the most distinct one and showed high genetic distance from other genera. Generally, the results from the present study provide valuable information about the genetic relationship among important pome fruit trees in Iran and indicate that, although Mespilus is genetically close to the Crataegus genus, it has relatively high similarity with Pyrus and Malus. Moreover, outcomes of this research confirmed that RAPD molecular markers are an appropriate means for evaluation of the genetic relationship among various genera of pome fruit trees

Evaluation of some walnut genotypes in the west of Iran using fruit characteristics and RAPD marker

Persian walnut (Juglans regia L.) belongs to the family Juglandaceae is one of the most important nut crops in Iran. In this research, morphometric and genetic variations among some genotypes of Persian walnut collected from different parts of west Iran were evaluated based on nut characteristics and RAPD markers. In the first experiment, 29 traits related to nut and kernel were used to evaluate genetic potential of 119 walnut genotypes. The primary results of fruit morphometric characteristics showed that there is high variability in the some evaluated traits such as fruit shape, nut diameter and Kernel removal from nut in studied genotypes. Also, in the second experiment, the genetic diversity among 50 genotypes of walnut was evaluated using 13 RAPD markers. A total of 87 alleles were produced in the 13 RAPD markers with their sizes ranging from 140 to 2500 bp. The number of observed alleles for each locus ranged from 4 (OPA-18 and OPA-13) to 11 (OPA-09), with an average of 6.46 alleles per locus. Shannon's information index (I) value was observed to be highest (3.20) in the OPA-09 locus, while the OPA-13 locus had the lowest value (0.70) with an average of 1.66 among RAPD locus. The Jaccards’ genetic similarity coefficient ranged from 0.08 to 0.79 among genotypes. Finally, our results demonstrate some of these genotypes have been desirable traits and must be conserved as valuable genetic resources, from the perspective of breeding

Genetic diversity within and among two-spotted spider mite resistant and susceptible common bean genotypes

Two-spotted spider mite (Tetranychus urticae C. L. Koch, 1836), is one of the most destructive herbivores of common bean. Very little is known about the diversity among resistant sources in this crop. The present study was conducted to characterize 22 resistant and susceptible common bean genotypes by 8 Simple Sequence Repeats (SSRs) and 8 Random Amplified Polymorphic DNA (RAPD) markers. These SSR and RAPD primers produced 100 % and 81.8 % polymorphic bands. Based on RAPD fingerprints and SSR profiles, pairwise genetic similarity ranged from 0.0 to 0.857 and from 0.125 to 1, respectively. The resistant and susceptible common bean accessions were grouped together in the dendrograms generated from RAPD and SSR clustering analyses. The results indicate that RAPD and SSR analysis could be successfully used for the estimation of genetic diversity among genotypes. SSR markers could group genotypes according to their resistibility and susceptibility to the spotted spider mite but RAPD could not. Therefore, the SSR markers can facilitate the development of resistant common bean cultivars through breeding programs against T. urticae.</p