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Linum species are of various benefits to mankind, such as fiber and oil source, ornamental as well as medicinal values. Population genetic study by using molecular markers can produce valuable information on genetic structure, genetic variability, genetic fragmentation and gene flow among plant populations. These data can be used in conservation and breeding programs of economically important plants. We performed population genetic study on 6 populations of two Linum species, namely L. usitatissimum L. and wild species L. austriacum L., by using SRAP molecular markers. In general low genetic variability was observed in both studied species, but a little higher genetic diversity occurred in the wild species L. austriacum (6.25-21.88%). AMOVA revealed significant genetic difference among these populations that was supported by Gst and Dest parameters of genetic differentiation. K-Means clustering and STRUCTURE analyses identified three distinct genetic groups within each species. Nm and population assignment test did not show the occurrence of gene flow among the studied populations and suggested genetic fragmentation in both Linum species. Predominant selfing in L. usitatissimum may be the reason for genetic uniformity within each population and genetic differentiation among these populations. L. austriacum shows distyly, which promotes pollination between different floral morphs, and prevents self-pollination. This may be the reason for higher degree of within population genetic variability in this species. [ABSTRACT FROM AUTHOR]

Cultivated cotton species Gossypium hirsutum L. and Gossypium barbadense L. are considered as the highest yield producing cottons, which are cultivated in several regions of Iran. Due to long time selection and cultivation practice, we need to broaden the cotton gene pool by producing new hybrids. Interspecific hybrids ensued after crossing G. hirsutum and G.barbadense. In the present study, cytogenetic charactristics and genome size of parental cotton species (G. hirsutum L. and G. barbadense) and their F1 and F2 hybrid progenies were studied. All cotton genotypes showed 2n = 4x= 52 chromosome number. The genotypes differed significantly in cytogenetic charcaters like number of total intercalary, and terminal chiasmata, mean number of ring chromosomes and quadrivalents (P < 0.05). The genome size of the genotypes varied from 1.345 to 4.37 picograms. This research revealed cytogenetic variability among the cotton offspring and if these are combined with agronomic characteristics, they can be used in cotton breeding. [ABSTRACT FROM AUTHOR]

Cotton (Gossypium hirsutum L.) is an important commercial crop that is cultivated in irrigated lands. Screening and selection of cultivars showing enhanced adaptation to drought is a target of cotton breeding programs. In order to study genetic variability in cotton genotypes under drought stress, eight cotton cultivars were screened using a 17% PEG treatment. Ten pots -each containing 5 seeds from each genotype- were planted using a randomized complete block design. Pots were distributed in two groups: with seedlings facing drought stress, and with well watered seedlings that were taken as controls. Twenty inter simple sequence repeat (ISSR) loci were used to determine genetic diversity. Four of the eight genotypes namely N2G80 and GT40 were rated as showing enhanced adaptation to drought stress while SKT133 and Bakhtegan were drought sensitive. The number of effective alleles -as measured by ISSR- varied from 1.189 (SKT133) to 1.363 (GT40). GT40 and SKT133 genotypes showed the highest and lowest gene diversity and percentage of polymorphism respectively. The highest number of specific alleles occurred in plant samples that were under drought stress. The high number of specific alleles in cotton plants under drought stress supports genetic changes in repeated motif changes within microsatellite regions. This genetic difference may be due to sequence changes in the genome or epigenetics. [ABSTRACT FROM AUTHOR]

Hybridization is one of the main strategies in cotton breeding producing new genotypes and increasing the genetic diversity in the cotton germplasm available. Thirty RAPD and ten ISSR markers were use to assess the genetic diversity in F2 progenies of tetraploid cotton hybrid genotypes (Gossypium hirsutum). Fifteen of 30 RAPD primers produced 126 reproducible bands with 66.44% polymorphism. Among the primers used, OPA09 primer showed highest value of number of effective allele (Ne), Shannon index (I), Nei's genetic diversity (H) (1.814, 0.638 and 0.447 respectively). The value of genetic identity varies from 0.65 between Siokra x No.200 and Tabladila x Siokra to 0.93 between Tabladila x Sindose and Sindose x No.200. Eight of 10 ISSR primers provided 87 reproducible bands with 67.82 % of polymorphism. UBC834 primer with AG repeats as a core sequence showed the highest value of Ne (1.570), I (0.477) and H (0.323) while combined primer UBC807+(GA)9T showed the highest PIC value (0.500). Based on ISSR data obtained, the hybrid cultivars Mehr x Tabladila and Tabladila x Siokra showed the lowest Nei's genetic identity (0.59), while, the hybrid cultivars No.200 x Belilzovar and Tabladila x Sindose showed the highest value. UPGMA Dendrograms obtained in RAPD and ISSR as well as combined RAPD and ISSR markers grouped together the hybrid genotypes which have Mehr cultivar as one of their parents. In conclusion, this study showed that using combined RAPD and ISSR data provides higher resolution of molecular profiles in hybrid genotypes [ABSTRACT FROM AUTHOR]

Sargassum species are one of economically important brown algae in south of Iran. In this study, morphological variation was assessed in three Sargassum species widely distributed species in the southwest of Iran (Oman sea): Sargassum tenerrimum J. Agardh, Sargassum glaucescens J. Agardh and Sargassum ilicifolium C.Agardh. At each site, ten different nonproductive individuals were selected with a minimum distance of 2-3 meters at low tide or snorkeling. We investigated ten measurable and ten categorical morphological parameters from three localities (Chabahar, Quatr and Tang) using ANOVA test as well as factorial analysis. The ANOVA test performed among populations of each species as well as among species showed significant difference (p<0.01) for all quantitative characters used. Different clustering like UPGMA and Neighbor Joining separated populations of each species studied based on measurable characters while both measurable and categorical characters have main rules in differentiation of three species PCA analysis confirmed cluster analysis. In total, both measurable and categorical characters enable to discriminate species while categorical parameters studied did not vary among populations of each species studied. This is the first study on evaluation of inter-population variation of Sargassum species in Iran. [ABSTRACT FROM AUTHOR]

Pomegranate Punica granatum (Lythraceae) is one of the most important horticultural plants of Iran cultivated in different areas with different cultivars having specific fruit characteristic such as size, color, time of ripening, disease resistance, taste, etc. The present study considers morphological and RAPD analysis of eighteen pomegranate cultivars of the country. Agro-morphological characters were studied by using factor analyses. Clustering separated cultivars in distinct groups indicating their morphological differences. Forty RAPD primers used produced 182 bands, out of which 414 bands were polymorphic (about 44%) with average of 4.55 polymorphic bands for each primer. Eight unique bands (cultivar-specific) were observed. Two cultivars of Malas Yazdi and Poost Ghermez Mamooli showed the highest similarity among the cultivars studied [ABSTRACT FROM AUTHOR]

Meiotic analysis of 11 populations of 6 Hordeum species showed normal chromosome pairing and chromosomes segregation during anaphase in most of the anaphase and telophase cells, except few cases of laggard chromosomes, chromosome stickiness and tripolar formation. Cytomixis and chromosome migration occurred in different directions from early prophase to telophase-II in some of the species and populations studied leading to the formation of aneuploid cells and also formation of the meiocytes having double the normal chromosome number. Such unreduced meiocytes formed unreduced pollen grains. Two to five percent of the pollens formed were bigger in size and could be considered potential unreduced pollen grains. Other meiotic abnormalities caused some degree of pollen sterility. [ABSTRACT FROM AUTHOR]

An efficient medium culture for clonal mass propagation was established for the propagation of banana (Musa acuminate L.) cultivar Cavendish Dwarf including the salt formulation of Murashige and Skoog, 30 g/L of sucrose, N-phenyl-N-1, 2, 3- thiadiazol 5-yl Urea (0.5 mg/L) and indoleacetic acid (2 mg/L). Fifteen decamer RAPD primers were used to study somaclonal variation among the regenerated plants of the first, third and fifth sub-cultures. Eight out of fifteen primers produced 143 bands in all the genotypes studied. Fifty-three bands (37.70%) were common in the parental genotype as well as in the regenerated plants while 90 bands were polymorph (63.30%). Twenty-five specific bands were observed in the parental genotype and the regenerated plants of different sub-cultures which may be used in genetic descrimination of the genotypes. The presence of specific bands in regenerated plants indicates the rearrangement in certain loci during tissue culture due to somaclonal variation. [ABSTRACT FROM AUTHOR]

RAPD markers variations were studied in ten pomegranate cultivars. Twenty RAPD primers used produced 323 bands. Nineteen bands were common in all the cultivars while other bands were polymorph. Some specific bands were identified in the cultivars studied which may be used in cultivars discrimination. Primers OPB-07 produced the highest number of polymorphic bands (5.9%[U1] ), while primers OPI-16 produced the least number of polymorphic bands (5.2%[U2] ). Different similarity coefficients determined among the cultivars studied, showed the highest value of genetic similarity was observed between Abdandan and Suski cultivars while Shasavar and Shahidaneh cultivars differed from the other cultivars and stand far from them in NJ and Bayesian trees. Some specific bands/loci were observed in pomegranate cultivars studied which may be used for cultivar identification. [ABSTRACT FROM AUTHOR]

RAPD analysis was performed in 13 upland cotton (Gossypium hirsutum L.) parental genotypes and F2 back-cross progenies. Out of 20 primers used 17 primers produced reproducible bands. In total 329 bands (loci) were obtained out of which 242 bands were polymorph and only 87 bands were common in cotton genotypes studied. Some of the cultivars showed presence of specific bands while, some bands were present in all except one genotype. Some bands were absent in the parental genotypes but present only in back-cross progenies, whereas some bands occurred in the parental genotypes but absent in back-cross progenies. Parental genotypes differe significantly in the number of loci from back-cross progenies and different back-cross progenies also differed significantly from each other indicating genetic diffrences of the genotpyprs studied which is also supported by clustering of the genotypes [ABSTRACT FROM AUTHOR]