Search

Soil drought stress is a limiting factor of productivity in walnut (Juglans regia L). Ferredoxin (Fd) level decreases under adverse environmental stress. Functional replacement of decreased Fd by Fld (Flavodoxin) had been shown to have protective effect under abiotic stress condition. This study aimed to evaluate four transgenic lines (L3, L4, L13 and L17) along with non-transgenic line under three osmotic stresses levels (0, 10 and 12% PEG). This experiment carried out based on a completely randomized design with four replications. To confirm that the Fld gene is successfully integrated into the walnut genome, PCR and dot blot analysis were carried out. The transgenic lines of walnut expressing Fld displayed increased tolerance to osmotic stress at 10 and 12% PEG condition. Lines expressing Fld exhibited increasing tolerance to drought stress and maintained health of plants under osmotic conditions. Results of real time PCR showed that expression level of Fld gene in L4 was higher than the others. Among transgenic lines, L4 was more tolerant than other lines under osmotic stress. These findings indicate that expression of Fld gene can increase tolerance to osmotic stress in Persian walnut and is useful tool for walnut production in arid and semi-arid regions.

In order to investigate the interaction of genotype × trait and relationships among agronomic traits on 12 maize hybrids, an experiment was conducted in a randomized complete block design (RCBD) with three replicates in four regions of Karaj, Birjand, Shiraz, and Arak. Results of analysis of variance indicated that most of the genotypes were significantly different in terms of agronomic traits. Mean comparison by Duncan's method showed that KSC705 genotype was more favorable than other genotypes in all studied regions. SC604 genotype in Birjand and Karaj regions and KSC707 genotype in Shiraz region have higher rank than other genotypes. Correlation analysis was used to investigate the relationships between traits. In most of the studied regions, traits of number of grains in row and number of rows per ear were positively and significantly correlated with grain width and grain weight with grain yield. Graphical analysis was used to further investigate. Genotypes–trait interaction graph explained 59.27%, 61.22%, 59.17%, and 61.95% of total variance in Karaj, Birjand, Shiraz, and Arak, respectively. Based on the multivariate graph, KSC705, KSC706, and SC647 genotypes were identified as superior genotypes in all studied regions and KSC400 genotype did not show much response to change in traits. Correlation between grain width and number of rows in ear, plant height and grain length, one thousand grain weight and grain thickness, and ear diameter with number of grains in row was positive and significant. The results of classification graph of genotypes also divided the cultivars in to three groups as follows: KSC703, KSC400, and KSC706 genotypes in the first group; DC370, SC604, and SC301 in the second group; and KSC260, KSC704, KSC707, and SC301 in the third group.

BackgroundFlower development and sufficient fruit set are important parameters with respect to walnut yield. Knowledge about flowering genes of fruit trees can help to conduct better molecular breeding programs. Therefore, this study was carried out to investigate the expression pattern of some flowering genes (FT,SOC1,CAL,LFYandTFL1) in Persian walnut (cv. Chandler) during the growing season and winter dormancy.ResultsThe results showed that walnut flower induction and initiation in Shahmirzad, Iran occurred in early June and late September, respectively. After meeting chilling and heat requirement, flower differentiation and anthesis occurred in late-March and mid-April to early-May, respectively. Study of flowering gene expression showed that the expression of theFTgene increased in three stages including before breaking of bud dormancy, from late March to late April (coincided with flower differentiation and anthesis) and from late May to mid-June (coincided with flower induction). LikeFT, the expression ofSOC1gene increased during flower induction and initiation (mid-May to early-August) as well as flower anthesis (mid-April to early-May).LFYandCALgenes as floral meristem identity genes are activated byFTandSOC1genes. In contrast with flowering stimulus genes,TFL1showed overexpression during winter dormancy which prevented flowering.ConclusionThe expression ofFTgene activated downstream floral meristem identity genes includingSOC1,CALandLFYwhich consequently led to release bud dormancy as well as flower anthesis and induction. Also,TFL1as a flowering inhibitor gene in walnut showed overexpression during the bud dormancy. Chilling accumulation reducedTFL1gene expression and increased the expression of flowering genes which ultimately led to overcome dormancy.

Trachyspermum ammi is a well-known pharmaceutical plant in Iran and has many medicinal properties including anti-digestive, anti-spasm, antimicrobial, antiviral, and relieving rheumatic pains. This plant is important for its essential oil and its main constituent; i.e., thymol. Several properties of this plant are related to this valuable constituent. This research was conducted to increase thymol content of this plant by genetic transformation using Agrobacterium tumefaciens. To enhance thymol production, we used TPS2 gene (Terpene Synthase 2), which is a key enzyme involved in thymol synthesis pathway. In this research, an effective genetic transformation system was developed for Trachyspermum ammi with Agrobacterium tumefaciens. To overexpress TPS2 gene in Trachyspermum ammi, a gene construct called pBI121-TP harboring the neomycin phosphotransferase (nptII) gene as a plant-selected marker was designed. This work was performed using three strains of Agrobacterium tumefaciens (LBA4404, GV3101, and EHA101), hypocotyl explants, and factors including inoculation time (5, 10, 15, and 20 min) and co-cultivation time (1–3 days). Polymerase chain reaction (PCR) and Southern blot analysis were performed to confirm the integration of TPS2 and nptII transgenes into the plant genome. Based on these findings, the EHA101 strain in 5-min inoculation and 1-day co- cultivation showed a higher efficiency compared to two other strains. Transformation efficiency varied between 6.12 and 18.36% based on the Agrobacterium strains for transformation. The qPCR results demonstrated that the TPS2 gene was more expressed in the transgenic plants than non-transgenic plants. HPLC analysis showed that the aerial part of transgenic plants has the greater thymol compared to the non-transgenic plants. To the best of our knowledge, this study demonstrates, for the first time, a suitable and efficient method for overexpression TPS2 gene to enhance thymol by Agrobacterium-mediated transformation method in Trachyspermum ammi.

Basil (Ocimum basilicum L.) is one of the most important culinary and aromatic plants in Iran. Surprisingly, no commercial cultivar is available across the country and farmers are cultivating landraces. The main purpose of the present study was to describe the diversity among and within landraces of sweet basil as well as developing new genotypes for cultivar development. Twenty two genotypes of basil including Iranian landraces and international cultivars were evaluated in a randomized complete block design with three replications in 2017. Three Iranian landraces, ‘Isfahan3’, ‘Birjand’ and ‘Malayer’ were recognized as superior landraces. Dry herb for them was recorded as 3309, 3191 and 3175 kg ha−1, respectively. Also, the content of essential oil in ‘Isfahan3’, ‘Birjand’ and ‘Malayer’ was obtained as 1.43, 1.85, and 1.79% (w/w on dry weight basis), respectively. Due to existence of high diversity among landraces, broad-sense heritability estimates were over 98% for all of the evaluated traits. Among these landraces, 14 full-sib families were produced via controlled pollination. In another experiment the full-sib families were compared. For all measured traits, there were highly significant differences among full-sib families. The best family in each landrace was selected for cultivar development in future breeding programs.

The most popular Iranian cantaloupe ‘Samsoori’ is highly susceptible to devastating viruses transmitted by Aphis gossypii. A dominant gene (Vat) causing resistance to the aphid and viruses was detected in ‘Ginsen Makuwa’ in spite of its low fruit quality. They were crossed and the segregating offspring were assessed for combining favorable traits with Vat gene. In the F2 population, moderate to high broad-sense heritability estimates were found for measured traits including, fruit weight (0.78) and soluble solid content (SSC) (0.7). The F3 families were significantly different from each other for earliness, fruit shape indices, cavity, flesh thickness, SSC, and fruit numbers per plant. Resistant and susceptible plants were determined by genotyping 210 plants in F4 generation using a dominant DNA marker for the resistant allele of Vat gene. Out of 15 selected F3 families, four were susceptible, three were homozygote resistant and six showed segregation in their progeny for the Vat gene. Selection assisted by Vat gene marker was a very useful and applied approach for the identification of healthy plants along with phenotypic selection.

The purpose of this research was to evaluate the combining ability of six local Iranian and one imported cantaloupe cultivar. Heritability of traits was estimated using a half-diallel mating design. Seven parents and their crosses were evaluated in 2013 and 2014. The greatest general combining ability (GCA) for yield and fruit number was for “Rish-baba” (0.53 kg/plant and 0.3, respectively). The cultivar “Ananasi” had the highest GCA for fruit weight and soluble solids content (SSC) (0.088 kg and 1.4, respectively). “Ananasi” presented the highest GCA values for fruit firmness, chlorophyll a and b and carotenoid content, as well as the highest total chlorophyll content. The cross Garmak × Rish-baba showed the highest specific combining ability (SCA) for yield with heterosis value of 99%. High heritability estimates for SSC (0.52), flesh thickness (0.61) and concentration of chlorophyll a (0.7) were obtained. Although there were significant SCAs for yield, the parents are suggested to be improved prior to hybrid development. The parent “Ananasi” appears to be a suitable donor in breeding programmes.

Salinity and drought are major abiotic stresses affecting wheat (Triticum aestivum L.) production throughout the world, and discovery of loci for traits affecting yield under salinity may lead to the breeding for salt-tolerant plants. In the present study, 186 F10 recombinant inbred line (RIL) populations were evaluated under salt-stress conditions in order to identify main-effect and epistatic-effect quantitative trait loci (QTLs) for 15 traits in wheat during the germination and early-seedling stages. In total, 61 main-effect QTLs on 15 chromosomes and 21 epistatic interactions on 12 chromosomes were detected through composite interval mapping (CIM) and a mixed-model-based CIM method. Two major QTLs for primary-leaf fresh weight and coleoptile fresh weight were detected on chromosome (or linkage group) 5B2 and 2D, respectively, which contributed ~44% and 43% of the phenotypic variance. Additionally, 12 QTL clusters including different traits were detected on 1A1, 3A, 4A, 2B1, 3B, 5B1 and 2D1. Candidate genes were identified within QTL regions and gene ontology (GO) enrichment analysis was performed. In total, 9134 candidate genes were grouped into 274 GO terms (including 79 GO terms involved in the ‘biological process’ category). These genes directly or indirectly play a vital role such as lipid localisation, biological regulation, fatty acid biosynthetic process, cellular process, DNA conformation change, translational elongation, carbohydrate metabolic process, Fe ion homeostasis, hydrogen peroxide metabolic process, and pigment biosynthetic process at the germination and early-seedling stages under salt-stress conditions.

Fennel is used for various purposes in medical, cosmetic and food industries and Iran is one of its main producers. In this study agro-morphological and phytochemical diversities of Iranian fennel landraces were assessed. According to phenological properties, Iranian fennels were classified as early, medium and late maturity. Based on two years data, late and medium maturity fennels had the higher amounts of vegetative and reproductive traits. In term of seed yield, medium maturity fennels had a better performance, and in term of essential oil content medium and late maturity fennels had the highest values. With considering essential oil yield the highest values were related to medium and late maturity landraces. According to GCMS analysis, in essential oil of the studied Iranian fennels, trans anethole content ranges from 1.24 to 88.45, methyl chavicole from 0.22 to 59.1, fenchone from 1.22 to 14.74 and limonene from 5.5 to 15.71%. Trans anethole chemotype landraces were belonged to arid areas of eastern Zagros and southern Alborz; methyl chavicole chemotype landraces to humid areas of western Zagros and northern Alborz; fenchone chemotype landraces to late maturity landraces from humid area of northern Alborz; and he highest limonene contents to landraces from areas with mediocre altitude in north of Iran. Based on path analysis, as morphological markers to improve seed yield, negative selection of days to 50% flowering and positive selection of weight of dry biomass, and to improve essential oil contents positive selection of days to 50% flowering severely are highly recommended.

The compositions of essential oils of 22 accessions belonging to nine Salvia species of Salvia nemorosa, Salvia sclarea, Salvia macrosiphon, Salvia verticillata, Salvia eremophilsamia, Salvia aethiopis, Salvia virgata, Salvia reuterana and Salvia limbata, from Iran were assessed. The concentration of essential oil yield obtained by hydrodistillation ranged from 0.07 to 0.71%. GC–MS analysis revealed 73 compounds in these plants. The main constituents were linalool (0.6–51.58%), linalool acetate (0–52.61%), e-caryophylene (3.08–60.58%), germacrene-d (0–25.16%) spathulenol (0–35.4%) and caryophyllen-oxide (0–37.89%). The accessions were separated into five chemotypes using cluster analysis in light of the six major compositions. Results showed a significant variation in compositions and yield of essential oils among and within Salvia species. The chemical variability could be attributed to genetic and environmental factors. The analyses indicated that some of accessions collected from south had more amounts of essential oils yield than other regions.

Rapeseed (Brassica napus L.) is important for edible oil production in semi-arid areas. Abiotic stresses are threatening rapeseed production in such areas. This study was conducted to find tolerant genotypes of rapeseed and to determine which traits of crop establishment is related to abiotic stress tolerance. Hydrotime model parameters were determined in a laboratory germination test, and seedling emergence and growth were evaluated in pot experiments under control, drought, salinity, deep sowing, low and high temperatures for 19 rapeseed genotypes. Results indicated that the predicted germination time courses at the various water potentials generally fitted well with the observed germination data. The estimated values of θ H, ψb(50), and σψb differed significantly across genotypes. Seedling emergence and growth differed significantly under each environmental condition. PCA showed that genotypes of Hayola 401 and line 285 were the most tolerant to abiotic stresses during crop establishment and seedling growth. The first PC explained 40% of variations, and a correlation was observed between PC1 and ψb(50). Correlations among hydrotime model parameters and early seed vigour variables indicated that ψb(50) negatively correlated with seedling emergence percentage and rate (day−1) under all abiotic stresses. It shows that genotypes with more negative values of ψb(50) have more seedling emergence percentage and a larger seedling emergence rate (days−1) under a wide range of environmental conditions. Thus, it can be concluded that, to identify tolerant genotypes of rapesee to abiotic stresses, ψb(50) is a good trait and that breeders can focus on reducing ψb(50) to increase tolerance of abiotic stresses.

The sugarcane germplasm collection located in Khuzestan, Iran, is one of the most important genetic resources with valuable accessions from different continents. However, this collection has not been properly used by breeders due to the extremely large population. The aim of this study was to phenotypically characterize the sugarcane germplasm and form a mini-core collection. Hence, 13 morphological traits were evaluated on 253 accessions. The primary germplasm was grouped into 10 clusters based on partial repeated bisection (RB) data, where the smallest cluster contained three accessions from two breeding centres (USA and Cuba). Using principal component analysis (PCA), the first two PCs (principal component) explained 59.5% of the total variation. A mini-core of 21 accessions was created by using the maximization strategy, with a low mean difference percentage (MD = 2.31%) and large coincidence rate of range (CR = 93.96%). The sugarcane mini-core represented the major diversity of the primary collection. The means and medians between the mini-core and the primary collection did not differ significantly. Accessions with high sugar and cane yield, originating from the USA, Cuba, Argentina, and South Africa, were in the mini-core collection. In this paper, we established, for the first time, an applied mini-core collection in sugarcane germplasm. The mini-core collection, as a breeding collection, is a highly suitable, manageable, and efficient subset for the enhanced use of sugarcane germplasm in breeding programs.

Medicinal plants play a key role in the human health and have a huge share in the global economy. Cultivation of Salvia species is increasing mainly due to high commercial worth of this plant in food, medicine, perfumery, and cosmetic industries. The aims of this research were: (1) to determine drought tolerant Salvia spp. and (2) examining drought stress effects on germination and seedling growth, separately. Seeds of 36 Salviaaccessions (15 species) collected from different regions of Iran were primarily treated by soaking and gibberellic acid was used to break the seed dormancy. Afterwards, germination rate, percentage and early seedling growth were measured in two separate tests with four osmotic potentials: 0 (control), -0.3, -0.6, and -0.9 MPa using polyethylene glycol (PEG, 6000). The principal-component analysis (PCA) summarized all traits into two components ("germination" and "seedling growth") in all osmotic treatments. There was significant correlation between germination traits and among seedling growth traits in -0.3 and -0.6 MPa, but correlation between the traits of two components was not significant. Tolerance of genotypes to drought stress in germination and seedling stage showed a high diversity. Tolerant accessions for both components are suitable for cultivation in controlled conditions, but tolerant accessions only for "seedling growth" component, probably would be appropriate for distribution in their habitats for conservation purposes. However, the accessions which simply germinate at water stress conditions, but are susceptible at seedling stage, will die and lose their seed bank in the soil. Key words: Germination, medicinal plant, osmotic stress, polyethylene glycol (PEG), Salvia, seedling growth.

A primary concern of modern plant breeding is that genetic diversity has decreased during the past century. This study set out to explore changes in genetic variation during 84 years of breeding by investigating the germination-related traits, inter-simple sequence repeat (ISSR) fingerprinting and osmotic stress tolerance of 30 Iranian wheat (Triticum aestivum L.) cultivars. Seeds were planted under control and osmotic stress (−2, −4 and −6 bar) in three replications. The ISSR experiment was carried out using 32 different primers. Genotypes were divided into two groups (old and new) each containing 15 members. The results of ANOVA showed that highly significant differences existed among genotypes and among growth conditions. The results showed that during breeding in some traits such as coleoptile length and seedling vigor index, a significant decrease has been occurred. New cultivars had a mean coleoptile length of 33 mm, shorter than that of old cultivars (42 mm) under osmotic stress of −6 bar. Genetic variance of root length, shoot length and seedling vigor index for old cultivars were 1.59, 1.93 and 45,763, respectively, significantly higher than those for new cultivars (0.55, 1.08 and 27,996, respectively). This difference was also verified by ISSR results as the polymorphism information content was 0.28 in old cultivars, higher than that of new cultivars (0.26). These results prove this claim that during breeding, genetic diversity has decreased for many germination-related traits and breeders are better to pay more attention to genetic diversity.

In Iran, there is a high diversity of salvia species and accessions which includes 70 species that 40% of them are endemic. The objective of this investigation was to find a practical treatment for germination of salvia species, particularly, endemics and to find conservation issues and appropriate approaches. We observed that there was a huge diversity in color (RGB channels), seed area and 1000-seed weights among the population in this study, including 60 accessions (23 species) that thirteen of them (five species) are endemic of Iran. These accessions were soaked in four gibberllic acid (GA3) levels (0, 100, 150 and 200 mg/L). The germination rate and percentage of 62% of accessions were, extremely, increased in response to the GA3 treatment; nonetheless, some accessions did not germinate at all which indicates that there are demands for more efforts to conserve these accessions. Germination percentage of endemic species was significantly lower than non-endemic ones, indicating a serious concern for their conservation. A significant correlation between the 1000-seed weights and area under germination percentage curve (AUGPC) was found that indicates seeds were evolved to have more storage to survive for a long time until germination. Key words: Conservation, endemic, Iran salvia diversity, germination, gibberllic acid (GA3).

In order to study the effect of drought stress on morphophysiologic characteristics,yield and yield components of 8 new hybrids of corn (Zea maize L.) and KSC704commercial hybrid as control resistant to drought and warm (which were bred andscreened in Khozestan province condition), an experiment was conducted in aRandomized Complete Block Design (RCBD) with three replications underdrought stress and normal irrigation at Khorasan-Razavi Agriculture ResearchCenter, Mashhad, Iran on June 10, 2011. The results of analyze variance showedthat under normal irrigation and drought condition, there was a significantdifference (p