نشریه نهال و بذر
سال سی‌ام شماره 1 (بهار 1393)

In this research, the chromosome 1 of rice was studied to identify QTLs controlling traits associated with drought and salinity tolerance at germination and seedling stages using F2:4 population derived from a cross between two cultivars, Gharib (tolerant to drought and salinity) and Sepidroud (sensitive to drought and salinity). Two hundred and thirty six polymorph markers (105 AFLPs and 131 SSRs) were used to construct genetic map of the rice chromosome 1. Thirteen SSR and seven AFLP markers with length of 216.1 cM were mapped on chromosome 1 and average distance between adjacent markers was 10.8 cM. In total, 17 QTLs controlling germination rate, germination percentage, radicle length, plumule length, coleoptile length and drought and salinity tolerance indices at germination stage under four different conditions (drought stress induced by PEG and sorbitol, salinity stress induced by NaCl and non-stress conditions) and four QTLs controlling shoot potassium concentration, root/shoot length ratio, root dry weight and standard tolerance ranking at seedling stage under salinity stress induced by NaCl were identified on chromosome 1 using composite interval mapping. Seven major QTLs associated with drought and salinity tolerance were mapped in adjacent of RM212 and RM1287 markers at two growth stages. The major QTLs qGR-1 and qSV-1 were detected under both stress and non-stress conditions showing the stability of these QTLs under diverse environmental conditions. Furthermore, the same locations of the QTLs qSKC-1 and qRL/SL at seedling stage with the QTLs of germination related traits showed the same genetic control of these traits at both germination and seedling stages, associated with drought and salinity tolerance controls by the same genomic regions. Also, the location of the QTLs associated with salinity tolerance were very near to the QTLs associated with drought tolerance which indicated that drought and salinity tolerance in rice controls by pleiotropic or tight linked genes. It seems that the rice breeding for one of these stresses can be successful to the other stress.

This study was conducted to evaluate the response of eight Iranian bean cultivars, Derakhshan, Akhtar, Azna, Naz, Jamaran, Goli, Sayad and Khomein, to root-knot nematode, M. javanica, in the glasshouse condition. A factorial experiment was performed using two factors, bean cultivars and nematode inoculation, in a completely randomized design with four replications. Each pot was filled with pasteurized soil and seven days old bean seedlings were inoculated with 2000 second stage larvae of M. javanica. Plant growth and nematode reproductive factors were measured eight weeks after inoculation. Bean cultivars showed different levels of susceptibility to the nematode. Regarding to growth-related factors, the cultivars Sayad, Azna and Akhtar were significantly less influenced by nematode attack than other cultivars. In case of nematode-reproduction parameters, Khomein, Jamaran and Derakhshan cultivars showed less susceptibility.

Characteristic identification of local and foreign hazelnut cultivars and their hybrids was the purpose of this research. Male parents Gercheh and Gerdoii and female parents Fertile, Pashmineh, Rasmi, Round, Shastak, Negret and Paeezeh with high yield and performance were selected. Fourteen crossing combinations were made and the obtained hybrids were evaluated based on ten morphological traits including vegetative growth, shoot length, shoot diameter, leaf length, leaf width, internode length, petiole length, total chlorophyll, chlorophyll a, and chlorophyll b. The experiment was conducted in a complete randomized design. Analysis of variance indicated that the parents and progenies were significantly different for all examined traits. Fertile × Gercheh and Rasmi × Gercheh progenies exhibited the lowest internode length and Gerdoii, Gercheh and Rasmi × Gerdoii exhibited the highest shoot length. Total chlorophyll, chlorophyll a and chlorophyll b levels were higher in parents than progenies and Rasmi × Gercheh hybrid had the highest chlorophyll a, and chlorophyll b among the hybrids. Cluster analysis classified parents and progenies into four main groups.

Onobrychis genus has more than 69 annual and perennial species in Iran. Onobrychis michauxii is a perennial plant and belongs to Hymenobrychis section of Onobrychis subgenus. In this research 44 populations of sainfoin collected from different locations of Iran were evaluated at Seed and Plant Improvement Institute, Karaj, Iran, using a randomized complete block design with three replications. Analysis of variance on morphological traits data showed significant differences for all traits except calyx tube length, wing width and pod length indicating high genetic diversity among the populations. The highest variation was observed in the flower tube to teeth ratio, while wing length had the lowest variation among the quantitative traits. Using the Shannon index in qualitative traits, flower color and density of florescence had the highest and least diversity respectively. Length of keel showed positive and significant correlation with length of standard. Cluster analysis based on Ward method divided populations into two groups In the light of the results of present study, selection and cross between individuals of Ahar population as the representative of group 1 and Torkamanchay population from group 2 (both from East Azarbaijan) can provide maximum genetic diversity.

The tan spot disease, caused by the fungal wheat pathogen Pyrenophora tritici-repentis, is rapidly spreading in north of Iran due to the high susceptibility of most grown wheat cultivars. The successful use of resistant cultivars depends on sufficient information about the pathogen genetic structure particularly the presence/absence of virulence factors within the fungal populations. The present study was carried out to determine the distribution and frequency of the ToxA and ToxB- producing genes in Iranian fungal population. Wheat samples showing the tan spot symptoms were collected from north of Iran and transferred to laboratory. After fungal isolation, purification and propagation, DNAs from P. tritici-repentis were isolated. The DNA samples were screened using specific primers for detection of ToxA and ToxB genes. The results showed that 86% and 77% of isolates possess ToxA and ToxB genes, respectively, while 64% of isolates possess both virulence factors. Based on these results, most of the tan spot isolates collected from north of Iran contain ToxA and ToxB genes and their distribution in studied isolates were not restricted to specific geographical regions. This study showed that chlorosis and necrosis induced by this pathogen can be attributed to the high frequency of theses genes in the fungal populations..

This study was conducted to identify QTLs controlling yield and yield components in 99 F13 recombinant inbred lines (RILs) derived from barley cross Azumamugi × Kanto Nakate Gold. The parents and inbred lines were evaluated for agronomic characteristics including spike number per m2, kernel number per spike, kernel weight per spike, kernel yield, and 1000 kernels weight. Field trails were conducted as randomized complete block design with two and three replications for 2 planting years, respectively. Significant differences and transgrassive segregants were observed among lines for all of the traits. To identify QTL, composite interval mapping (CIM) was done based on linkage map constructed using 99 RILs and 2 morphological, 2 isozyme, 34 STS and 62 AFLP markers. New QTL controlling spike number/m2 was identified in this population. The QTL explained 10% of the phenotypic variation, was located in the map interval of ABG604-e09m28.8.2 on chromosome 5HL. The QTL detected in the map interval of vrs1-MWG503 on chromosome 2HL could explain most of the phenotypic variation for kernel number per spike, kernel yield and 1000-kernel weight. Most of the phenotypic variation for kernel weight per spike was explained by the QTLs located in the map interval of vrs1-MWG503 and MWG801-vrs1 on chromosome 2H. The results revealed that important QTLs controlling most of the traits were located near by two and six-rowed spike gene vrs1.

In the present study, resistance of 29 potato clones to fusarium dry rot disease was compared with some commercial cultivars and a susceptible check cultivar Lady Roseta. Tubers of the potato clones and cultivars were artificially inocutate with aggressive isolates of Fusarium sambucinum and F. solani and maintained in a growth chamber at 16°C and 95% relative humidity for four weeks. The experiment was in factorial with two factors of Fusarium species and potato clones, using three replications. Disease index, infected area of tubers and sprouting rate were recorded for each treatment after four weeks. Based on the results of experiment, potato clones 397009, 39709713, 39708-10, 397097-2, 397007-16, 397074-3 and cultivar Aria having the lowest disease index (ranging from 168.52 to 228.25) and lowest tuber infected area, were considered as resistant, while clones 396124-97 × 396151-15 and 396151-29 with highest disease index and tuber infected area were susceptible. Fusarium species had an invert effect on tuber sprouting so that susceptible potato clones and cultivars had the least tuber sprouting rate.

Evaluation of the genetic potential of lettuce germplasm by classical methods or using molecular markers is crucial in breeding programs and introduction of new cultivars. Assessment of genetic diversity of Iranian lettuce genotypes collected from different provinces was conducted in laboratory at Seed and Plant Improvement Institute, Karaj. Forty two genotypes of Iranian lettuce with a foreign cultivar were evaluated using 17 RAPD primers. Primers produced total of 807 polymorphic bands. The highest number of polymorphic bands (78 bands) was produced by primer P9 and the lowest number (15 bands) by P6. The size of produced bands of primers varied from 280 to 3000 bp. Jaccard similarity coefficients was calculated for 43 genotypes, that varied from 0 to 0.324. The highest similarity was observed between genotypes no. 13 and 14 (0.324), no. 19 and 20 (0.314) and no. 7and 8 (0.300). Cluster analysis of molecular data, at the similarity level variation 0.25 clustered Iranian lettuces into four groups. Generally, the results of this experiment showed a high genetic diversity in Iranian lettuce genotypes and revealed that RAPD is a useful and effective technique for classification of Iranian lettuces.

In this study, reaction of 62 Iranian commercial bread wheat cultivars was evaluated for resistance to stem rust disease caused by Puccinia graminis f. sp. tritici (Pgt) at seedling and adult plant stages. Seedling tests were carried out with the prevalent stem rust races, TTSTC, TTTTF, TRTFC, TTKSK (Ug99), TTTTC and TKTTC. Adult plant reaction to stem rust was evaluated in Kelardasht research station under natural infection, and in greenhouse by artificial inoculation with race TTKSK (Ug99) at Seed and Plant Improvement Institute, Karaj. The results demonstrated that response to Pgt was significantly different among cultivars. Among 62 cultivars, 39 (63%) were identified without any effective resistance against all tested races, where 13 (21%) were resistant to one or more races but susceptible others, and 10 (16%) cultivars including, Rasool, Falat, Golestan, Atrak, Shiroodi, Dez, Zagros, Bahar, Gonbad and MV17 were susceptible to TTKSK (Ug99) and resistant to others. The latest cultivars demonstrated to carry the resistance gene Sr31.

This study was carried out to assess the genetic diversity among and within twenty Iranian fenugreek landraces (randomly selection of eight single plants from each landrace) using amplified fragment length polymorphism (AFLP) markers. Five selective primers, produced a total of 147 bands within the molecular weights ranging from 50 to 500 base pairs, of which 128(87%) were polymorphic. Polymorphism information content (PIC) scores ranged from 0.79 for Kashan to 0.93 for Broojerd and Khorasan landraces, indicating that these landraces had the least and the most amount of within population genetic diversity, respectively. Analysis of molecular variations (AMOVA) showed that the diversity within landraces accounted for 75% of the total variations and there was suitable genetic diversity within studied landraces. Genetic similarity coefficients between lines ranged from 44% to 94%. The results also showed high efficiency of AFLP markers for investigation of fenugreek genetic diversity.

Jujube (Zizyphus jujube L.) is an important tree with different species and varieties distributed in the central and west Asian regions as well as in Iran. The present study was performed to investigate the genetic diversity in jujube germplasm of Iran, collected from eight provinces grown in a collection garden in south Khorasan province. The genetic diversity was studied based on quantitative characteristics and ISSR and RAPD molecular markers. The results of molecular analysis showed a considerable genetic variation among 32 studied ecotypes. Six efficient primers were selected among 13 ISSR primers e.g. (AC)8YT and (GA) 8A. A total of 84 loci were amplified and 70 (83%) showed proper polymorphism. Among 15 random primers of RAPD markers, more than 80% polymorphism appeared among amplified loci of ecotypes. Phylogenetic analysis using matk gene, indicated existence of at least three different species in Iranian jujube collection. Cluster analysis of quantitative characteristics classified jujube ecotypes into three to six groups. Generally, variation in jujube germplasm could be mainly found in three provinces Mazandaran, Isfahan and South Khorasan, the latter almost covers the total variations.

Characteristics of forty pecan genotypes in Golestan province were evaluated for three years using pecan descriptor. Cluster analysis based on quantitative and qualitative traits of fruit, fruit shape and maturity time, divided genotypes into ten main groups. Factor analysis was employed for defining the determinant factors, and the characteristics constituting each factor. The effective traits were categorized within four factors which accounted 70% of total variance. Within each factor, characters with coefficient values of more than 0.5 were considered significant. Factor analysis revealed that the traits of fruit shape, nut and oil percentage, kernel fresh and dry weight, fruit dimension, length to width ratio and shell thickness were some of the characteristics that constituted the main factors. Based on the obtained results and observation through these three years, six trees (genotypes) G2, G3, G4, G19, G20 and G28 showed better performance than the other genotypes.

Charcoal rot caused by Macrophomina phaseolina is an important disease of soybean in Iran. Effective and reliable techniques are needed to select aggressive isolate of the pathogen and evaluate resistance of soybean genotypes to the pathogen. In the present study, 32 isolates of the pathogen from different oilseed crops were examined in vitro, and So.3 was selected as the most aggressive isolate for resistance evaluation. Resistance of seven soybean genotypes was then evaluated in vitro and greenhouse conditions using toothpick and stem cut inoculation methods. Genotypes differed significantly for pathogenicity index in both inoculation methods. Genotypes Hatcheston, Sari, Hamilton and Katol had lower pathogenicity index compared to the other genotypes. Hacheston with the lowest infection at seedling stage, and L.17 and Williams with the highest infection, were evaluated as the most resistant and susceptible genotypes, respectively.

Late spring frost usually damages flowers and reduces yield of almond trees. Due to natural sexual reproduction, in most of almond orchards of Qazvin province, Iran, which have been established through seedling propagation, a vast genetic variation has been occurred. This situation has been provided many possibilities to study different traits of native almond genotypes, to select superior genotypes especially those with late flowering and cold tolerance. In the present study, flowering characteristics of twelve superior almond genotypes (G1-G12) which had been selected in the first phase of study were evaluated based on descriptor list for almond (IBPGRI). Results of assessments showed that these genotypes were significantly different for the majority of the traits especially those related to flowering. Cluster analysis of data divided genotype into different groups of late flower to normal. Difference between beginning of flowering in genotypes was recorded 14 days. There were also significant correlations (positive or negative) between different traits.