نشریه نهال و بذر
سال سی‌ام شماره 2 (تابستان 1393)

Fire blight is an important disease of pome fruits including pears, and cultivation of resistance cultivars and rootstocks are one of the most effective methods for disease control. In this study, resistance of OHF87 and Pyrodwarf semi-dwarfing pear rootstocks were compared with two control cultivars, Dar Gazi (resistant) and Bartlett (susceptible) in greenhouse and in vitro conditions. Following propagation of pear rootstocks, they were inoculated with a mixture of Ea273, K1 and Z2 strains of the pathogen (Erwinia amylovora) and progress of the disease were evaluated during 6 and 14 days after inoculation in vitro and greenhouse conditions, respectively. Greenhouse evaluation results demonstrated most resistance level at Dar Gazi cultivar, followed by OHF87 and Pyrodwarf rootstocks and Bartlett. In vitro evaluation results also confirmed the greenhouse ranking of tested pears. Indices of varietal susceptibility and necrosis progress rate were used in greenhouse evaluations, while in vitro conditions necrosis progress rate was the solitary effective index for disease evaluation. Finally, in a complementary in vitro test, evaluation of new pear rootstocks with the same control cultivars showed a classification of resistance, from OHF69 > OHF87 > Dar Gazi > OHF333 > Pyrodwarf > Barttlet > OHF40 > Fox11. Based on the results, three OHF69, OHF87 and OHF333 demonstrated high levels of disease resistance, while for propagation and extension of OHF40 roots tocl, more investigation should be carried out.

Iran is a rich source of high diversity in sour cherry trees. In the direction of breeding programs of sour cherry, this study was carried out with the aim of evaluating and comparing the genetic variability of some selected Iranian sour cherry genotypes with foreign commercial cultivars and better recognizing of their characteristics in order to achieve proper rootstocks and cultivars. Fifty three qualitative and quantitative characteristics related to vegetative sections of tree, flower, leaf and fruit of these genotypes were investigated during 2011 and 2012. The results showed that genotype had significant effect on the studied characteristics and there were significant differences among genotypes in terms of these characteristics. Principle component analysis located the studied characters in five components that explained 81.32% of the total variability observed. Cluster analysis divided genotypes into three clusters in which selected Iranian sour cherry genotypes were separated from foreign cultivars. According to the results, genotypes KaThLa3Ge23, KaTaJo2Ge9 and KaThLaSSGe21 had better growth properties than other genotypes and were superior in terms of properties such as high vigor, yield, fruit weight and redness than foreign cultivars. Therefore, these genotypes can be considered as promising genotypes for further evaluations of sour cherry breeding programs.

To evaluate seed yield, yield components and tolerance to drought stress in 17 spring canola genotypes, two separate experiments were conducted in a randomized complete block design with three replications in two cropping seasons 2008-2010. Irrigation was applied in non stress experiment from planting to physiologic ripening, based on 50 percent and in stress experiment, based on 80 percent depletion of available soil water. Results of combined analysis of variance in two environments showed significant differences among genotypes for seed yield and drought stress indices. Irrigation in 80 percent depletion of available soil water significanty decreased seed yield and yield related traits. In non stressed condition, seed yield, of genotypes 15/1GOL×19H, 39/2FUS×RC, Zabol-6, SG2-87182 and 13/1RG×19H were 3147, 2838, 2831, 2789 and 2779 kgha-1 respectively and in stressed condition genotypes 13/RG×19H, 15/1GOL×19H, SG1-87182 and Zabol-15 with 2596, 2218, 2110 and 2077 kgha-1 produced higher seed yield. Genotypes 15/1GOL×19H, 13/1RG×19 H, and Zabol-6 with the highest seed yield and values of STI, GMP and MP indices were determined as tolerant genotypes to drought stress. Biplot graph presented based on principal components indicate that STI, GMP and MP indices had the highest correlation coefficients with each other and tolerant genotypes were located closed to the tolerant indices. These indices can be used as the best criteria for evaluation and identification of tolerant canola genotypes in breeding programs.

Fennel is a perennial and aromatic herb and its essential oil and extract is extensively used in pharmaceutical, food, and cosmetics industries. In order to compare seed yield and yield components in twelve genotypes of fennel (ten native populations and two foreign cultivars 11486 and P11- 820065), an experiment was conducted during 2004-2006 in Isfahan. The experiment was on the basis of randomized complete block design with three replications. Native populations were collected from Bushehr, Oromieh, Shiraz, Yazd, Isfahan, Mashhad, Lorestan and Hamedan. Different morphological, physiological, seed yield and percentage of essential oil of genotypes were recorded only in the second and third years as due to cold damage, data on traits could not be recorded in the first year. The results showed a significant difference for all traits among genotypes. The highest and the lowest seed yield were obtained from P11-820065 (561 gm-2) and Ebne Sina (201.22 gm-2), respectively. The experimental years had a significant effect on seed yield and essential oil percentage. Foreign cultivars had the highest plant height, seed yield and 1000 seed weight due to longer vegetative and reproductive periods. A positive correlation was obtained between seed yield and weight of 1000 seeds, days to rippning and number of umbels. Culivar P11-820065 can be recommended as a genotype with high seed yield and high essential oil for cultivation in the same climate as the experimental region.

To evaluate characteristics of wheat genotypes in salinity condition and select the best genotypes, 114 genotypes of spring bread wheat were evaluated in two environments, non-saline (Gorgan station) and saline (Mazrae Nemoneh) during 2008-09 growing season. Cultivars Kavir, Kohdasht and Morvarid and line N-80-19 were used as control, in six RCBD designs with three replications in 2009. Results of cluster analysis showed that genotypes no. 12 and 38 had the highest yield in saline and non-saline conditions. The selected genotypes had plant height of 83-86 cm, peduncle length of 40% of plant height, 1000 grain weight of 48-54 g, and time to heading of 104 days. Thousand grain weight and grain weight per spike had the highest and day to maturity had the lowest diversity. Principal component analysis showed that plant height, 1000 grain weight and yield based on three selected components, had high impact on selection of genotypes.Results of cluster analysis showed that genotypes with high yield in saline and non-saline conditions, plant height and spike length and weight were clustered in group one. Based on these results, it is recommended that for introduction of new genotypes for salt affected land of Golestan, selection for on farm experiments should be done in advance genotypes under saline condition and the best genotype should have high yield under saline and non saline conditions.

To investigate the genetic diversity among clones of Zard and Rowghani olive cultivars, 29 clones of these cultivars were studied. After assessing 16 quantitative and 19 qualitative characteristics, clones were genetically studied using 18 mocrosatellite markers. In total, 52 alleles were amplified from which 46 alleles were polymorphic. The average number of alleles per locus was 2.944, varied in the range of 2-6. The highest and lowest observed and expected heterozygosity were obtained in the range of 0-0.931 and 0.128-0.781, respectively. The average polymorphism information content (PIC) were 0.366 that the highest value was in locus GAPU89 and the lowest in locus UDO99-043 (0.711- 0.120, respectively). The PIC values showed a direct relation with number of alleles and amount of variation per locus. Cluster analysis using UPGMA method and Jaccard similarity coefficient with value of 54% placed all clones in to five groups. Analysis of molecular variance showed significant variation within and among Zard and Rowghani cultivars (58 and 42%, respectively). In general, the results of this study showed that there was a genetic diversity among clones of Zard and Rowghani cultivars that could be due to the presence of true differences or problems due to homonyms or mislabeling of clones. Since these cultivars are the most important olive cultivars, knowing the genetic differences and detailed morphological studies can be useful for identification of clones of these two cultivars in the early stage of growing in the nurseries, breeding purposes and clonal selection.

Due to complexity of plant responces to the pathogens, recognition of resistance systems including behaviour of PR genes is an important aspect in this interaction. This research was conducted to isolate and evaluate diversity of some PR genes in genotypes of apple (Malus×domestica), pear (Pyrus communis), willow-leaved pear (P. salicifolia) and quince (Cydonia oblonga) species. Primer design was achieved on PR1a, PR3-Ch1, PR3-Ch2, PR3-Ch3, PR3-Ch5, PR5 and PR8 genes using sequences of genetically related dicotyledon and DNA extraction performed using a CTAB-SDS combine method. Number of evaluated apple, pear, willow-leaved pear and quince genotypes were 7, 7, 1 and 12, respectively. Following optimization of the thermal profile and concentration of the PCR component reaction, significant transferibility of PR genes primers were observed among tested pome species. According to the homology search, PR1a, PR3-Ch1, PR3-Ch3, PR3-Ch5, PR5 and PR8 genes were isolated and reported in some indigenous or exogenous apple cultivars, as well as in pear and quince cultivars. in addition, PR3-Ch4 gene was isolated in apple and pear and deposited in data bank. Comparison of the genetic diversity of the isolated genes by using DNA sequencing method indicated high level of homology despite existance of some minor point mutations in nucleotid sequences of various pome species.

Eight tomato cultivars (GH1, GH12, Ajeet, Karina, Cluster 5, Manisha, Tolstoi and Dartom native) were screened for resistance against the root-knot nematode, Meloidogyne javanica, under controlled environmental conditions. In greenhouse experiment, tomato seedlings were inoculated with two J2s/g soil. Eight weeks after inoculation, the reactions of the cultivars were evaluated. Based on the nematode reproduction factors, the cultivars GH12 and Ajeet evaluated as moderately resistant and GH1 and Manisha as tolerant, whereas the other cultivars were susceptible to M. javanica. In molecular studies, eight pair of microsatellite (SSR) markers were used to find markers linked to resistance to M. javanica. Second allele of the primer Tom 55-56 was the only allele in moderately resistant cultivars, whereas the second allele of Tom 47-48 found only in susceptible cultivars. These alleles showed significant correlation with number of galls produced by the nematode. The correlation coeffivients of Tom 47-48 with susceptibility and Tom 55-56 with resistance were 0.732 and -0.732, respectively. The other alleles were not related to susceptibility or resistance.

Almost in all parts of Iran, fenugreek has been cultivated as a vegetable and medicinal crop since long times ago, but there are less information about its heritability and breeding. Twenty fenugreek landraces from different parts of Iran were evaluated under normal and limited irrigation conditions at Maragheh dryland agricultural research station during 2008-2009 cropping season using a randomized complete block design with four replications. Results of combined analysis of variance for different morphological traits showed significant differences among landraces for all traits except for harvest index under limited irrigation and in number of pods per plant, number of seeds per plant and dry biomass under normal irrigation conditions. Results of cluster analysis(Ward method) divided the landraces into four different groups. The highest genotypic variances was observed in growth habit, growth vigor, thousand seed weight and seed yield per plant under both conditions. Thousand seed weight, days to flowering and plant growth type under both conditions had the highest heritability indicated that, selection for these traits will be efficient in fenugreek breeding programs under limited and non limited irrigation conditions.

The causal agent of spot blotch is the fungus Cochliobolus sativus which is one of the most important wheat pathogens worldwide. Among several wheat samples showing typical spot blotch symptoms collected from different regions of north of Iran, eight samples were selected as representative and the fungal pathogens were subsequently isolated and characterized using morphological, pathological and molecular approaches. Morphological characteristics of these isolates were determined using illustrated fungal keys demonstrating that the observed symptoms were due to wheat infection to C. sativus. Pathogenicity tests showed that isolated C. sativus were able to cause typical spot blotch symptoms on Bolani as the susceptible cultivar. Sequencing results revealed that ITS regions of Iranian isolates were identical to that of the C. sativus reference isolate. Phylogenic relationships of Cochliobolus spp. were investigated using different methods including genetic distance, maximum parsimony and maximum likelihood showing that all phylogenetic tree patterns were similar and Iranian isolates were clustered with the C. sativus reference isolate. Cochliobolus spp. were clustered in two major groups containing some minor groups. Estimated genetic distance showed that C. eleusines is the most related species to C. sativus, while C. kusanoi and C. austaliensis were the most distanced species to C. sativus. This study revealed that spot blotch is a widespread disease in the north of Iran and, therefore, to control the increasing spread of the disease, the resistance for this disease should be considered in breeding programs in this region.

Morphological traits can be used as signs for identification of plant growth stages and selection indices. Development of linkage maps is one of the DNA markers application uses in QTL analysis for identification of chromosome regions of controlling genes of quantitative traits. In this research, from the cross between Mousatarom and 304 cultivars, 193 single plants of F2 were harvested separately and used for planting 193 F2:3 families accompanied to the parents. This experiment was conducted in augmented design with three control treatments named as Lenjan- Askari, 304 and Domsiah Nourabad-Mamasni local cultivar in six replications (blocks) which F2:3 families were randomly cultivated within the blocks. The studied Traits were seedling height, plant height, culm length, panicle length, length and width of penultimate leaf, length and width of brown rice kernel, rice shape and tillering number. Panicle length and tiller number had low heritability (< 0.2), leaf length and width had medium heritability (0.2-0.5), plant height, seedling height and culm length had high heritability (0.5-0.8), and brown rice characteristics had very high (> 0.8) narrowsense heritability. Eighty one primers related to microsatellite marker, were selected based on SSR maps, and based on the results, two QTLs for plantlet height, one QTL for panicle length, two QTLs for tillering number, three QTLs for leaf width, two QTLs for seed length, two QTL for seed width and two QTLs for seed shape were identified.

The area of walnut orchards has been has increased rapidly in Iran, using seedling rootstocks in recent years. With the goal of releasing new walnut cultivar(s), in the present research twenty one walnut genotypes preselected based on their regular bearing, high productivity and spring frost resistance were compared with three foreign walnut cultivars Hartley, Chandler and Pedro and two pollinizer cultivars Franquette and Ronde de Montignac as control, during 2010 and 2011. Results showed that among cultivars and genotypes, nut weight varied from 7 g in Ronde de Montignac to 13.6 g in genotype H2/11. The kernel weight also varied from 3.17 g in the Ronde de Montignac to 7.22 g in the genotype H2/11. The kernel percentage varied from 41.5% in cultivar Pedro to 58% in genotypes H2/12. For the kernel yield, the genotype H2/12 with 3133 kgha-1 was most productive. Meanwhile, the highest nut yield belonged to genotype H2/12 with 5369 kgha-1. Based on the results the genotypes H1/1, H2/1, H1/7, H2/12 and B10 were selected as promising genotypes for further studies in different regions.

To investigate variation and detect the genomic regions controlling quality and quantity of malt extract in barely, a study was conducted using a set of 72 double haploid barley lines as well as their parents (Steptoe and Morex) in RCBD with two replications during the cropping season 2011-12. Different characteristics including germination energy, total percentage of germination, seed dormancy, seed protein, seed malt extract, seed hull, hectoliter weight, seed plumpness, plant height, days to heading, spike length, seeds per spike, peduncle length, one thousand kernels weight, grain yield and harvest index were measured. QTL analysis was done using composite interval mapping (CIM) method for each trait by means of two environments; and multiple interval mapping (MIM) method was exploited for assessment of significant interactions between loci, additive × additive epistasis and testing major effects of detected QTLs at a multiple regression model. For most of traits, transgressive segregation was observed in both positive and negative directions. A total total of forty-nine QTLs with LOD ≥ 2.5 (LR ≥11.5) were identified. Explained genetic variance by these QTLs varied from 27.74 to 81.42% and maximum LOD for the QTL controlling seed plumpness was obtained on chromosome 3H (Qplum3H) with a LOD = 9.08. The largest single QTLs belonging to the quantity and quality of barley grains malt were located on chromosomes 1H, 2H, 3H, 4H and 7H. Seven additive × additive epistatic effects between identified QTLs were significant. The results revealed that water deficit compared with the location, had a significant role in the manifestation of malt quality traits. Meanwhile, in the studied haploids and their parents great variation was observed in terms of quantity and quality characteristics of barley malt. This variation can be exploited for different breeding purposes. In addition, identified stable and clustered QTLs could be used for qualitative and quantitative traits of barley malt in marker assisted selection (MAS). However, some detected markers can be identified as an informative marker for selection and increment of the concentration in the final malt extract and malt performance.

Determination of genetic diversity level and relationships is the first step in exploration of crop landraces in breeding programs. In the present study, genetic diversity and relationships of 144 barley genotypes consisted of 119 landraces and 25 breeding lines were analyzed using 32 polymorphic SSR primer pairs. In total, 143 alleles with range of 2 to 12 alleles were amplified in the studied genotypes. The mean number of alleles per locus was 3.45 for breeding lines, 4.41 for landraces, and 4.47 for all the genotypes and the mean polymorphic information content (PIC) scores were 0.44, 0.53 and 0.53 for breeding lines, landraces, and all the genotypes, respectively. Nei gene diversity or expected heterozygosity ranged from 0.22 to 0.87, with an average of 0.59. Grouping of genotypes using Minimum Evolution method algorithm and Kimura 2-parameter model assigned the genotypes into eight clusters. The first three vectors in principal component analysis explained 71.77% of total molecular changes among genotypes. Grouping of genotypes using the first two vectors were consistent cluster analysis. The results revealed that SSR markers are efficient tools for genetic diversity analysis in barley germplasm collections as well as for collection and preservation strategies in gene bank.