سیما دامیار

During the last two decades, valuable apple genetic resources have been collected and planted in the collection of native apple in Karaj, Iran. In present study, the phenological and pomological characteristics of 15 apple promising genotypes with cv. Golden Delicious and cv. Gala, as control cultivars were evaluated in Kamalshahr field station, Karaj, Iran, in 2012 and 2013. Considerable diversity for phenological and morphological traits was observed among apple genotypes. T-R1 and SH-R genotypes were the earliest flowering and B-K-KH was the latest flowering genotype. Apple promising genotypes showed overlapping for flowering time and grouped into early flowering, medium flowering and late flowering genotypes. T5 genotype had the lowest before harvest fruit drop, while KH-1 genotype had the highest fruit drop. SSB genotype had the highest fruit length, fruit diameter, fruit weight and flesh firmness, and in contrary GO-N3 genotype had the lowest values for these traits. M-N10 genotype was superior for fruit aroma, fruit taste and texture as well as overall fruit acceptability. The sweetest fruit belonged to "Golden Delicious" and the most sour fruit related to genotype T5. H1-SH genotype as well as GO-N3 were the earliest ripening cultivars. According to the results of this study, M-N10, M-N8 and H1-SH genotypes were superior in comparison with other apple promising genotypes for the overall acceptability of pomological and organoleptic characteristics. Finally, the M-N10, M-N8 and H1-SH genotypes were released in 2021 as new early and medium ripening apple cultivars with the names of Nima, Zagros and Shamin, respectively.

Diplodia seriata is the causal agent of apple limb and trunk cankers as well as fruit black rot. Disease was detected in the Iranian apple collection located at horticultural research station of Kamal-shahr, Karaj. Fourteen apple promising genotypes and two commercial cultivars (Golden Delicious and Fuji) were tested in the field and laboratory for their relative susceptibility to the pathogen, during 2016-2017. The fruits were inoculated in the field at 2 to 3 weeks before harvest with fungal mycelia from 11-day-old cultures of PDA medium. In the laboratory, detached fruits were inoculated similarly. Genotypes were classified for susceptibility to the fungus by determining disease severity of attached fruits in the field based on lesion expansion (mm/degree-day), and on detached inoculated fruits in laboratory according to the mean lesion diameter, both 5 days after inoculation. Based on the laboratory and field data, Iranian genotypes were classified into three relative susceptibility groups: most susceptible: TR-1, SSB, and H1-SH; moderately susceptible: MD-N2, GO-N3, B-K-KH, DO-P-SH, MN8, T5 and Golden Delicious; least susceptible: SBA, MN10, S-O-G, KH2, ME6 and Fuji. There was a negative correlation between disease severity and flesh firmness, but total solid soluble (TSS) and les

Through this investigation 18 promising local apple genotypes along with Gala, Fuji, Red Delicious and Golden Delicious cultivars were evaluated for tolerance to fungal cankers in Kamalshahr horticultural research station, Karaj, Iran, during 2015 and 2016 growing seasons. Preliminary field assessment confirmed the presence of Cytospora. and Neofusicoccum in infected trees. The results showed that the relative susceptibility of genotypes to cytospora chanker was different. H1-SH and T51 genotypes with the average infection score of three were identified as susceptible, B-K-KH together with Fuji cultivar were moderately-susceptible, and SBA genotype and cv. Golden Delicious were identified as low susceptible. Artificial inoculation of Neofusicoccum isolates on dormant excised apple twigs confirmed the pathogenicity of isolates and showed different responses of genotypes to pathogen. Under field conditions, the infection score for sooty canker ranged from zero to three (in MD-N2 genotype). GO-N3, ME6, B-K-KH and SBA genotypes as well as cv. Fuji, cv. Red Delicious and cv. Golden Delicious were grouped as moderately susceptible. Simultaneous infection to both fungal cankers observed on five promising genotypes; T51, SBA, S-O-G, H1-SH and B-K-KH, as well as cv. Golden Delicious and cv. Fuji. It can be concluded that there are invaluable resistance sources among promising local apple genotypes, under natural infection, to be selected and used in apple breeding programs.

Fire blight disease caused by Erwinia amylovora is one of the most important diseases of pome fruits worldwide. In this research, the resistance of 24 selected apple genotypes was evaluated using a mixture of four Erwinia amylovora strains collected from Alborz, Kordestan, West Azarbijan and Khorassan Razavi. The plant material was grafted on apple seedlings in 2013. The grafted plants were transferred to the greenhouse and evaluated for fire blight resistance in spring 2015 and 2016- using shoot-tip inoculation method. Five weeks after inoculation, the blight severity were scored and recorded based on the progression of necrotic area on shoots. Based on the results, the fire blight severity was higher in 2015 than 2016 (24.54% and 17.68%, respectively). The results also indicated that seedling (SSB) and Shemirani Tabestaneh (SH2) genotypes were susceptible and three genotypes including Bigi Kenar Roundkhameh (B-K-Kh), Torbati (T-R1) and Kouzehei Salmasi (Go-Sa) were resistant. Genotypes were grouped into four classes including; susceptible (4.35%), moderately susceptible (13.04%), moderately resistant (17.39%) and resistant (65.52%), and there was no highly susceptible genotype. The results showed that most of the local apple genotypes examined in this research were resistant to fibre blight disease.

Neofusicoccum mangiferae is the causal agent of branch wilt, blossom blight, canker and dieback on a variety of fruit trees such as almond, hazelnut, apricot, peach, citrus, grape and apple. Cracking and peeling of thin outer layer of bark and exposing black sooty mass of spores is a characteristic feature of disease. Pathogen causes gradual declining and sometimes complete death of trees. The fungus infects the hosts through wounds, created by pruning, frost damage, drought stress, or bark cracks caused by sunburn and develops under hot and sunny weather in summer. Good sanitation, fertilization of trees, adequate irrigation, appropriate pest control, preventing wounds, and avoiding unnecessary pruning are the methods for disease management.

Fireblight disease caused by Erwinia amylovora is a serious disease of apples worldwide. In this research, resistance of 30 apple superior local genotypes and introduced cultivars was evaluated to fire blight using shoot-tip-inoculation method in glasshouse condition. Repeatability of the inocultion method was also investigated by repeating the experiments for two years (2012 and 2013). The inoculum comprised of four E. amylovora strains including EO1, E4, En and Ek originated from Kordestan, Alborz, Khorasan Razavi and West Azarbijan provinces. Based on the results, different cultivars and genotypes exhibited different resistance level to fire blight disease. In both years, Boshghabi was the most susceptible and Ferdovs and Delicious Mari the most resistant genotypes. Analysis of mean fire blight severity revealed that the first-year data was directly correlated with the second-year (R = 0.54), indicating relative accurence of shoot-tip-inoculation method for fire blight resistance assessment. Collectively, 6.7% of Iranian genotypes were rated as highly susceptible, 46.7% susceptible, 26.7% moderately susceptible, 13% moderately resistant and 6.7% resistant, indicating hight fireblight susceptibility in Iranian apple germplasm.

In order to study fruit quality changes in apple cultivar Gala, related to ripening stage and storage time, an experiment was conducted in a split plot arrangement in Randomized Complete Block Design with four replicationsin the area of Damavand– Jaban for three years. Five levels of sampling times in storage were assigned to main plots, and three levels of harvesting times were randomized in sub plots. Flowering time was recorded for six selected trees. Fruit was harvested during ripening process, every week, based on the starch index (1-5). The samples were tested for total soluble solids content (TSS), titratable acidity (TA), weight decrease, fruit firmness, flavor and acceptability. Harvested fruits were stored in storage under 0 ± 1°C temperature and 85 ± 5% relative humidity, for five months. The optimal fruit quality was achieved when the fruits harvested in 110 days after full-blooming with 2.0-2.5 starch index.

Study of morphological traits of red fleshed apples is a critical step to improve the quality and commercializing of them. In order to study genetic diversity of Iranian red fleshed apples، a total of 17 morphological characteristics were assessed for eight genotypes of red- fleshed (‘Haji Qermez’، ‘Gousht Qermez’، ‘Shahroud-10’، ‘Arous Gousht Qermz’، ‘B. 9’، ‘Qazvin 1، 2، 3’) and 12 Iranian and foreign commercial cultivars (‘Shafei’، ‘Golab Kohanz’، ‘Jonathan’، ‘Golden Delicious’، ‘Granny Smith’، ‘Soltani Shabestar’، ‘Fuji’، ‘Red Delicious’، ‘Heydar Zadeh’، ‘Golab Sahneh’، ‘Gala’، and ‘Shafi Abadi’). Dendrogram resulting cluster analysis of the data classified all genotypes into 7 groups. All Iranian and foreign cultivars were located in distinct groups. The results showed that Iranian red fleshed apples were different in their flesh color. This research can be very useful for introducing theses cultivars to market or using in breeding programs.

Recently، red-fleshed apple genotypes have been widely studied due to their high antioxidant level and good marketing traits. In the present study، six red-fleshed apple genotypes planted in Kamalshar Research Station، Karaj، Iran and three genotypes collected from Shahrood were studied for morphological، phenological، pomological، physicochemical traits and organoleptic characteristics during 2010 and 2011. Based on the results، genotype GH-R had the highest and H-GH3 the lowest tree height (425 and 305 cm، respectively). The highest trunk and scaffold cross areas were also observed in these genotypes. Regarding phenological traits، the longest flowering period (20-22 days) was observed in genotypes B-R and GH-R. Genotype T3 had the highest flower diameter (4. 9 cm). The highest fruit weight، length and diameter was observed in genotype SH-10 (89. 06 g، 5. 33 cm and 6. 18 cm، respectively) and the lowest in B3 (19. 49 g، 3. 12 cm and 2. 60 cm، respectively). The highest fruit firmness was detected in genotype B3 (6. 22 kgcm-2) and the lowest in H-GH (3. 11 kgcm-2). Except SH-10 which had conical fruits، other genotypes had spherical fruits. At ripening stage، genotypes B3، B-R and GH-R had dark red flesh، while in other genotypes، flesh color was pink or red observed only around carpel. Genotypes B-R and GH-R had favorable taste and acceptability، therefore could be used as table fruit or for processing.

Collection and evaluation of germplasms play an important role in fruit tree breeding programs and different molecular markers have been used for this purpose. RAPD marker is one of the most common markers to identify different apple genotypes and varieties. In this study, the genetic diversity of 23 indigenous apple genotypes collected from Azerbaijan, Central Alborz and Central Zagros regions of Iran was evaluated by 11 RAPD primers serie TIB MOLBIOL and commercial cultivar of Granny Smith was consdered as the control. Data were analyzed using NTSYS software, dendrogram was drawn based on UPGMA results and DICE similarity index was used for measuring genetic similarities. Average number of bands was 10.27 for each primer. In general, samples of each region were separate from other regions and were classified in different clusters. However, some samples were placed in the cluster of other regions that it could be due to genotype transition among areas in the past tense. High polymorphism rates were obtained (68.62%). Based on the results, similarity of samples ranged from 0.378 to 0.723. There was high genetic difference among apple genotypes collected from the studied areas, but low difference was observed among samples of each region. In conclusion, investigation of genetic variation indicated that RAPD marker is suitable approach to determine polymorphic loci and to estimate the genetic distance among apple genotypes and cultivars.

Research was carried out in 2007 on 7 native summer-ripening apple cultivars grown inKamal Abad Karaj Research Station. The 16 year-old plants were grafted onto seedrootstocks. The cultivars were Ghandak-e-Kashan, Golab-e-Isfahan, Golab-e-Kohanz,Mashad, Assali, Ghermez-e-Rezaieh and a new cultivar--Koli-e-Mahallat (syn. ESCR). Theaim of the study was to identify changes in qualitative and quantitative traits occurring during cold storage of summer-ripening apples to determine their genetic potential. The fruits were harvested in two stages. The period of cold storage was predetermined to minimize cold storage time for early cultivars and was set at 4, 8, and 16 weeks based on ripening class. The testing intervals were weekly, bi-weekly and 4-weekly testing, respectively. The temperature and relative humidity of the cold storage room were fixed at 0° ± 0.5° C and 80% ± 10%, respectively. Physical and biochemical traits under investigation included weight, firmness, total soluble solids (TSS), titrable acids (TA), pH and flavor index (defined as the ratio of TSS/TA). The results showed that cultivar and harvest time had significant differences. The least loss of fruit weight was observed in Koli-e-Mahallat at the end of cold storage of the first harvest samples. However, for the second harvest, it was recorded in all the cultivars except Golab-e-Isfahan. The greatest firmness registered in Golab-e-Isfahan at the end of cold storage and in Ghandak-e-Kashan and Ghermez-e-Rezaieh for the second harvest. At the end of cold storage, the highest TSS (>12%) was recorded for Golab-e-Kohanz; highest pH (<4) and TA values (>40%) for Mashad. Assali and Golab-e-Kohanz had the highest flavor index (TSS/TA>60%) at the end of cold storage for the first harvest. Koli-e-Mahallat, Assali, Golab-e-Isfahan and Golab-e-Kohanz had the highest values for the second harvest.

Identification of plant cultivars and rootstocks, requires accurate andreproducible methods which not affected by environmental conditions. In thisresearch, efficacy of SSR markers in identification of some apple genotypes androotstocks was studied. For this purpose, 5 pairs of SSR markers were applied foridentification of 24 and 5 Iranian and foreign apple genotypes and rootstocks,respectively. According to the results, 52 polymorphic alleles were proliferated in 5microsatellite loci (mean 10.4 alleles per locus) and polymorphism informationcontent (PIC) was 80%. The markers produced specific DNA bands in "Lobnani(tabestane)", "Golab (Damavand)", "Golab (Isfahan)", "Malyer 8" and "Malayer 9"genotypes and specific band patterns in "Bahare arak", "Shemirani", "Lobnani(tabestane) ", "Damavand B1", "Golabn (rasmi) ", "Golab (damavnd) ", "Golab(sahne) ", "Malayer 8", "Malayer 6", "Malayer 9", "Shafiabadi (chalus) and "Golab(paize) ". In rootstocks, 12 specific and reproducible alleles were identified. Theresults indicate the high efficacy of SSR markers for apple cultivar and rootstockidentification.

Relative resistance of 58 local apple genotypes to Erwinia amylovora (Burrill.) Winslow et al., the causal agent of fire blight was studied. Bacterial strains were collected from pome fruit orchards of Orumieh, Karaj, Mashhad, Shahrud, Qazvin and Sanandaj cities and identified using phenotypical and molecular tests. A mixture of seven strains were used as inoculum. Evaluation was performed using shoot tip inoculation method nuder glasshouse condition on one-year old seedlings grafted onto M26 rootstocks and blight severity was scored six weeks after inoculation. Based on the results, 5% of genotypes were rated as resistant, 17% moderately resistant, 18% moderately susceptible, 28% susceptible and 32% highly susceptible. Based on these results, it is concluded that local apple germplasm is relatively susceptible to fire blight.

An experiment was conducted to evaluate relative resistance to P. cactorum, the casual agent of apple crown rot, in eleven apple rootstocks. The experiment was in factorial (with apple rootstocks and year factors) on the basis of completely randomized design with three replications. Each plot consisted of four young plants. All rootstocks excluding Morabbaei, were propagated vegetatively. One year old rootstocks were evaluated in pots containing soil inoculated artificially with inoculum of P. cactorum. Disease response of the rootstocks was assessed three months after inoculation based on canker length (cm), crown girdling (%), mortality (%) and mean canker area (cm2). The analysis of variance on pooled data showed that effect of rootstock on measured characterestics was significant at 1% probability level. MM106 rootstock was highly susceptible (mean canker area: 4.72 cm2, crown girdling: 89.33%, canker length: 5.28cm and mortality (%): 83.33%). M9, Azayesh and CK1 rootstocks were resistant and Morabbaei and MM111 rootstocks were moderately susceptible compared to the highly susceptible rootstock.. Gami almasi and CK2 rootstocks were moderately resistant and M26, M27 and B9 rootstocks showed relatively tolerance responces to P. cactorum. Interaction between year and rootstock was not significant.