نشریه نهال و بذر
سال بیست و دوم شماره 4 (پاییز 1385)

Prunus cerasus L. is one of the principal rootstocks used for sweet and sour cherries in Iran and world widely. This study was conducted at Khorasan Agricultural and Natural Resources Research Center to investigate the genetic variability in sour cherry populations collected from three provinces of Iran, and identification of sour cherry dwarf genotypes for cherries. Morphological characters of ten sour cherry populations were studied. One-way analysis of variance, performed for determination of genetic diversity of different regions populations indicated significant differences for most traits. Factor analysis detected four factors. In the first factor, crown height, size index, crown width, trunk cross sectional area, stone weight and crown volume had highest factor loading. Internode length was the second most important factor. In the third factor, leaf area and in the fourth factor, bark to wood ratio and first branching were important. These factors contained 81.49 percent of total variance. Correlation coefficients showed significant correlation between tree vigor, crown width, crown volume, size index, trunk cross sectional area, internode length, stone weight and bark to wood ratio. Sour cherry seedlings showed high variability in vigor. Based on the size index, sour cherry seedlings were classified into four groups of very dwarf, dwarf, semi dwarf and standard.

Forty four dryland barley advanced lines were tested at adult plant and seedling stages to determine their responses to barley powdery mildew in two locations, Karaj and Gorgan, in a RCDB design with three replications for two years 2001-2003. Field responses of the lines were assessed by Saari and Prescott method. For greenhouse experiment, isolates of barley powdery mildew collected from Karaj and Gorgan were transferred to the greenhouse. After multiplication of each isolate, the lines were inoculated with them separately. Seedling infection types were recorded based on Mains, and Dietz. The results showed that at adult plant stage in Gorgan, four lines were resistant and in Karaj, six lines were immune and four lines were resistant. The most susceptible line was T-2 (2R)//Lignee131/Arabi Abiad. Lines ICB-111028, ICB-111838, Obruk-86, Wieselburger/Ahor, Alpha//Sul/Nacta/3/80-5001 ICB, ICB1, ICB-100974/Acton and 4679/105//Yea132TH/3/Tipper showed resistance response in both locations. At seedling stage in the greenhouse, with Karaj isolate, only two lines were resistant and the remainings were susceptible. With Gorgan isolate, 15 lines were resistant, and 29 lines were susceptible. At seedling stage, only line Wieselburger/Ahor was resistant to isolates of both locations.

The fragrance and flavour is substantially important in rice commerce. Thereby, it is rational to consider the different aspects of this trait attentively. Hence, an investigation was conducted to study the allelic status of fragrance locus in aromatic rice cultivars Sang-tarom, Basmati 370 and Della. The F2 populations of three crosses among these cultivars were molecularly tested by random amplified polymorphic DNA marker OPAG-08 that is closely linked to rice fragrance gene and in PCR amplifies the 800 bp amplicon in aromatic cultivars, to study the inheritance of fragrance in F2 populations. Based on molecular results, the 800 bp amplicon was produced in 75% of F2 offspring suggesting that at least one identical allele exists in parental cultivars. In the other hand, the amplicon was not produced in the rest of F 2 offspring that reveals the presence of different allele(s) in that locus in parental cultivars. Therefore, regarding the segregation in F2 population, it seems that fragrance locus in these cultivars is controlled by different alleles leading to segregation in their F2 populations.

During 2001-2003,the reactions of 23 wheat advanced lines and commercial cultivars were evaluated in the field trials against important fungal diseases, yellow rust (Puccinia striiformis), septoria leaf blotch, (Septoria tritici) and common crown and root rot (Bipolaris sorokiniana and Fusarium culmorum). Results indicated that lines M-78-1, M78-12, M-78-13, M-78-14, M-78-19 and cv. Shiraz were moderately resistant and lines M-78-5, M-78-6, M-78-15, M-78-17 and cvs. Darab 2 and Roshan were moderately susceptible to yellow rust. The rest were susceptible. These scores were different from those previously recorded for these lines and cultivars. These changes seem to be due to the appearance of the new race, 166E134A+. In case of septoria leaf blotch, most genotypes were susceptible except line M-78-6 which was moderately susceptible. In a field trial, this line produced the highest yield and 1000 kernel weight under high incidence of both diseases. This is a good point for recommending M-78-6 for planting in highly infested area. All cultivars except M-78-1 were highly susceptible to common root rot pathogens.

For better better use of paddy lands in Mazandaran province, this study was carried out to determine the best planting date, plant density and nitrogen fertilizer levels for high yield in cauliflower cv. Snow crown. The experiment was conducted in a spilt-plot factorial design with three replications at Dashtenaz Agricultural Research Station in Sari for two years (2003-2004). The main plots were three planting dates, 5 Sep., 20 Sep. and 5 Oct., subplots three plant row distances, 50, 60 and 70 cm and three levels of nitrogen fertilizer 0, 92 and 138 kgha-1. Analysis of variance revealed significant differences among main factor, sub factors and also their interactions at 1%probability level.The highest yield (40 tha-1) was produced in treatment with planting date of 5 Sep., plant density of 60 cm (55000 plants per hectar) and application of 90 kgha-1 nitrogen. Increase in plant number per hectare by reducing plant row distances from 70 to 60 cm increased the total yield. Significant positive correlation was observed (r = 0.842) between curd diameter and fresh leaves weight. Significant positive correlations were also observed between yield and curd diameter (r = 0.580) and leaf dry weight (r = 0.545). The results of stepwise regression analysis revealed that curd diameter and leaf dry weight were the most important factors affected the yield. Accomulated nitrate did not show any significant correlation with yield and its amoumt in different treatments were acceptable.

Yellow rust is an important disease of wheat in Iran. The use of resistant cultivars is the most effective, economic and environmentally safe method to control the disease. The main objective of this study was to gain a better genetic understanding of resistance to yellow rust in ten Iranian wheat cultivars and promising lines including Chamran, Marvdasht, Shirodi, Pishtaz, Shiraz, Dez, N-75-16, N-75-15, C-78-7 and C-78-18, which were crossed with the susceptible parent Avocet"S" . Pathotype 134E134A+ with virulence on Yr2, Yr6, Yr7, Yr9 and YrA genes were used in this study. F2 populations and F3 families were studied in the green house (seedling stage) and field (adult plant stage) where they were exposed to artificial inoculation of yellow rust. F2 populations were classified into resistant and susceptible classes. F3 families were classified into three classes: homozygous resistant, segregating and homozygous susceptible. The number of genes involved was then estimated from the frequencies of families classified in each class. The results of F2 and F3 from the crosses Chamran/ Avocet "S" and N-75-16/ Avocet"S" suggested one seedling gene for each one. Crosses between Marvdasht, Shirodi, Pishtaz, Shiraz and Dez with Avocet "S" were segregated for two independent dominant genes, one as seedling resistance and the second as adult plant resistance gene. The F3 families in cross C-78-7 with Avocet"S" were segregated for two genes effective in adult plant stage. The results from the cross C-78-18/ Avocet"S" suggested two complementary dominant genes in adult plant stage, and the Cross N-75-15/Avocet"S" segregated for three dominant genes.

During 2001-2003, in an experiment, ten commercial potato cultivars Diamond, Aula, Agria, Concord, Marfona, Ajax, Desire, Santana, Picasso and Kozima were planted in a randomized complete block design with three replications. The experiment was conducted in a wireworm infested field, in Shahr-e-Kord region. Wireworm specimens in this region were collected by pheromone traps and determined. Common cultural practices, without insecticide use, were applied during the experiment. At harvest time, percentage of wireworm infested tubers were determined by counting number of tubers with more than 2mm feeding holes. Ten medium sized unattacked tubers were also randomly selected and amount of sucrose, glucose and fructose were assessed in them using HPLC. Data were analyzed and means were compared using Duncan’s test. Linear correlation were observed between infestation percentage and amount of different sugars, as well as sugar sum. Results showed significant differences among cultivars for infestation percentage, as well as for amount of glucose and fructose and sugar sum, at levels of 0.01, 0.05, 0.01 and 0.05, respectively. Ajax and Agria, having the highest and lowest infestation percentages, showed significant difference with other cultivars and arranged in separate groups. Comparison of cultivars for sugar showed that these two cultivars had the highest and lowest amount of each sugar and sugar sum. For sucrose, no significant difference was found among cultivars, while for glucose and fructose Ajax and Agria significantly differed from other cultivars and arranged, in separate groups. Correlation coefficients between infestation percentage and amount of sucrose,glucose, fructose and sugar sum were significant at levels of 0.05, 0.01, 0.01 and 0.01, respectively. It seems that sugar amount of tubers influences percentage of infestation, and effects of glucose and fructose are greater than sucrose.

In order to study the effects of different waterlogging duration in growth stages ZGS11, ZGS13 and ZGS31 on root and shoot growth of three wheat genotypes Chamran, Vee/Nac and Yavaros, a pot experiment was carried out in the Ramin Agricultural and Natural Resources University in 2004. The experiment was a factorial according to a Randomized Complete Block Design with three replications. Study of root dry weight and root elongation trend showed different responses among genotypes, start of waterlogging periods and different waterlogging levels, as short period of waterlogging (10 days), had unrecoverable effects on the growth. Analysis of variance of root dry weight and root length at the anthesis and physiological maturity stages indicated significant different among all of treatments levels. Vee/Nac genotype was found superior with respect of root dry weight and root length to other genotypes. ZGS11 and ZGS31, had the highest and the lowest responses to waterlogging, respectively. Duration of 10, 20 and 30 days waterlogging at anthesis stage decreased 37.75, 44.31 and 54.01% of root dry weight, and 25.85, 47.02 and 58.88% of root length compared to control, respectively. Investigation of the root anatomy of wheat genotypes under waterlogging stress showed formation of cortical root aerenchyma as a waterlogging-resistantce mechanism.

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most important diseases of canola in Iran and other countries. It is more distributed in north part of Iran (Golestan and Mazandaran Provinces). The reactions of four spring and two winter types of canola cultivars Sarigol, Hayola, Quantum and RGS003 (spring type)and Okapi and Talaieh (winter type) to three isolates of S.sclerotiorum, SS1Go (isolated from RGS003, Araghi Mahalleh Research Station, Golestan Province), SS2Sari (isolated from Hayola, Gharakil Research Station, Mazandaran Province) and SS3Cal (isolated from Hayola, Calale, Golestan Province), were evaluated in greenhouse conditions. Two experiment, were carried out in randomized complete block design with three replications by either wounding or non-wounding inoculation methods.Each experiment was repeated three times. Reactions were recorded as the length of the lesions five days after inoculation. Analysis of variance was applied using a factorial design for each type of inoculation separately. There were significant (P < 0.01) differences in resistance to sclerotinia stem rot among cultivars. Isolates were different in virulence and SS1Go was more virulent than the other two isolates. Winter type cultivars Okapi and Talaieh, showed more tolerance to disease, and among spring type cultivars, Sarigol was more susceptible.Wounding inoculation time was effective on lesion development and disease improvement.

In order to evaluate the effect of density on tillering capacity of wheat genotypes, this experiment was conducted with factorial design based on RCBD in three replications and two years in Maragheh Dryland Agriculture Research Station. The treatments were four seed rates 250, 350, 450 and 550 seed/m2 and six advanced wheat genotypes: V1=Azar2, V2=10 Ghazaghestan 98-99 and V3=Kiraj/87-zhong291 with high, medium and low tillering capacity, respectively and V4=885K1.1//1D13. 1/MLT/3/YE2453, V5=Gun91/Karl andV6=Fenkang15/sefid with low, medium and high thousand kernel weight (TKW), respectively. Combined analysis of results showed that genotype effect was significant for plant height, green cover percentage at flowering stage, spike length, seeds/ spike, TKW, days to maturity, productivity degree, biological yield, grain yield (p < %1) and on total tiller number, number of fertile tillers, days to flowering (p < %5). Seed rate effect was significant on green cover percentage at flowering stage, spike length, spikes/m2, seeds/ spike, days to flowering, days to maturity, biological yield and grain yield (p < %1). Genotype seed rate interaction was not significant for any of the traits. Based on these results, as no significant difference in different seed rates was observed for yield of genotypes V1, V4 and V5, therefore 250 seeds/m2 can be recommended for these genotypes. Similarly in genotypes V2, V3 and V6 seed rate of 250 seeds/m2 produced significantly lower yield compared to the other seed rates, thus 350 seeds/m2 can be recommended for these genotypes. Among yield components, only spikes/m2 and seeds/spike were affected by seed rate. The highest spikes/m2 belonged to 550 seeds/m2 and lowest seeds/spike were obtained from 250 seeds/m2. Results of correlations were similar to this inverse relationship.

Rice is the principal agricaltural crop in most Asian contries,often accounting for more than half of total cropped area. In recent years,rice production in Iran has been increased from 2.4 million ton in 2000 to 3.1 million ton in 2003. This increase in rice production is highly attributed to the wide-scale adoption of improved rice cultivars. Kadous (IR64669-152-2-3) is a new high yielding rice cultivar with good grain quality that was selected during 1994-2000 after receiving 185 germplasm accessions from IRRI. It was evaluated in observational nurseries and preliminary yield trials in1994-1995.In these experiments,Kadous yielded 5.8 tha-1, higher than the yields of improved check cultivars Khazar (5.0 tha-1) and Bejar (5.2 tha-1). It was evaluated in regional yield trials at six sites in Guilan and Mazandaran provinces in 1996 and 1997, and performed consequently, yielding an average of 5.6 tha-1, which was 0.7 and 2-2.5 tha-1 more than Khazar and local cultivars, respectivly. The Eberhart and Russell method was adopted to verify the yield stability of Kadous.The agronomic package involved a hill spacing of 25 cm x 25 cm and 90 kg Nha-1. Its maturity duration (125 days) was 1 and 2 weeks earlier than Khazar and Neamat cultivars, respectivly. It is an aromatic,semidwarf (110 cm), lodging and blast- resistant, medium-duration cultivar (125 days), with good grain quality characteristics. Its milling recovery rate is 67% with 52% head rice. In addition, the intermediate amylose content,gelatinization temperature and gel consistency of Kadous indicates a good cooking quality that preferred by Iranian consumers. Kadous was released by the Ministry of Jihad-e-Agriculture and the Agicultural Research and Education Organization in 2004.