نشریه بوم شناسی گیاهان زراعی
سال ششم شماره 4 (پیاپی 21، زمستان 1389)

Walnut anthracnose is the most prevalent disease in common walnut in Iran and could be very destructive in rainy and cool seasons. The study purpose was specifying etiology and distribution of walnut anthracnose in northwest of Iran as one of the main walnut production poles. Seventy five isolates were isolated from 11 provinces located in northwest region of Iran. Perithecia were obtained from the fallen leaves or induced ongrowth media for three months at 10oC incubation. According to this study, the only species identified was Ophiognomonia leptostyla. The climates which the disease was incident were mostly cold or moderate. None of the isolates belonged to warm or semi-warm climates. It could be found in a wide range of humidity; also most of them (73%) were obtained in 1000-2000 m altitude. Pathogenicity test on walnut seedlings showed that there was huge variation based on disease index and the day of acervulus formation among isolates. Furthermore, there was a significant negative correlation between the two mentioned pathological characteristics. Isolates clustering based on their pathogenicity showed they were grouped in five categories comprising very low, low,moderate, high and very high in virulence.

In order to study the effect of different indole butyric acid (IBA) concentrations and rootstocks on propagation of rose by stenting technique, an experiment was conducted as a factorial design based on completely randomized design with three replications. First factor was rootstock (Rosa canina L., R. indica var. Major, R. multiflora L.) and second factor was 11 IBA concentrations including 0, 25, 50, 250, 500, 1000, 1500, 2000,3000, 4000, 5000 ppm. The results showed that in R. indica ‘Major’ rootstock and 25 ppm IBA had highest rooting percentage. Maximum root number was observed in R. Indica ‘major’ with 25 and 500 ppm IBA and the minimum number belonged to the control. High callus production was observed in 0, 5000 and 2000 ppm IBA. R. multiflora L. had highest shoot length compared to other rootstocks. According to results R. indica ‘Major’ and 25, 250, 1000 ppm IBA improved the success of stenting technique.

The effects of nitrogen source, amount and foliar application of urea and micro nutrients on growth traits of cucumber was studied using a factorial experiment based on completely randomizd design out in Mahneshan, Zanjan, Iran. In this study, two sources of nitrogen (urea and sulfur coated urea), three levels of nitrogen (0, 200, and 400 kg/ha) and five levels of foliar spray, including urea (2 g/l), urea + Fe-EDTA (2+2 g/l), urea + So4Zn (2+2 g/l) and urea + So4Zn + Fe-EDTA (2+2+2 g/l) were used. Nitrogen fertilizers were used befor transplanting and foliar spray was carried out when the plants were in five leaf stage and repeated in several weeks. During the growth priod, various traits such as cucumber yield, number of fruits, length and diameter of fruits, and numberof lateral branches were measured. The results showed that effects of nitrogen source and amounts, and foliar application methods of urea and micro nutrients and their interaction were significant on growth traits in cucumber. The highest yield of Cucumber (1002 g/plant) was obtained by the application of 400 kg N/ha as Sulfur Coated Urea in combination with foliar spray of Urea + So4Zn + Fe-EDTA. The results showed that foliarapplication of nitrogen and micro nutrients increased yield, fruit number, fruit length, fruit diameter and dry matter percentage of cucumber.

Drought is one of the environmental factors which damages tobacco production in many countries as well as in Iran. Therefore, breeding for tolerance to drought stress has taken a major attention in Iran. In the present investigation, combining ability, gene action and genetic analysis of four characteristics including nicotine and sugar contents and nitrogen and K2O percent were studied in five Virginia varieties of tobacco and their ten F2 populations. The materials were evaluated in two different experiments using a Randomized Completely Block Design (RCBD) with three replications at two drought stress and normal irrigation conditions in 2006 at the Rasht Tobacco Research Center. Analysis of variance revealed significant differences among genotypes for all of the traits. Diallel cross analysis was conducted using model II of method II of Griffing. General combiningability (GCA) and the specific combining ability (SCA) effects were highly significant for all the traits in both conditions. The results showed that the non-additive genetic variance had an important role in controlling nicotine and sugar content in both conditions, while, for K2O percent in non-stress condition and nitrogen percent in stress condition, the additive variance was more important than dominance variance. K394 variety innon- drought stress condition and Coker254 in stress condition were introduced as the best parents to reduce nicotine content. Coker347 in both drought stress and non-drought stress conditions was found as the best cultivar to increase sugar content. The best hybrid for decreasing nicotine content was known in both drought stress and non-drought stress conditions of Coker347
Coker254. The best hybrid for increasing sugar content in non-drought stress condition belonged to Coker347
VE1, while, no hybrids was identified with high sugar content in drought stress condition. Hayman method was also used for graphical and genetical analysis of nicotine content and K2O percent in both conditions. Graphical analysis results showed that the over dominance genetic effects were existed for nicotine in both conditions.

In order to study the genetic variation, identification and selection of superior rapeseed lines in a F4 generation, 20 advanced lines were examined using a randomized complete block design with three replications in the field of Seed and Plant Improvement Institute (SPII), Karaj in 2008-2009. Results of analysis of variance showed that there were significant differences between genotypes for the number of days to initiating and terminating of flowering, number of days to ripening, main stem length, height of first branch from ground surface, main pod length, 1000 seed weight, oil content, seed and oil yield, plant height, number of primary branches, number of pods per branch and per plant. Number of days to beginning of flowering and ripening, 1000 seed weight with 98.27, 92.52 and 91.73 grams had the highest values for broad sense heritability, respectively. The traits like number like of pods per branch and per plant with 23.13 and 16.72 had the highest values for genetic coefficient of variation (GCV). Comparison of mean seed yield showed that the genotypes L1, L9 and Zarfam
with the yield values of 3.49, 3.34 and 3.13 t/ha had the highest performance among the examined genotypes, respectively. Correlation among the measured traits showed that oil yield had a positive and significant correlation with seed yield at 1% of probability level and the traits of oil percent and the secondary pod length showed negative and significant correlation with seed yield at the %10 of probability level. Based on cluster analysis, genotypes were assigned into three distinct groups. One of the resulting clusters consisted of high yielding lines that would besuitable for selection of superior and high yielding rapeseed varieties.

Effects of plant population and nitrogen application was studied for the agronomical traits and growth indexes of castor. A split plot experiment based on a randomized complete block design with four replications was carried out at Esmaeilabad Educational Center of Ghazvin Province in 2006. Different nitrogen amounts were applied included four nitrogen levels (0, 40, 80, 120 kg/ha) and different plant density included 2.5, 4 and 5.5 plants/m2. The results revealed that the highest and the lowest yield and oil obtained where 120 kg and 0 kg nitrogen per hectare were applied, respectively. Plant densities revealed significant differences for all characteristics. The highest and least yield and oil obtained from 5.5 and 2.5 plants/m2, respectively. The intraction of nitrogen and plant density showed a significant effect on characteristics such as weight of claster, number of seeds per plant, number of seeds per square meter, weight of 1000 seeds, and seed yield. The highest weight of claster, the high number of seeds per plant and high weight of 100 seeds resulted in the interaction of the plant density of 2.5 plants/m2 and 120 kg/ha. The lowest values were belonging to the density of 5.5 plants/m2 and no nitrogen applied. High number of seeds/m2 and high yield were resulted from the interaction of density of 5.5 plants/m2 and 120 kg nitrogen/ha. Consequently, 120 kg/ha notrogen fertilizer with 5.5 plants/m2 are recommended for high yield and high oil content.

To evaluate the effect of different micronutrients application methods on concentration of elements in leaf and kernel of Zea mays L. cv. Jeta, an experiment was conducted as a randomized complete block design based factorial with three replications in Tabriz in 2008. Factors consisted of micronutrients (ZnSO4, MnSO4, H3BO3, FeSO4 and complete fertilizer) and three methods of micronutrients application (soil application, seed coating and foliar application) and no micronutrient was used in the control traetment. The results showed that the effect of different fertilizers and methods of their applications was significant on the yield at 1% of probability level.The highest yield (200.5 g per plan) was obtained by foliar application of ZnSO4 with 59 and 109.96 percent increase compared to foliar application of complete fertilizer and control treatments, respectively. Seed coating by H3BO3 prevented ear production. The results also showed that the effect of different micro fertilizers and different application methods was significant on concentration of nutrient elements in kernels and leaves at 1% of probability level. In foliar application of fertilizers mixture, H3BO3 amount reached to 63.5 and 13.91 mg in leaves and kernels, respectively, with an increase of 3.23 and 74.96 % compared to the control. Foliar application by FeSO4 increased it's concentration up to 157.7 and 5.5 percent in the leaves and kernels, respectively. Foliar application by complete fertilizer on leaves and fertilizers mixture in kernel resulted in 154.54 and 24.25 percent Mn concentration increase in corn leaves and kernels, respectively. Foliar application of ZnSO4 was also effective so that it caused of 201.95 and 149.59 percent increase in this element concentration in leaves and kernels compared to the control, respectively. It could be concluded that easy access to micro elements and their optimum application could increase their concentration in corn kernels leading to providing them in human body.

In order to evaluat the effects of banzyladenine (BA)‚ gibberellic acid (GA3) and cold, dry storage on the longevity of lilium cut flowers (cv. Fangio) an experiment was conducted as a factorial based on randomized complete block design with three replications. Cut flowers were treated with 100 mg/lit BA plus 100 mg/lit GA3 and distilled water (control) as a short-term pretreatment for 24 hours, then they kept in dry storage in 4 for 10 days. In dry storage, flowers were sprayed with 2 ppm nano silver or distilled water. After storage, cut flowers were placed in preservative solution containing 2 ppm nano silver plus 3% sucrose and were evaluated until the end of vase life. Results showed that addition of BA+GA3 (100mg/lit of each) as a pulsed treatment in solution for 24 hours prior cold storage increased petals anthocyanin, vase life (P<1%) and membrance stability index (P<5%) and decreased percentage of blasted buds and chlorophyllase activities. Stems kept in dry storage at 4 and then treated with preservative solution containing 2 ppm nano silver plus 3% sucrose produced the longest vase life (P<5%) and decreased percentage of blasted buds (P<5%).

In order to identification of chlorate resistant Fusarium oxysporum f. sp. sesami nit mutant´s phenotypes and studing their frequency, pathogens were isolated from sesame plants during 2005 and 2006 major sesame growing area in Fars province, such as Darab, Fasa, Noorabad, Kazeroon, Neiriz, Estahbab and Zarghan. In this study, 32 isolates of this pathogen with maximum genetic diversity based on geographic origin were selected for pathogenecity test. Sectors and nitrate non-utilizing (nit) mutants of isolates produced on MMC and PDC media. Frequency of nit mutants on MMC was 264 or 79.5 percent of 356 sectors and on PDC was 330 or 74.16 percent of 415 sectors. Other mutants were Crn mutants that showed minimum wild type growth on Medium containing. Phenotypic classes of chlorate resistante mutants were determined by types of growth on basal medium nitrogen sources such as sodium nitrite, sodium nitrate and hypoxanthine. Mutants were grouped in three phenotypic classes: nit1, nit3 and nitM. The frequency of nit1 in PDC was more than MMC,but frequency of nit3 and vise versa frequency of nitM on MMC was more than PDC. On PDC, 63.94 percent of mutants were nit1 but on MMC, 37.12 and 14.4 percent of mutants were nit3 and nitM, respectively.

Daffodil (Narcissus tazetta) not only is known as a cut flower and ornamental plant, but also has high advantages in perfume industry. Effect of four kinds of plant growth regulators including gibberelic acid (GA3) 100 ppm, banzyladenine (BA) 500 ppm, indole butyric acid (IBA) 200 ppm and Cycocel CCC 800 ppm) on morphological traits and essential oil of daffodil were investigated. Plant growth regulators were sprayed at two stages including bulbs and foliage parts at inflorescence. The essential oil of fresh flowers was extacted using solvent extraction method. The results showed that GA3 and BA treatments had significant effects on increasing stem length, flower diameter and number of flowers in each inflorescence and also accelerated flowering. IBA application elongated flowering stem length but CCC decreased stem length. BA and IBA applications caused significant increase in essential oil, CCC had no effect on that, but GA3 decreased its quantity.