نشریه نهال و بذر
سال شانزدهم شماره 4 (زمستان 1379)

In order to investigate pathogenic variation in population of the causal agent of yellow rust, and evaluate resistance of wheat cultivars and advanced lines released before and after 1992, the year of epidemic of yellow rust in Iran, known genotypes for resistance to yellow rust, including yellow rust differential cultivars, yellow rust near isogenic lines, some sources for adult-plant resistance genes, and genotypes carrying factors for durable resistance, were evaluated in Northern, Northeast and West provinces of Iran. According to the results obtained, virulence factors for Yr1 were present in Neishabour, Torogh, and Jolgehh Rokh in Khorasan province (Northeast) for Yr2 in Neishabour, Torogh, and Jolgeh Rokh (Northeast), Kalaleh and Gharakhill (North) Ultan, Jafarabad, and Alagrogh (Northwest) for Yr3 in Neishabour for/Yr6, Yr7, and Yr9 in all regions for Yr8 in Jolgeh Rokh, Kalaleh, Ultan, Jafarabad, and Alarogh for Yrll in Torogh and Gorgan for Yr12 in Torogh, Gorgan, and Ultan for Yr18 in all regions except Agh Ghala and Torogh for Yr22, Yr23, Yr25, and YrA in all regions for YrSu in Lalaleh, lafarabad, and Alarogh for undesignated resistance genes present in Nugains cultivar (YrA1 and YrA2) in Neishabour, Torogh, Jolgeh Rokh, Gorgan, Jafarabad, and Alarogh for Yr27 (YrSK) in Torogh. For genes Yr4, Yr5, Yr10, Yr14, Yr15, Yr24, YrSD, YrCV, and YrSP virulence factors were not observed so far, thus these genes are recommended as effective genes, which can be used as resistance sources for use in breeding programs. All Iranian old wheat varieties, which had been released before 1992, were highly susceptible in all nurseries and among newly released varieties, Tajan was susceptible in Torogh Mahdavi in Neishabour Alamout and Zarrin in Torogh Alvand in Neishabour Chamran in Neishabour and Jolgeh Rokh. Wheat advanced lines C-73-5 and 8-75-20 were susceptible in Alarogh, M-75-10 in Jolgeh Rokh, M-75-19 in Kalaleh, and N-75-5 in Torogh.

Due to the importance of flower initiation and further development of flower buds in fruit set and yield, this research was conducted to explore flower formation and differentiation of mature Ovhady cultivar as one of commercial pistachio cultivars. Flower buds of this cultivar were collected during 10 months period and fixed using FAA. After preparation of the microscopic slice and staining, microscopic observation based on Tunica-Corpus hypothesis revealed that when vegetative bud moves towards differentiation, the number of cells decreased in Tunica Zone. Observation of morphologic changes were detected the initiation of rachis formation was at the end of April and completed in June. Differentiation of pistil started in September and visualized in October. Flower buds had not any growth in winter. Floral primordia (Pistillate) produced quickly three carpels and will be ready for anthesis at the end of March. In conclusion, the results from the present study of pistachio flower physiology will be used to facilitate pistachio orchard management.

Small fruit size is one of the major problems in mandarin production. This experiment was conducted in order to increase fruit size and quality of Satsuma mandarin (Citrus unshiu) using synthetic growth regulators. Mature Satsuma mandarin trees with sour orange (Citrus aurantium) rootstock were treated with 2,4-Dichloro-phenoxy acetic acid (2, 4-D) and naphtaene acetic acid (NAA) at the concentrations of 0, 10, 30 and 60 mgl-1 and 0, 300, 400 and 500 mgl-1 respectively. Results indicated that auxins had effect on the size and diameter of fruits. NAA at the concentration of 400 mgl-1 and 2,4-Dat 30 mgl significantly increased fruit weight when compared with untreated control. In addition, pH of the fruit juice was also affected and showed an increase, however TSS was reduced. Both growth regulators increased juice content, but not the percentage. In conclusion, the marketability of fruits were improved by both growth regulators, and the best result and appearance was obsereved using 400 mgl-1 NAA.

In order to study the the effects of planting dates on durum wheat cultivars and lines, this experiment was conducted in 1997/98 and 1998/99 cropping in Maragheh region. The experimental design was strip plot based on RCBD, with three replication. Horizontal factor was allocated to two planting dates (early planting in early October, and late planting in late November), and vertical factor was 11 durum wheat cultivars and lines. In different plant growth stages some agronomic traits and grain yield were recorded. The results showed that, effect of planting dates on number of days to heading and maturity was significant (?=1 %) however, effects on other traits were not significant, but the first planting date had more grain yield than the second date. The effect of cultivar on number of matured tillers, number of seeds per spike, spike length, spike weight, plant height, days to heading and maturity and grain yield was significant (? = 1%), but its effect on grain filling duration was not significant.

In order to evaluate exponential model parameters of dry matter and nitrogen accumulation in grain of spring wheat genotypes, this study was conducted in Ahvaz Research Station in 1998-99 cropping season. Dry matter and nitrogen accumulation trends were studied in two seprated experiments. In the first experiment, irrigation was carried out normally until physiological maturity, while in the second experiment, the last irrigation was done one week before anthesis to make post - anthesis drought stress. Results showed that exponential model Y = A/ 1 + exp [ ? - DAA)/?] properly explained dry matter and nitrogen accumulation sigmoied trends. Cosidering the high significant correlation of A prameter with dry matter or nitrogen accumulated in physiological maturity, the model was determined as mathematical formula Y = Ym/ 1 + exp [(?- DAA) / ?] . Using canonic correlation results and multivariate statistical analysis and refer to high correlation of ? parameter with effective filling period (EFP) and calculation method of : EFP = Ym / b in which b is the regression slope in gpain linear growth period, parameter ? and also ? will be easily eveluated by determining Ym and b. High significant correlation of actual and estimated data from the above mentioned model and also high determination coefficient oflinear regression based on estimated data(Yest.) and actual dala (Yact.), showed minimum error for model parameter calculation and unbaised evaluation from this introducied method for determination of grain dry matter and nitrogen accumulation in studied genotypes and every sigmoied trends.

To study different assessment methods of resistance to spread of Fusarium head blight, the resistance of 28 genotypes of spring wheat (Triticium aestivum L.) was evaluated with 2 isolates of F. graminearum in the greenhouse by point injection method. Data for final disease rating, collected 28 days after inoculation, calculation of area under disease progress curve (AUDPC) based on disease scores on 7, 14, 21 and 28 days after inoculation and percentage of infected rachises, were statistically analyzed. For the three assessment methods variation among genotypes was significant. Significant correlation among 3 assessment methods indicates that these methods measured the same basic process of disease spreading within the head. The similarity of resistant evaluation results based on diseased spikelets. Final disease rating and AUDPC and rachis infection, indicated that rachis is the most important barrier for Fusarium spread in wheat spikes.

A Randomized Complete Block Design experiment was conducted to determine the suitable rotation for wheat in Kermanbshah provine. Six crop rotation chickpea-wheat, lentil-wheat, wheat-wheat, fallow-wheat, vetch-wheat, medic-wheat with 4 replications were studied in 2 sites of Sararood Rainfed Research Station. The results of 3 complete rotation periods showed a significant difference in wheat grain yield. Among different crop rotations, medic-wheat rotation was classified in group I and wheat-wheat and vetch-wheat in group II. The remaining treatments varied between these two groups. Chickpea-wheat and lentil-wheat crop rotations were the most suitable from the economic and yield production points of view and are recommended for Kermanshah province.

Eggplant (Solanum melongena) has become adapted in Bushehr province and the area under its cultivation is about 1500 hectars annually. In order to obtain suitable cultivars for the region, an experiment was carried out in a Randomized complete block design with 10 cultivars in 4 replications for tow years (1995-1996) in Agricultural Research Center of Bushehr Borazjan. After nursery, 8-10cm height seedlings were transplanted for bed planting in 4 rows on rigids with 80cm width. Plants were sown 50cm apart from each other. Manuring and fertilizers applied were 15 tha-1, urea 180 kgha-1 and ammonium phosphate 120 kgha-1, respectively. The plots were irrigated 54 times during the growth period, weeding took place 3 times and pests control were done 2 times. Yields and agronomic traits of cultivars were measured in apprepriate times. The results showed that cultivars AUB 127 and Black Beauty (Royal) with 57.4 and 44 percent more yields than check cultivar, respectively, were selected as the most suitable cultivars and therefore they are recommended for cultivation in this provinc.

The cultivar was selected first based on individual plant selection from Moghan's landrace population at Agricultural Research Center of Moghan in 1982. Single plant selection from the population, evaluation of the single plants and yield trial of the selected lines were carried out for four years. Seventy seven lines were selected and tested in two cosecutive preliminary yield trials which following that the number of the lines were reduced to 25 and 12, respectively. Regional and National yield trials were conducted at Moghan and Karaj, Sari and Moghan, respectively for three years each. Line no. 11 with average yield of 1377 kgha-1 produced the highest yield. Stability analysis on yield indicated the stability of the line. This line showed better performance than the local check in verificational trial in Moghan region in 1992. Field studies showed that this line is tolerant to damping-off disease. Written report of the line was approved in Agricultural Research, Education and Extension Organization meeting No. 458 in 1999, and Oltan name was accepted for it.