JOURNAL OF AGRICULTURAL SCIENCE AND SUSTAINABLE PRODUCTION
Year:2003 | Volume:13 | Issue:3|Papers Count:10

Oak trees (Quercus macranthera) in Hatam Baig forest are being faced with declining and extinction. So far, about one third of the forest trees have been lost. In order to identify factors causing the decline, observations were made from 1999 to 2001. Various symptoms such as wilting, defoliation and decline were obsderved. Samples from roots, trunks, crowns and soil beneath the canopy were taken and cultured on different culture media. The fungi such as Armillaria mellea, Phytophthora cryptogea, Dematophora sp., Pythium aphanidermatum and Fusarium spp. were isolated. Considering the characteristics of the isolated fungi and according to the studies made on oak decline around the world and based on brown rot observed beneath mycelial fans in the cross sections prepared from the trunk, A. mellea appeared to be the essential causal agent of the decline. The physiological weakness and stresses in oak rootstocks caused by brown- tail moth and drought stress in the infected trees fovored the fangus activity. The biological species of this fungus was identified as Armillaria mellea (Vahl: fr) Kumm using hybridization tests and application of haploid test strains. The decline in Q. macranthera is reported as matrix nova. The report of the mentioned fungi isolated from the oak species is also universally new.

Lorestan accounts for nearly 21 percent of total lands under chickpea production in Iran. Chickpea is traditionally spring-planted under dryland conditions but there is not too much information about its appropriate seeding rate and method, particularly in the cooler parts of this western Iranian province, Azna and Ali Goodarz. Experimental design was split- factorial based on randomised complete block design with four replications. Experiment was conducted under dryland condition at Ali Goodarz during spring, 2002. Two seeding methods, 1) Planting on five 4-m long rows spaced 0.35 m apart at a 6-7 cm depth (row seeding) and 2) Planting in 4 x 1.75 m plots followed by a disk harrow (scatter seeding) were used as main-plots. Four chickpea genotypes, consisting Hashem, Jam, ILC482 and Greet, seeded on April 8-9^th, 2002 at four seeding rates, 20, 28, 37 and 45 seeds m^-2, were assigned to subplots. Among genotypes studied in this experiment, Hashem proved to be late maturing, taller in height and lower in terms of all grain yield components, grain yield and harvest index and Greet appeared to be early maturing and higher in pod number per plant, and 100-grain weight and therefore in dry matter and grain yield and harvest index, as compared to the rest of genotypes. With an increase in seeding rate, most grain yield components showed a non-significant decrease, leading to no significant changes in average grain yield but a significant decrease in harvest index of the genotypes, due mainly to a non-significant increase in dry matter yield. Seedling emergence of all genotypes with broadcasting seeding varied from 50 to 60 percent of that with row seeding, leading to the non-significant plant yield components in the former seeding method. Due to a greater number of seedlings established under row seeding, both dry matter and grain yield with this seeding method were considerably greater than with seed broadcasting. Despite a generally low grain yield obtained with the present genotypes under dryland conditions of Ali Goodarz, it could be concluded that with seeding at an appropriate early date and with row seeding of 20 to 28 plants m__2 a more considerable grain yield might be produced from spring chickpea under dryland conditions of Ali Goodarz.

The response of two advanced winter wheat cultivars (SXL/Glenson, SXL/Vee S) at different fertilizer and seed rates was studied and compared with Sardari in dryland conditions during 1994-96 at the Haydarlo station, in Oroumieh. Experiment was set up in split-split-plot design arranged in randomized blocks with three replications. Three wheat cultivars (V l=SXUG1enson, V2=SXL/Vee S and V3=Sardari) were located in main plots and three seed rates (S1=300, S2=350 and S3=400 seeds/m2) in sub-plots and three fertilizer rates (N15P15, N30P30 and N45P45) in sub sub-plots. The results showed that interactions of variety x seed rate x fertilizer x year rate were highly significant. Maximum yield was achieved from Sardari with 350 seeds at N30P30 in second year (3.23 t. ha 1) and minimum yield resulted from Sardari with 300 seeds at N15P15 in third year (0.81 t. ha-). In addition, from the results of fertilizer effects, the N45P45 and N30P30 treatments had yields at same category, but their yields differed with N15P15 treatment. Variety and seed rates did not show any significant differences on crop yield. The conclusions for optimal winter wheat production in the study area and similar regions are; (i) a seed rate of 350 seed per m2, (ii) fertilizer amount of N30P30, (iii) each one of cultivars.

The leaf number per seedling length of longest stem cotyledon length and width, unifoliate internode length and leaf blade length and width were measured on over 2000 individual 30-days old seedlings. The seedlings were transplanted to the field and individual plants fresh and dry weight number of shoots per plant and plant height were measured on 900 plants in each of four harvests. Days until 50% flowering percentage of ground cover fresh and dry weight of leaves/plant ratio and size of trifoliate leaves were also measured in experimental plots. The path analysis for yield indicated that most effective traits on fresh and dry yield are plant height and number of shoots respectively. Based on multivariate analysis of variance of 30 half-sib families for all traits measured on seedling and mature plants significant differences were obtained showing genetic variation between families under study. Additive variance for most traits was significant. Heritability based on family mean was more than individual plant base. General combining ability for yield and relative traits were estimated. This information will be used for constructing synthetic varieties from families having good general combining ability.

The genetic basis of relative salinity tolerance was studied at germination stage of rapeseed (Brassica napus L.) cultivars at 0 100 and 200 mM NaCl salinity using a 6 parent F__1 diallel. The parents were chosen to reflect the range of tolerance in a larger sample of over 20 varieties previously assessed for variability in salinity tolerance. Analysis of variance for each salinity level showed high significant genotypic differences for coefficient of velocity of germination (CVG) germination index (GI) and mean germination time (MGT) at control and for CVG GI MGT and germination rate index (GRI) at 100 mM NaCl salinity level. At 200 mM NaCl no significant differences obtained among genotypes. At 100 mM NaCl both additive and non-additive effects were significant with the prevalence of dominance gene action over additive effects. Recessive genes controlled tolerance in all traits examined. The estimated broad sense heritabilities were high while narrow sense heritability estimates were low indicating relatively high dominance gene effects. Analysis of combining abilities showed that both additive and dominance effects were important in genetic control of germination parameters at 0 and 100 mM NaCl. Since recessive genes governed tolerance the tolerant parent was one of the poorest specific combiners. Large heterotic combinations in some crosses and the existence of significant dominance effects suggested the potential of hybrid rapeseed breeding for soils with salinity problem.

The fertile plain of Shabestar is located 40km. west of Tabriz and northeast of Urumiyeh lake and its area is about 617 km^2. Shabestar plain is an active cultivated area with low annual precipitation and surface runoff thus. the groundwater resources have a vital role in supplying agricultural drinking domestic and industrial water demands. Saline water intrusion into the fresh water aquifers is highly increased in recent years and some of abstraction wells are left unused. The purpose of this paper was to determine origin of the water salinity in the plain. Therefore from the previous hydro-geological data and several number of sampling from the plain wells two groups of saline water were distinguished. Group 1 contain the low ratios of S04/Cl and Na/Cl and high percent of Ca + Mg. Saline water of the central parts of the plain lies in this group. Group2 contain the high ratios of SO__4/Cl and Na/Cl and low percent of Ca+Mg. Saline water of the southeast and south margin of the plain lies in this group. In the central parts ratios of SO__4 and Cl to the sum of anions are similar to those of the Urumiyeh Lake. Consequently saline water source in these parts can be related to Urumiyeh Lake. However in the southeast and south margin of the plain ratios of SO4 and Cl to the sum of anions are different from those of the Urumiyeh Lake. Evaporation from the shallow groundwater seepage from saline rivers and dissolution of the evaporational deposits are causes of the salinity.

Antibiosis potential of four rapeseed oil varieties namely: Eurol Okapi PF and Boomrang to cabbage aphid were studied at 20±2°C 60±10% (RH) and photoperiod of 16:8 (L: D) in two separated experiments. In the first experiment parameters measured for making inferences about antibiosis were pre-reproductive period reproductive rate and intrinsic rate of increase (r__m). The experiment was arranged in a completely randomized design with ten replications. Seeds were planted in pots with 12cm diameter by 15cm height. Plants were infested at the 2-3-leaf stage. Experiments were initiated with nymphs less than 24 hours old. When they were developed to adult cages were inspected daily for nymphs. Nymphs were counted and removed until the adult aphids died. In the second experiment in order to measure the mean relative growth rate (MRGR) 10 one day nymphs were weighed and confined in leaf cages (one nymph per cage) on the plant varieties. Thereafter they were let to feed for four days and weighed again. Results indicated that Boomrang was the most susceptible variety. Parameters such as reproductive rate (3.87 nymph / day) and r__m (0.29) were significantly higher in Boomrang than other varieties. Okapi was relatively the most resistant variety in this experiment.

Fatty acids profiles of 15 representative strains of common yellow pigmented bacteria associated with citrus bacterial canker disease were determined by gas liquid chromatography. Results of data analysis via MIS version 3.2 software classified the strains into three groups. Strains from the first second and third groups had 10 18 and 9 types of fatty acids respectively. Main fatty acids were 15:0 anteiso 16:0 iso 16:0 and 17:0 anteiso for the strains of the first group and they were identified as Curtobacterium flaccumfaciens. Major fatty acids charactristic of strains of the second group were 14:0 15:0 16:0 17:1 w8c and 18:1 w9c and they were identified as Rhodococcus faciens. Main fatty acids of the third group of the tested strains included 14:0 16:0 16:1 cis 9 and cyclo 17:0 and they were identifeid as Erwinia herbicola.

To evaluate drought resistance indices in spring barley genotypes a factorial experiment based on randomized complete block design was carried out with three replications in Khalatpooshan Agricultural Experiment Station University of Tabriz Iran during 2001 growing season. Treatments were five genotypes (MB76-17 IB78-26403 Valfagr Sefidan and Gharamalek) and four irrigation regimes which were applied at the following growing stages: 1- seedling emergence and booting 2- seedling emergence booting heading. 3- seedling emergence booting and seed milk stage 4- seedling emergence booting heading and seed milk stage. The last irrigation regime (No.4) was considered as control treatment. Several drought resistance indices including mean productivity (MP) geometric mean productivity (GNP) tolerance index (TOL) harmonic mean (HAR) stress susceptibility index (SSI) and stress tolerance index (STI) were estimated based on grain yield of the genotypes both under stress (Irrigation regimes of 1 2 and 3) and non-stress conditions. Correlation coefficients of these indices with each other for indices such as MP GMP HAR and STI were highly significant in both stress and non-stress conditions. Because STI was correlated with MP GMP and HAR indices and also differentiated the genotypes belonging to A group from other groups effectively therefore it could be recommended as the most suitable index for selecting drought resistant barley genotypes. Three dimensional diagrams of Y__p, Y__s and STI which were made for each irrigation regime also revealed that line IB78-26403 and landrace of Gharamalek were the most drought resistant amongst the genotypes under study in both severe (1^st irrigation regime) and moderate (2^nd irrigation regime) drought stresses.