فصلنامه علوم زراعی ایران
سال هفتم شماره 1 (پیاپی 25، بهار 1384)

In this study, efficiency of AMMI method and pattern analysis were investigated. Seventeen sugar beet varieties were studied in thirteen locations over three cropping seasons and root yield and sugar content were measured. On the basis of combined analysis of variance, effect of variety and variety environment interactions for both traits were significant. The yield stabitity estimated-using Eberhart and Russell, Wricke’s Ecovalance, Shukla’s stabilty variance, AMMI and pattern analysis methods. In all stability methods used, varieties PP8, BR1 (developed is Ardabil) and IC1 were the most stable genotypes. Efficiency of Eberhart and Russell’s method for estimating of G  E interaction for both traits was lower than IPC1 in AMMI method. The efficiency of IPC1 was greater, by five to six times, than that of Eberhart and Russell’s method for root yield and sugar content, respectively. SIPC3 in AMMI method were accounted about 50 % of G  E interaction sum of squars. Biplot of IPC1 and the mean of traits for varieties and locations or environments had good efficiency for detecting of G E interaction patterns. Ranked correlation coefficients showed that AMMI method often generated more information than the other methods. Furthermore, this method generates new information which cannot be estimated by the other methods. It seems that AMMI and pattern analysis have higher efficiency for stability studies. However, results showed that using only one component of AMMI method is insufficient, and at least two components (e. g. IPC1 and SIPCf) should be considered.

In order to determine the best weed control method in spring safflower under dryland conditions and to optimize grain yield and to materialize the best use of soil and water resourses under drylands, this experiment was conducted in two cropping seasons (2000, 2001) using randomized conplet block design with 3 replications at Maragheh, Dryland Agriculture Research Station. The treatments were: A1= No weed control, A2= Two hand weedings (in mid-rosette, and before stem elongation), A3= Mechanical control with sweep cheisd before stem elongation, A4= Chemical control by Trifluralin(Ec=44.5%) with 1.5 L/ha as before planting herbicide and A5= Chemical control by Trifluralin with 2.5 Lit/ha as pre planting herbicide. Combined analysisg of variance results showed that the year effect was significant at 5% probability level on height of primary secondary branches as well as the number of capitols/plant. Control methods effect was significant at 1% probability level on weeds number per unit area, plant height and grain yield. Only grain yield was affected by year  control method interactions. Twice hand weeding with 1251 kg/ha grain yield produced the highest and was followed by chemical control with 2.5 L/ha Trifluralin with 1002 kg/ha grain yield. In conclusion chemical weed control with 2.5 L/ha Trifluralin as before planting herbicide could be recommended for Maragheh region and other regions with similar climatic conditions.

A two year experiment was conducted in 2000 and 2001 in order to investigate the effect of height of cutting and plant density on forage and grain yield of triticale (var. Juanillo 92). The experimental design was a split plot based on randemized complete block design, in which main plots consisted of 4 level of height of cutting: Cutting from 5 centimeter above ground (C1), Cutting from 10 centimeter above ground (C2), Cutting from 15 centimeter above ground (C3), No cutting (C4). All of the cutting treatments were implemented before stem elongation. Four planting densities (300, 400, 500 and 600 plant m-2) assigned to sub-plots with 4 replications. Results showed that by increasing in height of cutting significantly affected grain yield, biological yield, 1000 kernel weight, spike number per square meter and number of grain per spike. The highest grain yield (490.8 gm-2) obtained from C4 treatment (Non cutting) and the least (323 gm-2) in the C1 treatment (cutting from 5 centimeter). There were no significant differences between C3 and C4 treatments. Effect of plant density on grain yield was not significant. No cutting (C4) treatment at the 400 plants m-2 produced 500.9 gm-2 of grain. There was no significant difference between this treatment and C4D1, C4D3 and C3D3. Cutting hieght showed significant effect on forage yield. As the cutting height increased, forage yield decreased significantly. Results showed that the effect of plant density on forage yield was significant. When plant density increased, forage yield also increased, significantly. Combined analysis of variance indicated that cutting from 15 centimeter above ground at 500 plants m-2 treatment (C3D3) could be recommended for growing tritical (cv. Juanillo 92) as dual purpose crop.

In order to investigate the effect of the timing of irrigation and different nitrogen levels on grain yield and quality of sunflower crop, a field expriement was comducted using split plot design based on rardomized complete block design with 2 replications in Experimental field station, Agricultaral Research Center, Zanjan Iran in 2002 cropping season. Irrigation treatments were including: irrigation at: flowering + grain filling stages (I1), budding + flowering stages (I2), budding + flowering + grain filling stages (I3), and full irrigation with 8 days intervals (I4) assigned to main plots and nitrogen levels of 0, 90, 180 Kg/per hectare in sub plots. Head diameter, stem diameter, plant height, number of kernel per disk and 1000 kernel weight, the percentage of unfilled kernel, biological yield and grain yield as well as water use efficiency were measured for all traits measured. Results showed that there was significant difference between irrigation treatments. The highest grain yield, 4645 kg/ha, was obtained for I4 and 180kg/ha of nitrogon. Deficit irrigation and decrease in fertilizer application had significant effect on grain yield and yield components. Deficit irrigation at vegetative and grain filling stages decreased grain yield. Increasing nitrogen application had significant effect on increasing of grain yield and biological. Deficit Irrigation had their maximum effect on 1000 kernel weight among yeild compenents. Irrigation at grain filling stages decreased 1000 kernel weight up 32%. However increasing nitrogen application had no effect on this trait. Water stress at reproductive and vegetative stages caused 20% increased unfilled kernel percentage. Difficit irrigation had no significant effect on kernel number. Application of no nitrogen, However, caused significant decrease in this trait.

In order to study the adaptation and grain yield of 24 winter rapeseed cultivars, in cold regions of Iran, field experiments were carried out using randomized block design with three replications in four Agricultural Research Stations (Karaj, Zanjan, Hamedan and Shahr-e-Kord) in two successive cropping season (2000-2002). The results showed that the number of pods per plant was one of the important agronomic characteristics which implies the adaptation of winter rapeseed cultivars to cold regions. From 24 winter rapeseed cultivers studied, only six cultivars (Regent, Cobra, Orkan, Alice, Eural, Colvert and parade) were superior for crown diameter, rosette height and plant dry weight at roset stage. Orkan and Parade produced higher grain yield (3850 t/ha) and were determined as more suitable cultivars for regions with severe winter cold and late spring frost.

Two groups of sub-tropical maize germplasm including 14 early maturing hybrids and 23 intermediate-late maturing varieties with 2 adapted commercial hybrids, KSC 647 (intermediate maturity) and KSC 704 (late maturity), were evaluated in two separate experiments using randomized complete block design with 3 replications, at 4 locations in Iran (Karaj-Gorgan-Darab and Dezful), during 2002 cropping season. The results indicated that these type of germplasm performed better adaptability in Darab(28º and 46', latitude) and Dezful (32º and 24', latitude) due mainly to the similarity of the latitude to the Origin of the germplasm. The hybrids derived from crosses between varieties had competitive performance as compared to local check hybrids derived from crosses between inbred lines. Although these hybrids were early maturity at the origin, they were of late maturing behavior at the experimental sites as did local hybrids. High genetic variation, due mainly to differences between their parental varieties and different origin, as compare to temperate germplasm, these germplasm are valuable sources for temperate maize breeding programs in Iran. This is more important considering the results of the second experiment which consisted of open-pollinated varieties from only one heterotic group, and demonstrated broader genetic base. These germplasms are to be used to increase the efficiency of maize hybrid breeding programs in Iran.

In this study, effects of genotype, cold pre-treatment, low dosage Gamma irridiation and 2, 4-D concentration on response of three wheat genotypes (Atrak, F3 2005 and F3 2104) to anther culture were investigated. Seeds of donor genotypes were grown under field condition in early spring. Anthers from donor plants were collected and plated on modified CHB medium containing 2,4-D (2 and 4 mgl-1), 0.5 mgl-1 Kinetin and gl-1 Sucrose. Number of calli formed in 100 anthers and number of plantlet produced from 100 calli were counted. Results indicated that genotypes, cold pre-treatments and 2,4-D concentrations had significant effects on response of wheat genotypes to anther production, while F3 2104 the lowest. It would be concluded that androgenic traits are controlled by genotype and environmental factors. Furthermore this traits are controlled independently.