فصلنامه تحقیقات غلات
سال سوم شماره 1 (بهار 1392)

To investigate the effect of sowing date and seeding rate on Triticale growth characteristics, a field experiment was carried out in the Rice Research Institute of Iran, during 2008-2009. The experiment was conducted as a RCBD based split-plot design with three replications. Experimental treatments included: Four sowing date (Sept. 21, Oct. 1, Oct. 10, and Oct. 20) as main plot and four plant density (275, 350, 425 and 500 plant/m2) composed of as sub plots, respectively. Measured traits, including yield, leaf and shoot dry weight and leaf area and growth Indicators as leaf area index (LAI), crop growth rate (GGR), relative growth rate (RGR) and net assimilation rate (NAR). Results indicated that interaction of sowing date × sampling time was significant effect on height, leaf dry weight and leaf area index. The Highest values of height (120.7 cm), leaf dry weight (11.21 g.m-2.day-1) were obtained in 21 Sept. in flowering time. Shoot dry weight significantly affected by triple interaction of sowing date × seeding rate × sampling time, and maximum shoot dry weight achieved in seeding rate 200 Kg.ha-1 in 21 Sept. The highest (23.5 g.m-2.day-1) and lowest crop growth rate (11.5 g.m-. day-1) were found on 21Sept. in seeding rate (200 Kg.ha-1) and 21 Oct. in seeding rate (110 Kg.ha-1), respectively.While, the relative growth rate and net assimilation rate reached their maximum with delay in sowing date and reduced seed rate (21 Oct. and 110 Kg.ha-1). In general, according to the results, The highest grain yield (5893 kg.ha-1) was obtained in the earlier sowing date and greater quantities of seed 21 Sept. and seeding rate 200 kg.ha-1) due to higher crop growth rate, leaf area index, shoot and leaf dry weight and plant height.

Effects of priming by different levels of salicylic acid (SA) on some characteristics of wheat, cv. Alvand, seedlings at two different sowing dates, conventional and late sowing dates, was investigated under field conditions in 2009-2010. The factors were seven levels of priming by SA, including control or untreated seeds, 400, 800, 1200, 1600, 2000 and 2400 μM SA and two sowing dates including conventional sowing date (23 October) and late sowing (22 November). Results showed that delayin sowing date leads to reduce emergence percent, seedling winter survival, leaf and tiller number, leaf area index, plant dry weight and leaf area ratio. Seed priming by SA improved traits such as leaf and tiller number, first leaf length, root length, fresh and dry weight of different parts of plant, soluble sugar and proline content and growth indexes Especially in conventional planting date. However, In late sowing priming only affected emergence percent, seedling survival percent, root length and proline and soluble carbohydrate content. In both planting dated, seed priming induced a reduction in S/R ratio. It seems that SA enhanced dry matter accumulation and distribution in roots than shoot. The highest number of leaf and tiller, fresh weight (total, root and crown) dry weight (total, foliage leaf sheath and crown) and S/R ratio were found in 2400 μM treatment. It seems that SA application by increment in germination rate and emergence percent and proline and soluble carbohydrate content in crown and leaf produced vigorous seedlings that had more potential to protect themselves from winter freezing compared to untreated seeds. Therefore, survived seedlings increased significantly.

Amylose content (AC), gelatinazation temperature (GT) and viscosity profile (from the rapid visco analazer curve) are primary indices for evaluating eating and cooking qualities of rice grain. The main objective of this research was to characterize the genetic parameters including main-effect quantitative trait loci (QTLs), epistatic QTLs and QTL-by-environment interactions (QEs) that are involved in the control of these traits. The experimental data were collected from a recombinant inbred lines (RILs) population derived from a cross between two Iranian varieties, Hashemi and Nemat during three years (2009-2011). A genetic linkage map consisting of 171 microsatellite markers was constructed and QTL analysis performed using QTLNETWORK 1.2 resolved the genetic components into main effect QTLs, epistatic QTLs and QEs. The analysis detected a total of 18 main-effect QTLs for the ten traits, most of them were on chromosome 6. QEs interaction were significant in seven main-effect QTLs and R2 ae ranged from 0.09 to 8.14% for each trait. Seventeen digenic interactions involving 34 loci were detected for the ten traits, and two pairs of epistatic QTLs were involved in QEs. Six QTL clusters were detected on chromosome 6 that three of them corresponding to the Wx locus and one of them corresponding to the Alk locus. Results of current research showed that some of cooking and eating quality traits are controlled by two regions on chromosome 6, Wx and Alk loci regions. The markers linked to these two genes can be used for marker assisted selection in breeding programmes.

So far to genetic improvement of rice varieties to salinity stress, considerable researches has been performed related to QTL mapping with identifying of major QTLs of Saltol and SKC1 on chromosome 1 as a result. These QTLs are involved in control of some important traits related to salinity stress. The present study was conducted to evaluate and validate of closely linked markers of the QTLs in landrace and improved varieties. With above aims phenotyping carried out as factorial experiment in randomized complete block design with two factor variety (45 genotypes) and salinity (three levels control, 6 and 12 dS.m-2 NaCl). Ahlami Tarom, Binam, Pokalli, Has. Atashgah, Dom Zard, Shahpasand Mazandaran, Tarom Mahali, Gharib, Ghasroldashti, Mousa Tarom were assigned to tolerant group under 12 dS.m-2 condition. The varieties were genotyped for 23 microsatellite markers that were introduced out of fine mapping programs as closely linked markers to major QTLs of Saltol and SKC1. The results revealed although varieties clustering in term of phenotypic traits were not very conformity with genotypic clustering, the association analysis results was conveys this fact that on the chromosome 1 in the landrace and improved Iranian varieties there are some informative and significant markers including RM10136, RM10655 and RM3412 with regression model explaining considerable percent of phenotyping salt tolerance related traits. The results of present study can be used in breeding programs such as marker assisted selection directly if the results are confirmed.

To evaluate the empirical models of competition in predicting yield loss of winter wheat, a factorial trial based on a randomized complete block design with three replications was carried out. Experimental factors were four wheat cultivars (Sayson, Alvand, Chamran and Sepahan) and feral rye densities at five levels (0, 20, 40, 60 and 80 plants m־2) at exemplary form of Dargaz, in 2010 2011 crop year. Feral rye caused a biological and grain yield reduction of studied wheat cultivars. Wheat cultivars did not have similar reaction for yield loss of biological and grain in interference with feral rye. Maximum and minimum of initial slop of biological and grain yield loss (I parameter) obtained in Chamran (6. 19 and 13. 12 percent) and Sepahan (1. 24 and 2. 62 percent) cultivars, respectively. Competition effect on biological yield of wheat cultivars was less than grain yield. Obtained relative damage coefficients (q parameter) of one and two-parameter models based on relative leaf area and relative dry matter were indicative of high competitive ability of feral rye than wheat cultivars. Models based on relative leaf area and relative dry matter of feral rye had more efficiency in predict of wheat grain yield loss in compared with yield loss-density model. Minimum regression root mean square error of observed and predicted quantities resulted of two-parameter models based on leaf area and relative dry matter of weed. Regarding to simplicity of dry matter measuring than leaf area, the twoparameter model of weed relative dry matter introduced a favorite model for predicting of wheat yield loss.

To evaluate the seeding rate effect on forage and grain yield of wheat (Triticum aestivum L.) in irrigation cultivation, an experiment was conducted as split-split plots based on randomized complete block design with three replications at Khorramabad conditions in 2011. Treatments included two cultivars of wheat (Pishtaz and Chamran), with and without green forage harvesting as sub- plots and three levels of seeds (150, 200 and 250 kg/ha) as sub-sub- plots. The plants were harvested at vegetative growth stage (tillering stage) for green forage and the physiological maturity for grain production. The measured factors were forage yield and grain yield, grain weight, biological yield, harvest index, grain number per m2, the spike number of grain per m2 and one thousand grain weights.Results showed that among cultivars, forage harvesting and seed amount were significant. The maximum grain yield, dry forage yield and thousand grain weights belonged to Pishtaz cultivar. The highest grain and biological yield, harvest Index and thousand grain weight, were obtained in nonharvesting treatment. Also, the most grain yield, dry forage yield and biological yield were depended to 250 kg/ha. Therefore, in order to produce wheat in dual purpose cultivation at khorramabad and similar climatic conditions, Pishtaz cultivar and 250 kg/ha seed rate were found to be better compared to Chamran and other seeding rates.