پژوهشنامه اصلاح گیاهان زراعی
پیاپی 8 (پاییز و زمستان 1390)

Enhancement of genetic diversity in rainfed wheat field and more attention toward specific adaptation for promoting production efficiency of microclimates in rainfed areas of Iran, are effective approaches to cope with dominant biotic and abiotic stresses and one of the effective methods to reach to these cases is to conduct a part of plant breeding program of research stations in farmers’ field (target environments) and utilizing of farmers’ indigenous knowledge and experience, through participatory plant breeding (PPB). In 2009-2010, twenty on advanced bread wheat genotypes and three checks were evaluated in PPB in Zafaran village, Islam Abad region, Kermanshah province, Iran, for grain yield, agronomic traits, physio-morphological traits related to drought tolerance such as assimilate remobilization to grain, early growth vigor, flag leaf green color intensity (SPAD reading), canopy temperature utilizing a spatial unreplicated statistical designs. Six genotypes out-yielded the best check, i.e. Rijaw. For remobilization ability Azar-2 was the superior check and two genotypes were better than Azar-2 and three genotypes were equal to this cultivar for remobilization ability. Correlation analysis reveal that average farmers’ score had positive significant correlation (P= 5%) with grain yield, indicating that farmers selection based on physical appearance of crop is reliable for selecting superior genotypes.

In present experiment callus induction and plantlet regeneration of four sesame varieties (Oltan, Yekta, Varamin and Single Branch Naz) have been considered in different environments with different hormone combinations. In order to evaluate callus induction, after surface sterilization of seeds, diploid embryos were isolated and cultured on related media enriched with 1.5, 2, 2.5 and 3 mg l-1 2,4-D supplemented with 0.1 g l-1 hydrosylate casein. In current study, comparison of percentage of callus induced showed that the highest callus percentage have been produced by Oltan (91.38%), Single-Branch Naz (90.21%) and yekta (89.30%) varieties, respectively. The poorest callus has induced in Varamin (81.47%) cultivar. Also, for shoot and plantlet regeneration, the callus samples were cultured on MS and half strength MS media supplemented with different concentrations of NAA (0.1, 0.5 and 1.0 mg.l-1), BAP (1.0 and 1.5 mg.l-1) and kin (1.0 mg.l-1). Cultivar Varamin with 25.6% regeneration has demonstrated better result than the other cultivars. the best response was related to half strength MS. Also, the best response was belongs to hormonal Composition of 0.1 mg.l-1 NAA and 1.0 mg.l-1 BAP. In root induction media that Oltan produced the highest number of roots. Half-strength MS medium has demonstrated better result than MS medium. Also, the best response was belongs to hormonal Composition with 0.5 mg.l-1 NAA and 1.0 mg.l-1 IAA.

Rhizomania disease is one of the most important diseases of sugar beet in Iran and many other parts of the world, and plays an essential role in decreasing sugar yield in fields. The best approach to control this disease is to use resistant varieties. For the involvement of resitance genes in breeding programs, tagging these genes by molecular markers is necessary. In this approach, some breeding populations and commercial varieties of sugar beet originated from Rz1 resistance source were used for validation and repeatability of some coupling molecular markers obtained from past studies. Accordingly, ELISA data related to greenhouse evaluation of rhizomania resistance were used in some breeding populations. For molecular analysis, leaf samples were taken from the plants and after DNA extraction, RAPD or PCR using related primers to markers were performed. Amplified products were separated by gel electrophoresis, stained with ethidium bromide, observed using gel documentation device and scored according to presence and absence of marker bands. Percentages of agreement between the markers results with ELISA data in single plants were estimated in breeding populations and the percent presence of the markers in commercial varieties were determined. Comparison between ELISA and molecular analysis results showed that among these markers, two coupling markers named PN1 and PN2 with ELISA agreement proportion of 57% and 71% respectively, an α error of 6% and presence of more than 80% in resistant varieties are the most suitable coupling markers to identify Rz1 resistance allel.

Polyhydroxybutyrate (PHB) is a polyhydroxy alkanote (PHA) which produces in ralstonia eutropha by three enzymes, including Beta-ketothiolase, NADPH-dependent acetoacetyl-CoA reductase and PHB synthase. These three enzymes are encoded by phbA, phbB and phbC respectively. There is considerable interest in Polyhidroxybutirate, since it can be used as biodegradable plastic, which under optimal conditions are degraded completely to CO2 and H2O. In this research phb operon was isolated from ralstonia genome using polymerase chain reaction. Specific primers were designed for PHB isolation. The PCR product was purified and cloned. Accuracy of isolation and cloning of three PHB genes were verified by nested PCR and digestion reaction. It is expected that cloning of PHB genes in expression and transformation vectors can be caused to cost effective production of Polyhydroxybutyrate as a bio-degradable plastic in plants.

To evaluate the agronomic characteristics of six mungbean varieties under normal and drought stress conditions, the experiment was conducted in a randomized complete block design with three replications at Zahak research station. Irrigation in both stress and non stress environments up to 50 percent flowering were the same. Environments with drought stress, irrigation, 50 percent of flowering to maturity and harvest the product was discontinued. Factor analysis based on principal component analysis and rotation Varimax showed that the first three factors in the environment of overall stress on the 98/89 percent and 90.52 percent of non-stress environment variables changes should be explained. Environmental stress in the first factor 45.25 percent of the variance among the traits belonged to this factor as a cause of undesirability was named. Second and third factors in stress environment 26.40 and 18.32 percent of the variation between traits and were justified as seed weight and pod size factors were named. In the first operating environment without the stress of 42.71 percent of the variance between the characters and their assigned role in the variations can be played. Under this factor was named as the cause undesirability. Second and third factors 26.12 and 21.69 percent of the variation and characteristics were explained as factors of production and yield components were named. Overall results show the effect of environmental factors on the extracted factors, the percentage variations between the characteristics and traits by factors correlated with each factor is.

In order to investigate of effect of salinity (NaCl) on soluble sugars and mineral ions concentrations in salt tolerant (IR651) and sensitive (IR29) rice (Oryza sativa L.) genotypes, a factorial based on a completely randomized design was carried out in greenhouse of physiology division of Agricultural Biotechnology Research Institute of Iran (ABRII) in 2006. Seedlings were grown in Youshida nutrient solution and NaCl stress was imposed in two levels including 0 and 100 mM at 28 days after sowing. Samples were collected from youngest leaves, leaf sheaths and roots of each plant separately at 72 and 240 hours after salinization then dry weight and concentration of Na+, K+, Ca2+, Mg2+, Mn2+ P and total soluble sugars and Na+/K+ was separately determined for each part. Results showed that under stress condition, significant reduction was occurred in dry matter of both cultivars. Na+, Cl- and total soluble sugars (TSS) concentration was increased under stress and salt tolerant was able to accumulate higher levels of Na+ and Cl- in roots to prevent toxic effect in shoot. K+ concentration was decreased with salinity and Na+/K+ ratio in shoot of IR29 was higher than IR651 while in root was lower. There was a negative correlation between Na+ with Ca2+ and Mg2+. Salt stress caused to reduction in Mn2+ concentration but P concentration showed no regular changes during stress period. This experiment showed that there was direct relation between shoot Na+ and Cl- with salt tolerance in studied genotypes. Salt tolerance in IR651 probably refers to ability of this genotype to prevent of salt accumulation in upper parts of the root and preserves lower shoot Na+/K+ ratio.

This research was carried out in order to evolution effect of salt stress on seedling growth and antioxidant activity of two safflower cultivars KW13 and IL111 in Islamic Azad University, Shoushtar branch. Salt stress treatments were applied using salt solutions with EC values of 0 (control), 4,6, 8,10 and 12 ds/m. All experiments were carried out under a dual factorial (cultivar × salinity level) completely randomized design at 3 replications. Results showed salt stress decreased root length, shoot length and seedling fresh weight but increased seedling MDA concentration, catalase (CAT) and peroxidase (POD) activity. KW13 cultivar seems to be a salt tolerant safflower cultivar since it showed the highest seedling fresh weight, highest CAT, POD activity and the lowest MDA concentration at 12ds/m level compared IL111 cultivar.