ابراهیم عزیز اف

In order to evaluation of bread wheat landraces for uptake and nitrogen use efficiency, this experiment was conducted by using 200 kg N ha-1 N fertilization and control (without using N) by spilit plot design based on RCBD with three replications in 2009-2010. The results indicated high genetic variation between native wheat landraces for nitrogen uptake and use efficiency were found. Use of nitrogen caused increasing of gain yield, number of seed per spike, spike number per m2, nitrogen content in grain and straw, grain nitrogen, nitrogen uptake and use efficiency but decreasing of harvest index and 1000 kernel weight. Analysis of variance showed that significant differences were exsit for genotypes in traits of grain yield, 1000 kernel weight, number of seed per spike, spike number per m2, harvest index, nitrogen content in grain and straw, grain nitrogen, nitrogen harvest index, nitrogen uptake and use efficiency. The interaction of Genotypes and nitrogen for all characteristic were found significantly different, except harvest index. The highest grain yields belong to G19, G26, G29, G37 and G41 compared to others. Landraces of G19, G21, G29 and G40 compared to others had highest reaction for grain N concentration and G12, G15, G28 and G31 for straw N concentration. Among relative contribution of N use efficiency components, nitrogen uptake efficiency contribution was about 85% of variation at both N levels. While Contribution of total N utilization and Harvest Index was (2-15%). The better landraces for N uptake efficiency were G9, G11, G27 and G37. In addition, landraces of G19, G26, G27, 37 and G41 were the better genotypes with their charactersitic and high yielding potential.

In order to investigate the effects of drought stress levels on seed germination and its related traits with drought stress indices, an experiment was conducted in two sparate phases with 40 wheat genotypes under field and laboratory condition for germination stages with 4 level of the polyethylene glycol (PEG) concentrations. The experimental design was factorial based on a randomized complete block design with three replications. The measured traits were radicle length, stem length, radicle length to shoot length ratio, germination rate and germination percentage. The experiment in the filed stage was conducted with 3 replications under both normal and drought stress condition. Result of the laboratory experiment indicated that effects of stress on traits were significant. Also different between genotypes were significant. The highest germination rate and percentage was measured under normal condition with 4.22 days and 79.9% respectively. Moderate level of stress (-3 bar) of drought stress had no significant effect on radical, coleoptile, stem length and dry weight, but reduced the germination rate significantly. In high level of drought stress (-6 bars) all traits were decreased significantly expect radicle length and radicle length to shoot length ratio. In control condition, positive significant correlation was observed between all traits measured in (-6 bars) under laboratory condition, with grain yield and drought tolerance indices. But in slight (-3 bars) and severe stress dry weight and radicle length had positive significant correlation with grain yield. Grain yield of genotypes showed significant differences under field study in both normal and stress condition. Results of correlation between grain yield and drought stress indices showed that stress tolerance index (STI), mean productivity (MP) and geometric mean productivity (GMP) were suitable for the genotypes identification with highest seed yield in both normal and stress conditions according to correlation coefficients between seed and its related traits and grain yield such as correlation coefficients between drought stress indices and grain yield in both normal and stress conditions, revealed that the genotypes number 39 (WS-82-9), 38 (DN-11), 22 (mbul/Alamo/M-73-18) and 25 (Alvd/Aldan/las/3--) were determined as the most tolerant and number 5 (Gasspard) and 40 (Mahdavi) were detected as the most susceptible cultivars for drought stress.

A partial set of diallel crosses conducted among seven bread wheat genotypes contain (Gasspard،M86-4،M86-6،DN-11،WS82-9 and M86-12) along with 21 hybrid، based on randomized complete block design (RCBD) with three replication were evaluated. The experiment was accomplished in a research field of agriculture and natural research center of Tehran Province in 2012-2013 in order to study genetic analysis of yield and some related traits like، grain number spike-1، plant height، grain yield،، kernel weight-1، peduncle length-1 non -fertile floret، and day to flowering. Significant (p≤0. 0l) differences were observed among genotypes for all the studied traits. The fitness of an additive-dominance model was accompanying for traits like: kernel weight، grain yield. However، for the remaining trait، when one parent was excluded، the assumptions were fulfill. Based on the estimates of average degree of dominance and result of graphical analysis gene action for the، plant height، kernel weight and number of non -fertile floret in the spike was partial dominance، while days to heading and grain yield were controlled by over dominance gen action. Broad -sense heritability estimates ranged from 51 Percent for grain yield to 75 Percent for days to heading. Narrows- sense heritability estimates ranged from 28 Percent for (grain yield to 48 Percent for grain number. Spike-1. The WS82-9 had the highest GCA effects for، grain yield،، kernel weight plant height and peduncle length and the DN-11 line and Chamran cultivar had the highest positive and significant differences for the number of grain spike-1 and kernel weight respectively. So this parents can be used for identifications and introduction of new bread wheat varieties in breeding programs. The hybridization of the 2 × 1 and 3 × 5 showed the highest values (sij) for number of grains per spike-1 and kernel weight-1 (yield two important components) respectively.