فصلنامه تحقیقات غلات
سال سوم شماره 4 (زمستان 1392)

To investigate drought tolerance indices and identify drought tolerant genotypes in durum wheat, 20 advanced durum wheat genotypes along with three checks, Zardak and Saji (durum wheat checks) and Sardari (bread wheat check) were assessed in a randomized complete block design with 3 replications under two rainfed and supplemental irrigation conditions in the Drayland Agricultural Research Sub-Institute (Sararood, Kermanshah, Iran) in 2010-11 cropping season. Drought tolerance indices i.e. mean productivity (MP), tolerance index (TOL), genomic mean productivity (GMP), harmonic mean (HAM), stress susceptibility index (SSI), stress tolerance index (STI), yield index (YI) and yield stability index (YSI) were calculated on the basis of grain yield in the both stress and nonstress conditions. The genotypes No. 2, 4, 8, 21 (Saji) and 18 with the highest values of MP, GMP, HAM and STI were found to be tolerant genotypes, while the genotypes 12, 21 (Zardak), 16 and 19 with the lowest values of TOL and SSI had the least susceptibility to drought stress. Biplot analysis indicated that the genotypes No. 8, 21 (Saji) and 18 were characterized by the indices of MP, GMP, HAM and STI as drought tolerant genotypes. The results of this research showed that in all of the genotypes, genotypes No. 8, 21 and 18 were tolerant genotypes.

Agricultural production in arid and semi-arid regions always is affected by soil salinity and weeds competition. In order to study the effect of soil salinity on competition between wheat and rye, a factorial replacement series experiment based on completely randomized design with 3 replications was conducted in research greenhouse of faculty of Agriculture, at University of Birjand, in 2012. Four different ratios of wheat-rye (100-0, 75-25, 50-50, 25-75, 0-100 percentage) and 4 levels of soil salinity (2, 4, 8 and 16 dS.m-1) were used as experimental factors. The results indicated significant (P<0.01) effect of salinity on dry matters of wheat and rye. Increasing soil salinity from 2 to 16 dS.m-1 decreased 84% and 90% of the dry matter of rye and wheat, respectively. Competitive ability were more at salinity levels of 2 and 4 dS.m-1 in rye and 8 and 16 dS.m-1 in wheat. Investigation of competition by several indices indicated that increasing of salinity level can decrease competitive ability of rye versus wheat.

To evaluate the effect of organic fertilizer complements application (Aminol Forte, Fosnutren and Kadostim) on grain yield, milling properties and nitrogen use efficiency of two rice (Oryza sativa L.) cultivars, a field experiment in factorial layout and randomized complete block design with 10 treatments and 3 replications was conducted at Rice Research Institute of Iran in 2009. Treatments included: fertilizer in 5 levels [complete chemical fertilizer (for cv. Khazar: nitrogen 90, phosphorus 45 and potassium 75 kg.ha-1 and for cv. Hashemi: nitrogen 60, phosphorus 30 and potassium 50 kg.ha- 1, respectively, complete chemical fertilizer + organic fertilizer complements (Aminol Forte, Fosnutren and Kadostim one l.ha-1 as a foliar application in tillering, booting and milk stages), 50% of chemical fertilizer + organic fertilizer complements, organic fertilizer complements and control (no fertilizer application)] and two rice cultivars (cv. Khazar and Hashemi). Traits that been measured were; grain yield and yield components, morphological characteristics, milling properties and nitrogen use efficiency. Results indicated that experimental treatments had a significant effect on the tillers fertility, number of filled grain. panicle-1, grain yield and 1000 grain weight. In this traits, complete chemical fertilizer and complete chemical fertilizer + organic fertilizer complements treatments had had similar effects and lowest amount obtained from organic fertilizer complements and control (no fertilizer application) treatments. The highest grain yield (5371 kg.ha-1) obtained in complete chemical fertilizer + organic fertilizer complements treatment. Organic fertilizer complement treatment and 50% of chemical fertilizer + organic fertilizer complement treatment showed the highest nitrogen uptake efficiency (26.4 kg.kg-1) and nitrogen harvest index (48.3 %), respectively. Results indicated that organic fertilizer complements application, eliminated chemical fertilizers rate that enhanced nitrogen uptake efficiency parameters.

To investigate the effect of various levels of Oxadiargyl and Thiobencarb herbicides on yield and yield components of rice (Oryza sativa cv. Hashemi), an experiment was carried out as a randomized complete block design with 8 treatments in 4 replications, in Rice Research Farm of Agriculture Faculty of Guilan University in 2011 growing season. In this experiment, the effects of Oxadiargyl (450, 900 and 1350 g.a.i ha-1) and Thiobencarb (1500, 3000 and 4500 g.a.i ha-1) herbicides were investigated. The two untreated control and hand weeding twice was also considered. Rice plant height, number of filled and unfilled grains per spike, grain yield and biological yield were significantly affected by treatments. But, there was no significant effecton 1000- grain weight and harvest index. The more than recommended concentration of Thiobencarb and Oxadiargyl increased 61/7 and 54/3 % the grain yield in comparison with untreated control that was not significantly different from each other. The Most plant height (134.6 cm), number of tillers (16.6), number of grains per spike (76.4) obtained at high concentration of Thiobencarb that 10 to 44 percent higher than untreated control. The lowest number of tillers, grains per spike and plant height obtained at untreated control and the lower than recommended concentration of two herbicides. In general, the high levelsof Thiobencarb and Oxadiargyl herbicides with control 75 and 69% of the total dry weight of weeds and 69 and 71% of the total density of weeds in comparing with untreated control showed higher efficiency in weeds control and performance better in comparing with low levels of self.

Iron is one of the essential micronutrient, which has an important role in nitrogen fixation and activity of some enzymes such as catalase, peroxidase and cytochrome oxidase. To map QTLs for the traits associated with iron accumulation in barley, 148 doubled haploid lines derived from a cross between Clipper an Australian two rowed cultivar and Sahara3771 Algerian six rowed landrace were evaluated under greenhouse condition and single plant grain yield, 1000 kernel weight, single plant iron concentration and content at grain were measured. To saturate linkage map of the population, 26 retrotransposone markers, IRAP and REMAP markers, 246 SSR and EST-SSR, 238 RFLP and one morphological marker were used and covered 1099.09 cM of barley genome with an average distance of 2.37 cM between two adjacent markers. Transgressive segregation was observed for all traits indicating the presence of desirable parental allele combinations in the progenies. In total, 511 polymorphic markers were mapped in 7 linkage groups. For single plant grain yield, six QTLs were mapped with positive additive effects except one. Three QTLs were identified for seed weight which QTL on 2H with positive additive effect explained 70% of the phenotypic variation. For single plant iron concentration and content at grain six and four QTLs were detected, respectively that five and two QTLs had negative additive effects. QTLs had negative additive effects indicating the role of Sahara3771 alleles in increasing iron accumulation in offspring. Two common genomics regions for the QTLs of some traits were identified which could be due to linkage between the QTLs or their pleiotropic effect. Given the strong linkage markers associated with QTL positioning, these markers can be used in marker-assisted breeding programs.

Barley (Hordeum vulgare) known as a tolerant plant to salinity and has capability to produce reasonable yield under saline conditions. Salinity decreases water uptake by seeds and can lead to delay in germination and seedling establishment. To investigate the effect of salinity on barley germination, three different experiments were carried out in completely randomized design through 13 treatments each with three replications. In these experiments, germination process was studied within three different media including NaCl+CaCl2 solution, natural saline water and natural saline soil. Studied variety was the spring variety, Tropy. The salinity levels in all experiments were consisted of control (0.005), 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25 and 27 dS.m-1. The germinatedseeds were counted at designated time intervals and continued up to full germination or until the consecutive counting were the same. The number of germinated seeds as well as the germination rates were then calculated and analyzed. The results indicated that by increasing salinity, both percentage and rate of germination decreased. There were further reductions in natural saline water than the NaCl+CaCl2 solution. In higher salinity levels, the germination rate was decreased, while the required time for germination has increased. Seeds were germinated in all salinity treatments within the NaCl+CaCl2 solution. But in the soil medium, germination was successful up to 13 dS.m-1 and the germinated seed numbers were rapidly reduced such that in 23 dS.m-1 treatment no seed was germinated. This observation can be attributed to the fact that in the saline soil medium, the matric potential is also reducing the seed water uptake.