Cereal Research
Year:2016 | Volume:6 | Issue:2|Papers Count:10

In arid and semi-arid regions of the world including Iran, soil salinity is one of the major abiotic stresses. One of the ways to achieve high performance in these areas is using salt tolerant varieties. To assess salt tolerance indices, 41 bread wheat varieties planted in randomized complete block design with three replications under normal and saline irrigation conditions (0.631 and 11.8 dS/m, respectively) in Agriculture and Natural Resources Research Center, Kerman, Iran, in 2012. The results of analysis of variance showed significant effect of salinity on grain yield, sodium content, potassium content and K+/Na+ ratio in flag leaf of the studied genotypes. Evaluating the correlation coefficients among recorded data indicated that there were the significant correlations between K+/Na+ ratio under both condition and the indices of mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM) and stress tolerance index (STI) calculated based on this ratio.Therefore, MP, GMP, HM and STI indices were the best indices for selecting tolerant genotypes.Based on these indices, the genotypes Tabasi, Arg, Akbari, Bam, Sorkhtokhm, Bolani, Sistan, Karchia and Roshan were selected as salinity tolerant genotypes. These genotypes had also high K+/Na+ ratio under both normal and saline condition. Also, the significant correlation between these indices and grain yield under stress condition showed that these indices will be useful to screen a huge set of genotypes and/or to select tolerant genotypes before determining the grain yield and is recommended as the suitable criteria for selecting the salinity tolerant and high grain yield genotypes.

Drought stress is a major contributor to deacrese growth and yield of wheat that decline the absorption of micronutrients especially zinc from the soil. To assess application methods of zinc in wheat cultivar Homa under drought stress conditions, an experiment was carried out as split plot in a randomized complete block design with three replications in Faculty of Agriculture, University of Maragheh, Maragheh, Iran, in 2013. Two factors including drought stress (complete irrigation, drought stress at emergence of flage leaf and stress at emergence of awns) as main factor and zinc application methods (no-application, priming, soil application, spraying) as sub-factor were used. The results showed that total dry matter, harvest index, yield, spike weight, spike length, plant height, peduncle weight, peduncle length, canopy temperature, proline, chlorophyll and grain zinc content significantly affected by drought stress at 1% probability level. Zinc consumption method under drought stress was also significant on total dry matter, harvest index, yield, spike weight, peduncle length, canopy temperature, chlorophyll and grain zinc content at 1% probability level. The soil application of zinc at emergence of flage leaf stage increased total dry matter up to 4733.3 kg/ha (22%), grain yield up to 1732 kg/ha (11%) and grain zinc content up to 27.7 mg/kg (77%). The results of this research showed that soil application of zinc can be recommended for rainfed fields.

To study the effects of potassium and nitrogen on antioxidant enzyme activity and changes of osmolytes in wheat under fusarium head blight infection, an experiment was carried out as a factorial in completely randomized design with three replications. The studied treatments were two levels of FHB infection (control and infected), three levels of potassium (80, 100 and 120 kg.ha-1) and three forms of nitrogen (calcium nitrate, ammonium sulfate and combination of 75% calcium nitrate and 25% ammonium sulfate). The results showed that FHB infection, potassium and nitrate increased superoxide dismutase, catalase and polyphenol oxidase activity and proline and soluble sugars contents. In contrast, infection and potassium decreased total protein and lysine content and methionine content declined under FHB infection. Ammonium sulfate led to decrease of these enzymes, proline and soluble sugars. It seems that fusarium head blight of wheat leads to increase antioxidant enzymes activity and the use of potassium and nitrate caused a greater impact on reduction of the harmful effects of this disease than ammonium, because ammonium can be reduced the osmolytes contents and the activity of antioxidant enzymes.

Water deficit stress decreased the quality and quantity of crops. To investigate the effect of salicylic acid and drought stress at reproductive stages on agronomic and physiological traits of different wheat genotypes, an experiment was carried out as split plot based on randomized complete block design with three replications in Agriculture and Natural Resources Research Center of Markazi province, Arak, Iran, in 2012-2013. The experimental factors were included irrigation with three levels (Non-drought stress as control, drought stress after anthesis along with foliar application of salicylic acid (SA) and drought stress after anthesis without salicylic acid) as main factor and seven wheat genotypes (Oroum, Zare, Mihan, Pishgam, Alvand, Roshan-back cross and C-78-14 line) as subfactor.The results showed that drought stress decrease grain yield of the genotypes compared to normal condition. The maximum grain yield under three conditions, normal (9602.7 kg/ha), drought stress (4632.7 kg/ha) and drought stress along with foliar application of SA (4935.7 kg/ha) was belong to Oroum genotype. This genotype had low ion leakage under both normal and drought stress condition. Foliar application of SA increased the grain yield of Alvand, Roshan-back cross, Zare, Mihan, Pishgam, C-78-14 line and Oroum by 75.6, 49.2, 28.6, 20.21, 19.7, 12.05 and 6.5 percentage, respectively, under drought stress. In total, the results of this research showed that the highest response of agro-physiological traits to salicylic acid was belong to Alvand and Roshan-back cross under drought stress.

To study the reaction of radiation interception, light extinction coefficient, yield and yield components of barley (Hordeum Vulgare L.), cultivar Jonoob, to planting pattern and seeding rate, an experiment was carried out in Ramin Agriculture and Natural Resources University of Khuzestan, Ahvaz, Iran, during 2013-14 cropping season. This research was conducted as strip plot in randomized complete block design with three replications. Four planting patterns (flat planting with 17 cm distance between rows, flat planting with 25 cm distance between rows, two rows on ridges with 50 cm wide and three rows on ridges with 50 cm wide) as first factor and four seeding rates (200, 300, 400 and 500 seeds per m2) as second factor were considered. Results showed that the effect of treatments on light extinction coefficient were not significant. Flat planting with 17 cm row distance, led to increase in radiation received, better distribution of light and significant increase of grain and biological yield, because maximum spike number per m2 and leaf area index. However, the maximum 1000 grain weight was obtained from three-rows on ridge. Spike number per m2 and chlorophyll index were decreased by increasing the seeding rate, but grain yield, spikelet number per spike and grain number per spike were decreased. The maximum grain yield (5072.1 kg.ha-1) was obtained from flat planting with 17 cm row distance and most appropriate seeding rate to obtain mazimum grain yield was 200 seeds per m2.

Determining the level of genetic diversity and relationships among genotypes is necessary to identify the parents for different breeding purposes. In the present study, genetic diversity of 55 samples of wild barley germplasm, Hordeum spontaneum, collected from different regions of the world was evaluated using 14 microsatellite (SSR) markers. A total of 52 alleles were amplified with an average of 5.2 alleles per locus and average frequency of the major allele was 0.51. Polymorphic information content (PIC) ranged from 0.37 to 0.81 with an average of 0.629 and gene diversity or expected heterozygosity ranged from 0.38 to 0.82 with an average of 0.635. Results of the measured diversity parameters in the studied markers showed that Bmag007, EBmac0701 and Bmac134 were the most appropriate markers to separate genotypes. Cluster analysis based on SSR dataand UPGMA method using simple matching similarity matrixassigned the genotypes into six groups. The genotypes belonging to each group were generally collected from a specific geographical region. In many cases, a mismatch between the genotypes and its geographical region was observed. Based on these results, the highest similarity was observed between Syria and Jordan genotypes and the samples from Kazakhstan had lowest similarity to the genotypes collected from these two countries. The result of this research showed that there is considerable genetic diversity in the studied wild barley samples which can be used to improve the cultivated barley after the identification of their useful genes.

A large part of lands under maize cultivation have various degrees of salinity. To study the effects of spraying time of cytokinin and auxin regulators on some characteristics of grain maize (SC704) under different planting patterns in salinity conditions, an experiment was carried out as split plotfactorial in randomized complete block design with three replications in Bushehr Agricultural and Natural Resources Research Center, in 2013. Planting pattern (ridge planting, double rows and furrow planting) was considered as the main factor and spraying time of cytokinin (control, V5-V6 and V8-V10 stages) and auxin (control, silking and two weeks later) with 50 and 10 mg.L-1, respectively, in factorial as the sub-factor. The results showed that planting pattern had the highest number of leaves, LAI, SPAD, Fm, Fv/Fm and grain yield. Double rows and furrow planting increased grain yield to 24.9% and 45.8%, respectively. Cytokinin application in V8-V10 stage increased LAI, RWC, SPAD, Fm and Fv/Fm. The lowest Fm was observed with cytokinin application in the V8-V10 stage and the highest SPAD and Fv/Fm and the lowest Fm were obtained with application of auxin in the silking stage. Application of auxin in silking stage increased grain yield (19.7%). Since the highest SPAD and Fv/Fm were produced under furrow planting with cytokinin application in V8-V10 stage and auxin in silking stage, where the highest grain yield was obtained, the spraying time together with balancing regulators under the correct planting pattern can be main factors in salinity tolerance of corn.

To investigate the effect of ascorbic acid foliar application on phenological and physiological characteristics of sweet corn under water deficits, an experiment was carried out as split plots in randomized complete block design with three replications at Hashtgerd in 2014. Three levels of drought stress (complete irrigation, moderate and severe drought stress) were considered as main plots and four levels of ascorbic acid foliar application (control, 40, 80 and 120 mg.lit-1) as sub-plots. The studied characteristics were plant height, number of grain per ear, 1000-grain weight, grain yield, total chlorophyll, relative water content (RWC), proline and superoxide dismutase (SOD) activity. The results showed that drought stress decreased plant height, number of grain per ear, 1000-grain weight, grain yield, total chlorophyll, RWC and increased proline accumulation and SOD and catalase activities so that severe drought stress conditions decreased number of grain per ear, 1000-grain weight and grain yield about 43.03, 23.11 and 49%, respectively. In contrast, ascorbic acid foliar application increased plant height, 1000-grain weight, grain yield, total chlorophyll and RWC and reduced proline accumulation and SOD and catalase activities so that the most positive effect of ascorbic acid was observed in 120 mg.lit-1. Also, ascorbic acid foliar application with 120 mg.lit-1 increased grain yield about 32.1%.

To investigate the effects of nitrogen fertilizer on yield and quality of three forage sorghum cultivars under Guilan climatic conditions, a field trial was carried out as factorial-spilt plot on time based on randomized complete block design with three replications in Rasht, Iran, during 2010-11 cropping season. The studied factors were three sorghum cultivars (Pegah, Speedfeed, KSF2) and four levels of nitrogen fertilizer (0, 50, 100 and 150 kg.ha-1). The results of analysis of variance showed the significant effect of cultivar ´ harvesting time on forage yield and qualititative traits, so that KFS2 cultivar at first harvest produced maximum forage yield. The interaction effect of nitrogen ´ harvesting time was significant on forage yield and protein, ash and ADF percentage and the highest forage yield was obtained with 150 kg.ha-1 nitrogen at first harvesting time. Also, dry forage yield, protein percentage, digestible dry matter percentage and ADF were significantly affected by the cultivar ´ nitrogen ´ harvesting time interaction effect. The mean comparisons indicated that the highest forage yield was obtained by Speedfeed cultivar with 150 kg.ha-1 nitrogen at first harvesting time. Also, maximum digestible dry matter and protein percentage as well as minimum ADF was obtained from Pegah cultivar at first harvesting time. The results of this research showed that KFS2 cultivar with 50 kg.ha-1 nitrogen or Speedfeed cultivar with 100 kg.ha-1 nitrogen are suitable to achieve higher forage yield in Rasht climatic conditions, but for better forage quality, Pegah cultivar with 150 kg.ha-1 nitrogen is recommended.

Shortage of natural resources and fear of food supply for growing population in the world caused optimal consumption of resources become great concern. To evaluate economic impact of rice-fish farming under paddy field condition, a split plot experiment based on randomized complete block design with three replications was carried out in three locations (Astaneh-Ashrafieh, Fouman and Rasht), Guilan province, Iran. Two field conditions (with and without fish) were considered as main factor and six rice varieties (three local varieties, Hashemi, Hasansaraie and Hassani and three improved cultivars, Khazar, Dorfak and Bahar1-hybrid rice) as sub-factor. Some small fishes weighting about 30-70 g (from the kinds of grass fish, Amour; common fish, Kapour and silver fish, Phytophak and Big head) were released in the pool at the same time with transplanting. About 25-30 days after transplanting, by removing the temporary border made in surrounding of fields and raising the water level of the field, it was possible to move the fishes to the rice fields. Results of the combined analysis of variance showed significant differences among varieties for all studied traits and between two culture types for all studied traits except for grain yield and number of unfilled grains.The interaction effects of culture type ´ location, culture type ´ variety and variety ´ location were also significant for grain yield. Evaluation of the grain yield of rice varieties in rice-fish farming indicated that rice and fish are complementary products for improved cultivars (except Bahar1 in Fouman) and competing products for local varieties (except Hassani in Rasht). With respect to the fish performance, the average profits of improved cultivars was 2.3 times/ ha more than local varieties.