Cereal Research
Year:2015 | Volume:5 | Issue:2|Papers Count:7

To study the haplotype and allelic diversity and to identify the informative markers of root characteristics of some rice genotypes under drought stress, 17 microsatellite markers linked to the major QTL located on the rice chromosome 9 controlling root morphologic characteristics under drought stress were used. Based on the genetic data, the studied rice genotypes were assigned into two groups. The genotypes of first group including Bala were more tolerant and the genotypes of other group had lower root characteristics and were more drought sensitive. Results of the molecular analysis showed that RM215 and RM24671 markers at this chromosomal region had the most allelic variation. The association analysis between markers and traits under stress condition were revealed that the SSR markers RM530-A with root thickness (B=0.431), RM24627-A with root weight (B=0.573), RM24669-C with root number (B=0.620), RM6535-C with stem weight (B=-0.503), RM684-A with stem length (B=0.832), RM160-A with root length (B=0.373), RM684-A with genetic code (B=-0.811) and RM24627-A with biomass (B=1.073) had the highest standardized regression coefficient and can be used in the breeding programs as informative markers, if the results are confirmed by further experiments. Results of the haplotype analysis divided twenty two genotypes into 16 different haplotypes and the haplotype 8 consisting of Deilamani and IR25571 had the maximum similarity to Bala. It seems that this similar genotypes to Bala be included the QTLs controlling drought tolerance at this genome region. These genotypes can be used for drought tolerance breeding programs after validation of the results in subsequent experiments.

The objective of this study was to investigate the socio-economic effects of accepting the second culture after rice in Fouman township, Guilan province, in 2014. Therefore, twenty two social indices in seven major factors including participation, safety, education, youth and women attend, current status satisfaction, unemployment and immigration and three economic indices in qualitative and quantitative scales based on the Likert’s six-point scale were assessed. This research was carried out by casual-descriptive method with random sampling assortment from the studied villages and data were collected from 202 paddy farmers (101 accepters and 101 non-accepters of second culture) using the questionnaire. The face validity of the questionnaire was assessed and revised by the University Staffs and Agricultural experts. To evaluate the reliability of the questionnaire the test-retest method was used. Data was analyzed using the t-test, effect size and cost-benefit analysis. Results indicated that income and profits rate derived from the main (rice) and second culture in one cropping year was higher in the acceptors than the second culture non-accepters and its economic terms advantageous. The most important social impact was reducing in immigration and unemployment in the families of second culture acceptors. Furthermore, the social indices such as participation, current status satisfaction, safety, education and youth and women attend improved respectively with the implementation of the second culture.

Wheat is one of the most strategic agricultural crops across the word and its production plays a significant role in human nutrition. Water resources scarcity and sequential droughts events in Iran are two challenging issues in providing water for strategic crops such as wheat. In the other hands, large amount of wheat is annually imported to the country which needs more attention to wheat virtual water and its economy. The objectives of this study were to determine the amount of green and blue virtual water of wheat, irrigation water price and virtual water flow in Iran and in particular in Fars province for ten consecutive years. Consequently, the cultivated areas, crop production and precipitation data were collected for the period of 2000 to 2010. The potential evapotranspiration of wheat for every province was obtained using NETWAT package. Calculating the actual evapotranspiration with FAO crop water production function, the effective rainfall as well as the blue and green virtual water and irrigation water price were determined. Results indicated that changing the land use from dry to irrigated farming and mismanagement of water and soil resources as well as disregarding the climate have increased the irrigated area, virtual blue water and costs being followed by decreasing dry farming cultivation area, virtual green water and crop yield in Fars province. Although the irrigated areas were increased in last two years in the country scale, the irrigated yield was reduced which increased virtual blue water and costs. There exists no scientific, economic, environmental and practical justification for such consequences and the costs which imposed on the government and people are not returnable.

Salinity is a major abiotic stress in crop production and occurs in many regions of Iran. Since yield are reduced by the toxicity of salts, therefore, production and introduction of high yielding and tolerant varieties can be useful and effective on losing the impact of this phenomena in accordance with other ways to combat soil and water salinity. This experiment was conducted to identify the Iranian bread wheat varieties (Triticum aestivum L.) suitability for planting in saline areas. Forty one varieties were assessed in a randomized complete block design with three replications. To evaluate varieties for salt tolerance, eight indices of stress tolerance and sensitivity were used. The varieties for grain yield showed significant difference from each other. The correlation coefficients indicated that STI (stress tolerance index), MP (mean productivity), GMP (genomic mean productivity) and HM (Harmonic mean) were the best criteria for selection of high yielding varieties under stress and non-stress conditions. Principal components analysis showed that two PCs explained 97.15% total variance. Cluster analysis based on tolerance and sensitivity indices built four distinct groups. In addition, according to results of the three dimensions scheme, biplot analysis and cluster analysis, Shiraz and Arg varieties were determined as the most tolerant varieties to salinity stress which can be used in the future breeding programs.

The cold resistance in wheat varieties that been controlled with compatibility procedure to environment such as vernalization requirement and photoperiod reaction, has been factors for success in cold regions. Thus, knowledge of the eco-geographical distribution of influencing vernalization requirement and photoperiod reaction genes is essential for modern breeding program. To do so, 119 lines and cultivars of Iranian wheat were studied. Specific primers based on the polymerase chain reaction (STS-PCR) to identify alleles affecting the sensitivity to vernalization were used in Vrn-A1, Vrn-B1 and Vrn-D1 loci. For agro-ecological study of the diversity and distribution of these genes in Iran, data layers were prepared using GIS Map software and the latest set of tables with predominant cultivars that were cultured in each region. Results showed that spring type was 65.5% of whole and their diversity depending on the coldness of winter. Spring type cultivars mainly adapted to south warm and moderate climates where average January temperature was above 4 oC. On the contrary, winter type adapted to areas of average January temperature from -7 oC to 4 oC. With determining genotypes based on of these traits, breeders will enable to lead segregation generations to better compatibility.

To evaluate the role of potassium on salt tolerance of two durum wheat varieties, Behrang and Yavaros, a pot experiment was carried out as factorial experiment based on completely randomized design with three replications in College of Agriculture, Shahid Chamran University of Ahvaz, in 2013-2014. The experimental treatments were control, NaCl 150 mM, NaCl 150 mM together with two levels of 300 and 450 mg of potassium sulfate per 1 kg soil and two levels of 30 and 45 mg of potassium nano chelate 27% per 1 kg soil. Results showed that salinity stress lead to decreasing 68%, 51%, 58%, 22%, 15% and 61% of the grain yield, biological yield, stomatal conductance, greenness index, relative water content and K+ concentration, respectively, and increasing 3.9 fold of the Na+ concentration of flag leaf compared with control treatment. In contrast, the application of different types of potassium under salinity condition alleviated the negative effects of salt stress on grain yield, biological yield, stomatal conductance, greenness index, relative water content and K+ concentration (25, 27, 22, 36, 7 and 35%, respectively), and was caused the lower Na+ accumulation (2.8 fold) compared with control. The variety responses to different levels of potassium were different, so that the second levels of potassium sulfate and nano potassium in Behrang variety caused to decrease the grain yield, while the grain yield of Yavaros variety was not affected. Results showed that Behrang variety was more tolerant than Yavaros in response to salinity. Generally, the application of potassium under salinity conditions was caused to maintain photosynthesis by adjusting the osmotic potential and relative water content and increasing the stomatal conductance as well as preventing loss chlorophyll, hereby reduces the salinity effects on yield performance of the durum wheat.

To evaluate the effect of seed priming on plant establishment and to determine the optimum planting date and plant density of silage corn, SC 704, in summer late planting, an experiment was carried out as split-split plot based on randomized complete block design with four replications in Agriculture Research Center of Gharahkeil, Qaemshahr, Mazandaran Province, Iran, during two years, 2010 and 2011. The experimental factors were including two levels (27 July and 7 August) of planting dates as main plots, two levels of plant density (7 and 9 plants per m2) as sub-plots and four levels of seed priming (pure water, PEG-8000, KNO3 and control) as sub-sub-plots. Results showed that forage dry yield and ratio of ear to total dry weight were higher in 2010 than 2011. With the delayed planting, forage dry yield and ratio of ear to total dry weight had decreased 31.7% and 18.2%, respectively. Furthermore, forage dry yield had increased 21.4% with the increasing of plant density. The seed priming with PEG also increased the ratio of ear to total dry weight. In total, results of this research indicated that the seed priming with PEG using late summer planting in August and density of 90000 plants per ha is possible to produce the high quality forage in silage corn.