Browsing by Author "Keshavarz-Afshar, Reza"

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Energy balance & greenhouse gas emissions of dryland camelina as influenced by tillage and nitrogen
(2015-11) Keshavarz-Afshar, Reza; Mohammed, Yesuf Assen; Chen, Chengci
Despite the great potential of camelina (Camelina sativa L. Crantz) as a promising biofuel feedstock, in-farm energy flow of the crop and its associated environmental impacts has not received sufficient attention from researchers. In order to assess net energy gain and to identify energy saving and environmental friendly production operations, a two year study was conducted at central Montana. We investigated the effects of tillage method (CT (conventional tillage) vs. NT (no-tillage)) and N (nitrogen) fertilizer rate (0, 45, 90 kg N ha−1) on energy balance and GHG (greenhouse gas emission) of dryland camelina production. Results indicated that energy input and GHG emission were 5 and 8% lower in NT than in CT. Application of 45 and 90 kg N ha−1 increased camelina energy input by 186 and 365%, while increased energy output by only 21 and 64%, respectively. There was no significant difference in net energy gain in response to N fertilization, but lower energy efficiency in response to higher N inputs. Averaged across tillage systems, the GHG emission was 32.0 kg C eq ha−1 with 0 N applied, and the GHG emission increased by 206 and 389% when 45 and 90 kg N ha−1 was applied. Overall, N fertilizer had the biggest share in total energy input. Averaged over all experimental treatments, 14,945 MJ ha−1 net energy was obtained from camelina crop in this study which shows the potential of this crop as a bioenergy feedstock. Our result showed that implementation of NT is strongly recommendable for camelina production in this region. Moreover, improvement of N use efficiency has the highest priority to improve energy performance and reduce GHG emissions in camelina production.
High-density genetic map construction and QTLs identification for plant height in white jute (Corchorus capsularis L.) using specific locus amplified fragment (SLAF) sequencing
(2017-05) Tao, Aifen; Huang, Long; Wu, Guifen; Keshavarz-Afshar, Reza; Qi, Jianmin; Xu, Jiantang; Fang, Pingping; Lin, Lihui; Zhang, Liwu; Lin, Peiqing
BACKGROUND Genetic mapping and quantitative trait locus (QTL) detection are powerful methodologies in plant improvement and breeding. White jute (Corchorus capsularis L.) is an important industrial raw material fiber crop because of its elite characteristics. However, construction of a high-density genetic map and identification of QTLs has been limited in white jute due to a lack of sufficient molecular markers. The specific locus amplified fragment sequencing (SLAF-seq) strategy combines locus-specific amplification and high-throughput sequencing to carry out de novo single nuclear polymorphism (SNP) discovery and large-scale genotyping. In this study, SLAF-seq was employed to obtain sufficient markers to construct a high-density genetic map for white jute. Moreover, with the development of abundant markers, genetic dissection of fiber yield traits such as plant height was also possible. Here, we present QTLs associated with plant height that were identified using our newly constructed genetic linkage groups. RESULTS An F8 population consisting of 100 lines was developed. In total, 69,446 high-quality SLAFs were detected of which 5,074 SLAFs were polymorphic; 913 polymorphic markers were used for the construction of a genetic map. The average coverage for each SLAF marker was 43-fold in the parents, and 9.8-fold in each F8 individual. A linkage map was constructed that contained 913 SLAFs on 11 linkage groups (LGs) covering 1621.4 cM with an average density of 1.61 cM per locus. Among the 11 LGs, LG1 was the largest with 210 markers, a length of 406.34 cM, and an average distance of 1.93 cM between adjacent markers. LG11 was the smallest with only 25 markers, a length of 29.66 cM, and an average distance of 1.19 cM between adjacent markers. \'SNP_only\' markers accounted for 85.54% and were the predominant markers on the map. QTL mapping based on the F8 phenotypes detected 11 plant height QTLs including one major effect QTL across two cultivation locations, with each QTL accounting for 4.14-15.63% of the phenotypic variance. CONCLUSIONS To our knowledge, the linkage map constructed here is the densest one available to date for white jute. This analysis also identified the first QTL in white jute. The results will provide an important platform for gene/QTL mapping, sequence assembly, genome comparisons, and marker-assisted selection breeding for white jute.
Intensification of Dryland Cropping Systems for Bio-feedstock Production: Energy Analysis of Camelina
(2015-12) Keshavarz-Afshar, Reza; Chen, Chengci
Camelina (Camelina sativa L. Crantz), as a bioenergy and bio-product feedstock, may be grown as a rotation crop in the wheat-based cropping system to increase land use efficiency in the Northern Great Plains (NGP). In this study, which was conducted from 2008 to 2011 in central Montana, we evaluated the energy balance of three 2-year cop rotational sequences that included camelina-winter wheat (Triticum aestivum L.) (CAM-WW) and barley (Hordeum vulgare L.)-winter wheat (BAR-WW) compared with a traditional fallow-winter wheat (FAL-WW) rotation. Results indicated that 52 and 57 % more energy input was invested in CAM-WW and BAR-WW compared to FAL-WW system (9182 MJ haâˆ’1), respectively. In all rotations, nitrogen fertilizer was the most energy-consuming input and accounted for 76, 68, and 69 % of the total energy used in wheat, barley, and camelina production, respectively. Averaged over 3 years, CAM-WW and BAR-WW systems yielded 34 and 29 % greater gross energy output compared with FAL-WW. The CAM-WW and BAR-WW also outperformed FAL-WW by 30 and 6 % in terms of net energy output. No significant differences in energy efficiency were found between the FAL-WW and CAM-WW systems. Taking into account of the greater net energy as well as similar values of energy use efficiency, the CAM-WW system performed better than the traditional FAL-WW system under rainfed conditions in central Montana. There is a good potential to improve the energy efficiency of the CAM-WW cropping system (by more than 26 %) through refinement of agronomic practices, mainly nitrogen fertilization and herbicide application, which can further enhance the sustainability of camelina feedstock production.
Lentil Response to Nitrogen Application and Rhizobia Inoculation
(2016-11) Huang, Jinwen; Keshavarz-Afshar, Reza; Chen, Chengci
Lentils (Lens culinaris L.) are an important component of the dryland farming systems in the western USA. Optimum nitrogen (N) management can enhance yield and quality of lentils. We conducted a field (at two locations, one with previous history of lentil and the other one without lentil history) and a greenhouse study to evaluate response of lentil to the application of rhizobium inoculant and starter N (control, 22 kg N ha(-1) in the form of urea [U], 22 kg N ha(-1) in the form of slow-release or environmentally safe nitrogen [ESN], and 22 kg N ha(-1) U + 22 kg N ha(-1) ESN). In both, the field and the laboratory studies, lentil yield did not respond positively to the experimental treatments. Lentil average yield was 1216 and 1420 kg ha(-1) at the field condition. In this rain-fed system, lentil yield was mainly limited by moisture availability, and the application of an external N did not contribute to the yield enhancement. Both of these treatments, however, increased protein content. Compared to the control, the application of rhizobium plus U and ESN enhanced protein content by about 34% (from 23.1 to 30.9%). The application of U+ ESN also considerably increased postharvest residual nitrate (NO3)-N in the soil, which can be easily leached and creates environmental pollution. Briefly, the application of U+ ESN increases lentil protein content, but more efforts are needed to optimize N management in lentils in order to reduce the environmental concerns in the shallow soil.
Nitrogen Fertilizer and Seeding Rate Influence on Grain and Forage Yield of Dual-Purpose Barley
(2016-05) Hajighasemi, S.; Keshavarz-Afshar, Reza; Chaichi, M. R.
Clipping fall-sown cereals provides a good source of high-quality forage during late winter. Farmers usually use more inputs, including fertilizers and seed, in dual-purpose systems compared with grain-only systems. A 2-yr field study was conducted in Karaj, Iran, to evaluate the effects of nitrogen (N) rates (0, 50, 100, 150 kg N ha−1) and seeding rates (400, 600, 800 seed m−2) on forage and grain yields of two barley (Hordeum vulgare L.) cultivars (Fasih and CB 744) in grain-only and dual-purpose systems. Fasih and CB 744 grain yields in the grain-only system were 2996 and 3250 kg ha−1, respectively (averaged over experimental treatments). Forage removal in the dual-purpose system resulted in 25% grain yield penalty. Despite the lower grain yield, the economic return of the dual-purpose system was considerably greater due to the high price of forage during late winter in the region. Grain yield response to N was linear in the grain-only system, but the trend was not significant in the dual-purpose system. In both production systems, grain yield response to seeding rate was quadratic, and the highest yields of both cultivars (2534 and 3192 kg ha−1 for Fasih and CB 744, respectively) were obtained from 600 seed m−2. In both production systems, 600 seed m−2 and 100 kg N ha−1 were optimum for grain and forage production. Our results showed considerably higher revenue in the dual-purpose system compared with the grain-only system in this region. Moreover, no additional inputs of N and seed are required for dual-purpose barley than those usually used in a grain-only system.
Nutrient requirements of camelina (Camelina sativa L. Crantz) for biodiesel feedstock in central Montana
(2017-01) Mohammed, Yesuf Assen; Chen, Chengci; Keshavarz-Afshar, Reza
Camelina (Camelina sativa L. Crantz) shows potential to provide an alternative renewable energy source and enhance crop diversification in temperate semiarid regions. Information on the effect of N, P, K, and S on yield and quality of camelina for biodiesel feedstock in the northern Great Plains (NGP) of the United States is limited. The objective of this experiment was to determine the effects of the above nutrients on seed and oil yields, test weight, oil concentration and agronomic nitrogen use efficiency (ANUE) of camelina on a clay loam soil in central Montana. Results showed that fertilizer treatments significantly affected seed yield, oil concentration and oil yield of camelina. The seed and oil yields ranged from 677 to 1306 kg ha–1and from 234 to 445 kg ha–1, respectively. Although the highest seed and oil yields were obtained from the application of 134–22–22–28 kg ha–1 N–P2O5–K2O–S, they were statistically in the same group with yields achieved from the application of only 45 kg ha–1 N. Application of P and S fertilizers increased camelina seed yield compared with the control treatment. There was no response to K fertilization. Simultaneous application of N and S did not show synergistic effects in enhancing ANUE. The ANUE reduced with increasing N application rates. From trend analysis, application of 60 kg ha–1 N produced agronomic maximum seed and oil yields. Therefore, optimizing camelina seed and oil yields production with regard to nutrient management using current variety should focus on N fertilization.