• Authors:
    • Pompa, M.
    • Giuzio, L.
    • Ficco, D. B. M.
    • Borrelli, G. M.
    • Cattivelli, L.
    • Flagella, Z.
  • Source: Cereal Research Communications
  • Volume: 39
  • Issue: 4
  • Year: 2011
  • Summary: Durum wheat (Triticum turgidum L. Desf.) is a species well adapted to the Mediterranean environments where salt stress due to seawater intrusion is an increasing problem. The purpose of this study was to deep insight into the relationships among physiological, productive and qualitative aspects under salinity, being these aspects still poorly investigated in durum wheat. In 2004-2005 crop season 10 durum wheat genotypes of different origin and breeding time were grown in a naturally-lit polycarbonate greenhouse under three irrigation water salinity levels (0.9, 6.0 and 12.0 dS m -1). A complete randomized block design with three replications was adopted. The osmotic damage was evaluated by estimating relative water content (RWC), leaf water potential (Phi w) and osmotic potential at full turgor (Phi pi100). The toxic damage to the plants was evaluated by measuring Na + accumulation and Na +/K + ratio in the leaves. Differences in yield performance were evaluated by assessing the main yield components and some qualitative traits, carotenoid pigment and protein content and Sedimentation test in sodium dodecyl sulphate. A significant effect of genotype, salt stress and of their interaction on all the characters was observed. Durum wheat genotypes generally showed a moderate tolerance to salt stress. The genotype performance was dependent on stress level and RWC maintenance. Osmotic adjustment and low sodium accumulation were found to play a key role in salt tolerance. An improvement in the grain quality characters on increasing salinity level, consistently with a yield decrease, was observed.
  • Authors:
    • Tabatabaei, B. E. S.
    • Maibody, S. A. M. M.
    • Arzani, A.
    • Golabadi, M.
    • Mohammadi, S. A.
  • Source: Euphytica
  • Volume: 177
  • Issue: 2
  • Year: 2011
  • Summary: Grain yield and yield components are the main important traits involved in durum wheat ( Triticum turgidum L.) improvement programs. The purpose of this research was to identify quantitative trait loci (QTL) associated with yield components such as 1000 grain weight (TGW), grain weight per spike (GWS), number of grains per spike (GNS), spike number per m 2 (SN), spike weight (SW), spike harvest index (SHI) and harvest index (HI) using microsatellite markers. Populations of F 3 and F 4 lines derived from 151 F 2 individuals developed from a cross between Oste-Gata, a drought tolerant, and Massara-1, a drought susceptible durum wheat genotypes, were used. The populations were evaluated under four environmental conditions including two irrigation regimes of drought stress at terminal growth stages and normal field conditions in two growing seasons. Two hundred microsatellite markers reported for A and B genomes of bread wheat were used for parental polymorphism analysis and 30 polymorphic markers were applied to genotype 151 F 2:3 families. QTL analysis was performed using genome-wide single marker regression analysis (SMA) and composite interval mapping (CIM). The results of SMA revealed that about 20% of the phenotypic variation of harvest index and TGW could be explained by Xcfd22-7B and Xcfa2114-6A markers in different environmental conditions. Similarly, Xgwm181-3B, Xwmc405-7B and Xgwm148-3B and marker Xwmc166-7B were found to be associated with SHI and GWS, respectively. A total of 20 minor and major QTL were detected; five for TGW, two for GWS, two for GNS, three for SN, five for HI, two for SHI and one for SW. The mapped QTL associated with ten markers. Moreover, some of these QTL were prominent and stable under drought stress and non drought stress environments and explained up to 49.5% of the phenotypic variation.
  • Authors:
    • Ganji, A.
    • Mousavi, S. F.
    • Lee, T. S.
    • Soom, M. A. M.
    • Salemi, H.
    • KamilYusoff, M.
  • Source: African Journal of Agricultural Research
  • Volume: 6
  • Issue: 10
  • Year: 2011
  • Summary: Simulation models that clarify the effects of water on crop yield, are useful tools for improving farm-level water management and optimizing water use efficiency. The main purpose of deficit irrigation is high water productivity with less water supply to plants. In this research, the potential of AquaCrop model in deficit irrigation practice for winter wheat, the main agronomic crop in Gavkhuni river basin, Isfahan province, Iran, was studied. The results of reliability indices such as RMSE, d, E, CRM and deviation percent were 2.31 to 5.63, 0.97 to 1.00, 93 to 99, -0.15 to 0.016 and -0.70 to 12.00% respectively, and showed that, the model overestimated the simulated parameters compared with field data. This difference was more obvious in deficit irrigation treatments. The model provided excellent simulations of canopy cover, grain yield and water productivity. Considering only drought stress and neglecting other stresses such as salinity is the most important limitation of AquaCrop model. In this study, water productivity for the studied crop was in the range of 0.91 to 1.49 kg m -3 and its maximum value was in 40% deficit irrigation treatment. A second-order, yield-water function, obtained in this study is recommended for winter wheat crop. Also, the sensitivity analysis of AquaCrop model was carried out for winter wheat in this arid area in central Iran.
  • Authors:
    • Joshi, A. K.
    • Dixon, J.
    • Waddington, S. R.
    • Li, X.Y.
    • Vicente, M. C. de
  • Source: Food Security
  • Volume: 3
  • Issue: 1
  • Year: 2011
  • Summary: Variation in water availability is a major source of risk for agricultural productivity and food security in South Asia. Three hundred and thirty expert informants were surveyed during 2008-09 to determine the relative importance of drought and water-related constraints compared with other constraints limiting the production of four major food crops (wheat, rice, sorghum, chickpea) in five broad-based South Asian farming systems. Respondents considered drought an important constraint to crop yield in those farming systems that are predominantly rainfed, but associated it with low yield losses (well below 10% of all reported losses) for crops in farming systems with well-developed irrigation. In these systems, other water-related constraints (including difficult access to sufficient irrigation water, the high cost of irrigation, poor water management, waterlogging and flooding of low-lying fields) were more important. While confirming the importance of drought and water constraints for major food crops and farming systems in South Asia, this study also indicated they may contribute to no more than 20-30% of current yield gaps. Other types of constraint, particularly soil infertility and the poor management of fertilizer and weeds for the cereals, and pests and diseases for chickpea, contributed most yield losses in the systems. Respondents proposed a wide range of interventions to address these constraints. Continued investments in crop-based genetic solutions to alleviate drought may be justified for food crops grown in those South Asian farming systems that are predominantly rainfed. However, to provide the substantial production, sustainability and food security benefits that the region will need in coming decades, the study proposed that these be complemented by other water interventions, and by improvements to soil fertility for the cereals and plant protection with chickpea.
  • Authors:
    • Bueckert, R.
    • Gan. Y.T.
    • Liu, L. P.
    • Rees, K. van
  • Source: Field Crops Research
  • Volume: 122
  • Issue: 3
  • Year: 2011
  • Summary: Oilseed and pulse crops have been increasingly used to diversify cereal-based cropping systems in semiarid environments, but little is known about the root characteristics of these broadleaf crops. This study was to characterize the temporal growth patterns of the roots of selected oilseed and pulse crops, and determine the response of root growth patterns to water availability in semiarid environments. Canola ( Brassica napus L.), flax ( Linum usitatissimum L.), mustard ( Brassica juncea L.), chickpea ( Cicer arietinum L.), field pea ( Pisum sativum L.), lentil ( Lens culinaris), and spring wheat ( Triticum aestivum L.) were tested under high- (rainfall+irrigation) and low- (rainfall only) water availability conditions in southwest Saskatchewan, in 2006 and 2007. Crops were hand-planted in lysimeters of 15 cm in diameter and 100 cm in length that were installed in the field prior to seeding. Roots were sampled at the crop stages of seedling, early-flower, late-flower, late-pod, and physiological maturity. On average, root length density, surface area, diameter, and the number of tips at the seedling stage were, respectively, 41, 25, 14, and 110% greater in the drier 2007 than the corresponding values in 2006. Root growth in all crops progressed rapidly from seedling, reached a maximum at late-flower or late-pod stages, and then declined to maturity; this pattern was consistent under both high- and low-water conditions. At the late-flower stage, root growth was most sensitive to water availability, and the magnitude of the response differed between crop species. Increased water availability increased canola root length density by 70%, root surface area by 67%, and root tips by 79% compared with canola grown under low-water conditions. Water availability had a marginal influence on the root growth of flax and mustard, and had no effect on pulse crops. Wheat and two Brassica oilseeds had greater root length density, surface area and root tips throughout the entire growth period than flax and three pulses, while pulse crops had thicker roots with larger diameters than the other species. Sampling roots at the late-flower stage will allow researchers to capture best information on root morphology in oilseed and pulse crops. The different root morphological characteristics of oilseeds, pulses, and wheat may serve as a science basis upon which diversified cropping systems are developed for semiarid environments.
  • Authors:
    • Bueckert, R.
    • Gan, Y. T.
    • Liu, L. P.
    • Rees, K. van
  • Source: Field Crops Research
  • Volume: 122
  • Issue: 3
  • Year: 2011
  • Summary: Root distribution patterns in the soil profile are the important determinant of the ability of a crop to acquire water and nutrients for growth. This study was to determine the root distribution patterns of selected oilseeds and pulses that are widely adapted in semiarid northern Great Plains. We hypothesized that root distribution patterns differed between oilseed, pulse, and cereal crops, and that the magnitude of the difference was influenced by water availability. A field experiment was conducted in 2006 and 2007 near Swift Current (50°15′N, 107°44′W), Saskatchewan, Canada. Three oilseeds [canola ( Brassica napus L.), flax ( Linum usitatissimum L.), mustard ( Brassica juncea L.)], three pulses [chickpea ( Cicer arietinum L.), field pea ( Pisum sativum L.), lentil ( Lens culinaris)], and spring wheat ( Triticum aestivum L.) were hand-planted in lysimeters of 15 cm in diameter and 100 cm in length which were pushed into soil with a hydraulic system. Crops were evaluated under low- (natural rainfall) and high- (rainfall+irrigation) water conditions. Vertical distribution of root systems was determined at the late-flowering stage. A large portion (>90%) of crop roots was mainly distributed in the 0-60 cm soil profile and the largest amount of crop rooting took place in the top 20 cm soil increment. Pulses had larger diameter roots across the entire soil profile than oilseeds and wheat. Canola had 28% greater root length and 110% more root tips in the top 10 cm soil and 101% larger root surface area in the 40 cm soil under high-water than under low-water conditions. In 2007, drier weather stimulated greater root growth for oilseeds in the 20-40 cm soil and for wheat in the 0-20 cm soil, but reduced root growth of pulses in the 0-50 cm soil profile. In semiarid environments, water availability did not affect the vertical distribution patterns of crop roots with a few exceptions. Pulses are excellent "digging" crops with a strong "tillage" function to the soil due to their larger diameter roots, whereas canola is more suitable to the environment with high availability of soil water that promotes canola root development.
  • Authors:
    • Risaliti, R.
    • Antichi, D.
    • Barberi, P.
    • Sapkota, T. B.
    • Mazzoncini, M.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: No-tillage, N fertilization and cover crops are known to play an important role in conserving or increasing SOC and STN but the effects of their interactions are less known. In order to evaluate the single and combined effects of these techniques on SOC and STN content under Mediterranean climate, a long term experiment started in 1993 on a loam soil (Typic Xerofluvent) in Central Italy. The experimental variants are: conventional tillage (CT) and no-tillage (NT), four N fertilization rates (N0, N1, N2 and N3) and four soil cover crop (CC) types (C - no cover crop; NL - non-legume CC; LNL - low nitrogen supply legume CC, and HNL - high nitrogen supply legume CC). The nitrogen fertilization rates (N0, N1, N2 and N3) were: 0, 100, 200, 300 kg N ha(-1) for maize (Zea mays, L); 0, 60, 120,180 kg N a(-1) for durum wheat (Triticum durum Desf.); 0, 50, 100, 150 kg N ha(-1) for sunflower (Helianthus annuus L.). From 1993 to 2008, under the NT system the SOC and STN content in the top 30 cm soil depth increased by 0.61 and 0.04 Mg ha(-1) year(-1) respectively. In the same period, the SOC and STN content under the CT system decreased by a rate of 0.06 and 0.04 Mg ha(-1) year(-1) respectively. During the experimental period, N1, N2 and N3 increased the SOC content in the 0-30 cm soil layer at a rate of 0.14, 0.45 and 0.49 Mg ha(-1) year(-1). Only the higher N fertilization levels (N2 and N3) increased STN content, at a rate of 0.03 and 0.05 Mg ha(-1) year(-1). NL, LNL and HNL cover crops increased SOC content by 0.17, 0.41 and 0.43 Mg C ha(-1) year(-1) and -0.01, +0.01 and +0.02 Mg N ha(-1) year(-1). Significant interactions among treatments were evident only in the case of the N fertilization by tillage system interaction on SOC and STN concentration in the 0-10 cm soil depth in 2008. The observed SOC and STN variations were correlated to C returned to the soil as crop residues, aboveground cover crop biomass and weeds (C input). We conclude that, under our Mediterranean climate, it is easier to conserve or increase SOC and STN by adopting NT than CT. To reach this objective, the CT system requires higher N fertilization rates and introduction of highly productive cover crops. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Middleton, A. B.
    • Bremer, E.
    • McKenzie, R. H.
    • Pfiffner, P. G.
    • Woods, S. A.
  • Source: Canadian Journal of Plant Science
  • Volume: 91
  • Issue: 2
  • Year: 2011
  • Summary: High crop productivity is essential for irrigated crops and may be strongly affected by decisions of seeding date and rate. An irrigated field experiment was conducted at two locations in southern Alberta for 4 yr to compare the impact of seeding date and rate on productivity and quality of nine cereal crops and two oilseed crops. Seeding rate was only evaluated on one date in late April or early May, when maximum yields were expected. Delayed seeding reduced crop yields by 0.6 to 1.7% per day after the end of April: flax ( Linum usitatissimum L.) ≤ CWRS wheat ( Triticum aestivum L.), feed triticale (* Triticosecale W.) ≤ CPS or SWS wheat ≤ triticale or barley ( Hordeum vulgare L.) silage ≤ durum ( T. turgidum L.), feed or malt barley
  • Authors:
    • McSorley, R.
  • Source: Nematropica
  • Volume: 41
  • Issue: 2
  • Year: 2011
  • Summary: Studies that utilized rotation crops for management of root-knot nematodes in the southeastern United States were examined to evaluate the overall performance of rotation crops. In general, nematode-susceptible crops that followed effective rotation crops produced yields and supported nematode numbers similar to those obtained on crops treated with most standard nematicides. Fumigation with methyl bromide was an exception, and resulted in low nematode numbers up to the end of the susceptible target crop, whereas nematode numbers recovered following rotation crops. Performance of rotation crops was similar to clean fallow in most studies, and there was little evidence that rotation crops could suppress nematode numbers below levels obtained after clean fallow. Large reductions in nematode numbers often were achieved following rotation crops. In sites with relatively low initial population levels before rotation crops were used, effective rotation crops sometimes maintained relatively low nematode numbers through the following susceptible target crop, and nematode recovery was not observed until the second year of the rotation sequences. Where practical, very long rotations such as bahiagrass pastures were often effective in preventing increase in nematode numbers on subsequent susceptible crops. Rehabilitation of heavily infested sites is difficult, could require several years of rotation crops, and the benefit gained may last only through one susceptible crop.
  • Authors:
    • Moreno, F.
    • Muñoz-Romero, V.
    • López-Bellido, L.
    • López-Bellido, R. J.
    • Melero,S.
    • Murillo, J. M.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: Studies of the impacts of the interactions of soil agricultural practices on soil quality could assist with assessment of better management to establish sustainable crop production system. The main objective was to determine the long-term effects of tillage system, crop rotation and N fertilisation on soil total N and organic C (SOC), labile fractions of organic matter (water soluble carbon, WSC, and active carbon, AC), nitrate content, and soil enzymatic activities (dehydrogenase (DHA), beta-glucosidase (Glu) and alkaline phosphatase (AP)) at four different soil depths (0-5, 5-10, 10-30 and 30-50 cm), in a Mediterranean dryland Vertisol in SW Spain. Tillage systems were conventional tillage (CT) and no tillage (NT). Crop rotations were wheat-sunflower (WS), wheat-chickpea (WC), wheat-faba bean (WFb), wheat-fallow (WF) and continuous wheat (WW). Nitrogen fertiliser rates were 0, 50 and 150 kg N ha(-1). The different crop rotation systems had a great influence in soil C and N fractions and enzymatic activities. In general, the SOC. total N. WSC, and beta-glucosidase contents were higher in the no tillage system than in conventional tillage system in the wheat-wheat and in the wheat-faba bean rotations at upper layer (0-5 cm), while the lowest ones were obtained in the wheat-fallow rotation in both tillage systems. Carbon and N fractions, calculated by volumetric soil, showed an increase with depth in both tillage systems and in all crop rotations, which could be related to the increase of soil bulk density and soil mass with depth. The highest N fertiliser rate increased most of soil variables, especially nitrate content at deeper layers, thereby precautions should be taken with long-term N fertilisation to avoid leaching of nitrates below the tillage layer. With the exception of wheat-fallow rotation, slightly greater grain and above-ground biomass yields were obtained for wheat in NT, especially at 150 kg N ha(-1). Combination of NT with any biannual rotation except fallow could be an adequate sustainable management in order to improve soil quality of Vertisols, under our conditions. (C) 2011 Elsevier B.V. All rights reserved.