• Authors:
    • Wellings, C.
  • Source: Euphytica
  • Volume: 179
  • Issue: 1
  • Year: 2011
  • Summary: Stripe rust, caused by Puccinia striiformis, has been an important disease of wheat, barley, rye, triticale and certain graminaceous hosts for centuries. The significance of the disease on cultivated cereals has waxed and waned according to the vagaries of climate, inoculum levels and susceptible varieties. A progressive understanding of pathogen biology has revealed levels of specialisation between and within host groups, and these had varying impacts on the hosts concerned. The most economically important form is P. striiformis f. sp. tritici ( Pst), the causal pathogen of stripe (yellow) rust of wheat, which is the major focus of this paper. The recent discovery of the perfect stage of Pst on Berberis spp. will encourage further work to uncover the potential importance of the sexual stage in pathogen biology in regions where Berberis spp. occur. A review of the evolution of pathotypes within Pst over the past 50 years reveals recurrent pandemics emanating from a combination of specific virulence in the pathogen population, wide scale cultivation of genetically similar varieties, and agronomic practices that led to high yield potential. When these factors operate in concert, regional stripe rust epidemics have proven to be dramatic, extensive and serious in terms of the magnitude of losses and the economic hardships endured. A review of these epidemics suggests that little progress has been made in containing the worst effects of epidemics. The current status of stripe rust was gauged from a survey of 25 pathologists and breeders directly associated with the disease. It was evident that Pst remains a significant threat in the majority of wheat growing regions of the world with potential to inflict regular regional crop losses ranging from 0.1 to 5%, with rare events giving losses of 5-25%. Regions with current vulnerability include the USA (particularly Pacific North West), East Asia (China north-west and south-west), South Asia (India, Pakistan, Nepal), Oceania (Australia, New Zealand), East Africa (Ethiopia, Kenya), the Arabian Peninsula (Yemen) and Western Europe (east England). The resources deployed to contain the worst effects of Pst will need to find a balance between training a new generation of breeders and pathologists in host-pathogen genetics, and an investment in infrastructure in IARCs and NARs.
  • Authors:
    • Oberforster, M.
    • Hammerl, S.
    • Zechner, E.
  • Source: Tagungsband der 61. Jahrestagung der Vereinigung der Pflanzenzuchter und Saatgutkaufleute Osterreichs, 23-25 November 2010, Raumberg-Gumpenstein, Osterreich. Ertrag vs. Qualitat bei Getreide, Ol und Eiweisspflanzen. Wheat stress
  • Year: 2011
  • Summary: Since 1903 cereal breeding takes place at Edelhof near Zwettl, Lower Austria. The main focus lies on the breeding of top-quality wheat for Europe, high-yielding wheat with medium quality, two-rowed winter barley, spring barley with a high percentage of plump seeds, early maturing quality oats, open-pollinating rye and varieties for organic farming. With the directive 2009/28/EG and the installation of a bio-ethanol plant in Austria, breeders interest in selecting cereals for ethanol production awaked. This means in particular field selection, investments in quality analyses and targeted projects, and furthermore the implementation of a new breeding programme (parallel to bread cereal breeding). From crossing to variety release several years pass by. Meanwhile, cereal breeders had to realize that from the bio-ethanol market there is no special interest in varieties specific for this purpose.
  • Authors:
    • Tanigawa, T.
    • Yamamoto, T.
    • Al-Busaidi, A.
    • Rahman, H.
  • Source: Irrigation and Drainage
  • Volume: 60
  • Issue: 4
  • Year: 2011
  • Summary: Water stress is the primary environmental factor that limits cereal production in Mediterranean environments, where barley ( Hordeum vulgare L.) is one of the main crops. This investigation aimed at evaluating the effects of zeolite on barley growth under subsurface drip irrigation, subjected to water and heat stress. A sand dune soil was amended with Ca-type zeolite and irrigated every 2nd, 3rd, 4th and 5th day. The results showed that zeolite application significantly increased water-holding capacity of the soil and improved plant growth. Using subsurface irrigation with zeolite amendment helped to reduce water evaporation, kept more water in lower horizons, encouraged salt leaching, and the plants used water more efficiently. Plant growth parameters showed significant differences among treatments and were negatively affected by heat and water stress conditions. High temperatures caused accelerated evapotranspiration, water stress in plants and faster depletion of water from the root zone, causing substantial water loss and inducing water deficit conditions in plants. Using subsurface irrigation poses a better option for the reduction of evaporation and achieving higher water use efficiency. Application of zeolite together with subsurface irrigation may provide favorable conditions for crop production in water-scarce areas under warm environments.
  • Authors:
    • Tadesse, D.
    • Sisay, F.
    • Mitiku, H.
    • Solomon, H.
    • Araya, A.
  • Source: Momona Ethiopian Journal of Science
  • Volume: 3
  • Issue: 1
  • Year: 2011
  • Summary: An experiment was carried out in 2010 at Mekelle, in northern Ethiopia, to measure the evapotranspiration, to estimate barley crop coefficient ( kc), and to evaluate the water productivity taking into account the major crops grown under the present pond irrigation system. Four locally made lysimeters were installed in the middle of barley field to measure barley evapotranspiration. The single crop coefficient approach was used to estimate barley crop coefficient. The average seasonal evapotranspiration of barley was 375 mm which is similar to many other cereal crops in the region. The single crop coefficient values for early, vegetative, mid and late crop stages were 0.6-0.8, 0.6-1.0; 1.0-1.05 and 0.3-0.4 respectively. The result showed that these crop coefficient values obtained in this experiment were similar to the crop coefficient values obtained in the past except for kc initial. Therefore, the assumption that local barley crop coefficient values differ from that of the documented values was incorrect. Furthermore, the major reason for mismanagement of irrigation water in barley fields was not due to use of wrong crop coefficient values but could be due to inadequate irrigation technical skill and knowledge of the farmer. The average economic water productivity (EWP) of barley for the very wet, wet, normal, dry and very dry seasons scenario were 0.99, 0.7, 0.65, 0.57, and 0.44 USD m -3, respectively, whereas the corresponding crop water productivity (CWP) values for grain were 1.53, 1.08, 1.0, 0.88 and 0.68 kg m -3, respectively. The EWP and CWP of barley were compared with onion and tomato under pond water irrigation at the five climatic scenarios. The crop water productivity for tomato and onion were 85-87% and 76-78% higher than that of barley, respectively. The corresponding economic water productivity for tomato and onion were 87-89% and 81-82% higher than that of barley, respectively. We concluded that growing tomato and onion would bring more income or yield per m 3 of pond water supplied than growing barley. The implication is that as supply and demand determines the price of products, farmers and extension workers need to balance the crop area coverage per irrigation scheme so that undesirable price falls and rises could be avoided. Evaluation of crops based on their water productivity would improve the productivity of irrigation schemes and ultimately improve food security in the arid and semi-arid areas where water scarcity is critical problem and irrigation is a necessity for crop production.
  • Authors:
    • Asgharzade, A.
    • Tavassoli, A.
    • Esmaeilian, Y.
    • Babaeian, M.
    • Sadeghi, M.
  • Source: Scientific Research and Essays
  • Volume: 6
  • Issue: 17
  • Year: 2011
  • Summary: Barley is a cool-weather cereal grain primarily produced on dryland farms in Sistan region. In order to study the effect of different proportions of manure and chemical fertilizer and water stress on grain yield and grain nutrient content in barley an experiment was conducted as split plot randomized complete block design with three replications in research field of Zabol University, 2009. Water stress treatments consisted of: water stress in grain filling stage (S 1) and control (S 2) as the main factor and different proportions of manure and chemical fertilizer treatment consisted of: 100% manure (N 1), 100% chemical fertilizer (N 2), 50% manure+50% chemical fertilizer (N 3), 75% manure+25% chemical fertilizer (N 4) and control (N 5) as sub factor in this experiment. Results illustrated that the effect of drought stress in grain filling stage treatment on all grain yield and yield components with the exception of ear weight, were significant. Drought stress in grain filling stage strongly decreased grain yield but its effect was not very strong on another traits. With the exception of grain number/ear and ear weight, fertilizer treatments had significant effect on grain yields and yield components. Grain nutrient content not affected by water stress but among different proportions of fertilizer treatments, 100% manure (N 1) caused to increase of these elements in grain.
  • Authors:
    • Sanjani, S.
    • Bannayan, M.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Climate variability and weather extremes are principal sources of fluctuations of annual productivity of many crops in arid and semi-arid environments. Temperature and precipitation are the major weather variables that determine the variability of crop yields. In this study, the relationship between weather descriptors and major irrigated crops yield were assessed for Khorasan province in northeast of Iran. Long term daily weather (1984-2007) and crop yield (wheat, barley, sugarbeet, cotton, potato, chickpea, alfalfa) data were analyzed with simple correlation analysis and also the iterative chi-square analysis identified relationships of low and high wheat yield years to maximum and minimum air temperatures within each region. Our results indicated that association between various crop yield and descriptors varied in different study location. As in Bojnourd located in the north of Khorasan yields of the crops studied did not correlate with temperature indicators, whereas in Birjand the relationship between temperature descriptors and crop yields were strong. Correlation between growing season precipitation and wheat, barley, chickpea and sugarbeet yields was positive while cotton yield decreased with increasing precipitation during the growing season. The results of chi-square analysis for wheat yield demonstrated that the critical time in which extreme temperature led to yield loss differed among regions. In Bojnourd, in late April to early May, and excess days (high or low yield years have more days meeting a cardinal value than normal years) with maximum temperature higher than 30 degrees C, wheat yield decreased while in Birjand, cooler maximum temperature (
  • Authors:
    • O'Donovan, J.
    • Harker, K.
    • Clayton, G.
    • Brandt, R.
    • Hao, X.
    • Blackshaw, R.
    • Johnson, E.
    • Vera, C.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 1
  • Year: 2011
  • Summary: Nitrogen fertilizer is a major input cost in canola ( Brassica napus L.) production and farmers are interested in improving N use efficiencies. A multi-site study in western Canada was conducted to determine the merits of polymer-coated urea (Environmentally Smart Nitrogen, ESN) compared with urea on weed management and yield of hybrid and open-pollinated (OP) canola. Treatments included a hybrid and OP canola cultivar, ESN and urea, 100 and 150% of soil test N fertilizer rates, and 50 and 100% of registered in-crop herbicide rates. Canola was grown in rotation with barley ( Hordeum vulgare L.) in a no-till system and both crops of the rotation were present each year. Fertilizer and herbicide rate treatments were applied to the same plots in four consecutive years to determine annual and cumulative effects. Hybrid compared with OP canola reduced weed tissue N concentration in 40% of the cases and reduced weed biomass in 80% of the cases. Additionally, weed tissue N concentration was lower with ESN than with urea in 70% of the cases, indicating that crop-weed competition for soil N might be reduced if ESN were used. Canola yield was greater for the hybrid cultivar in 15 of 20 site-years. Both cultivars expressed a positive yield response to the 150% N fertilizer rate in 10 of 20 site-years. This yield response occurred in three additional site-years with hybrid canola, indicating that hybrid cultivars have a higher N demand under favorable growing conditions. Canola yield was similar with ESN and urea in 14 of 20 site-years. The ESN compared with urea increased canola yield in 4 site-years and in one additional site-year for hybrid canola, indicating that ESN may be advantageous in some situations. Canola seed oil concentration was similar with ESN and urea in 19 of 20 site-years. Information gained in this study will be used to develop improved fertilization strategies for canola production on the semiarid Canadian prairies.
  • Authors:
    • José-María, L.
    • Sans, F. X.
  • Source: Weed Research
  • Volume: 51
  • Issue: 6
  • Year: 2011
  • Summary: Weed seedbanks are a reserve of weed diversity and can contribute to the prediction of future weed problems in arable fields. Managing seedbanks should therefore help in optimising biodiversity and controlling weed infestations. This study assessed the effects of management system (organic vs. conventional) and landscape complexity on seedbank size and species richness at the edges and centres of Mediterranean dryland cereal fields and examines the relationship between specific management practices and seedbanks. Field edges and organic fields had more species-rich, denser seedbanks than field centres and conventional fields, and landscape complexity had a limited effect on arable seedbanks. Accordingly, the promotion of low-intensity farming practices regardless of landscape complexity, especially at field edges, would be an effective measure for conservation purposes in Mediterranean agroecosystems. Nevertheless, the high seed density of organic seedbanks reveals the need for more effective seedbank management. The analysis of the effects of specific management practices highlights the importance of cleaning crop seeds properly to reduce seedbank size and using complex rotations, especially as this tends to conserve species richness while reducing seed abundance.
  • Authors:
    • Kugbei, S.
  • Source: Journal of Crop Improvement
  • Volume: 25
  • Issue: 3
  • Year: 2011
  • Summary: Production figures in 2008 showed that new private seed enterprises in Afghanistan produced and sold about 12,000 tons of certified wheat seed, which accounted for 95% of the total certified seed produced in the country. At a retail price of about US$1,200 per ton, the enterprises earned an average margin of 20%. When interviewed, the farmers ranked high yield as by far the most important characteristic they sought in improved varieties. Besides yield, the next important attributes were earliness, disease resistance, grain color, and bread making quality. Estimates of on-farm productivity showed that use of improved wheat varieties alone could contribute up to 33% incremental yield under irrigated conditions, whereas the use of quality seed could enhance yield further by 28%. These estimates were obtained under recommended fertilizer rates, in the absence of which yield levels would have declined substantially. Apart from wheat, other major crops the farmers grew varied by regions but in broad terms included rice, vegetables, maize, potato, cotton, barley, watermelon, and alfalfa.
  • Authors:
    • Stevenson, F. C.
    • Legere, A.
    • Benoit, D. L.
  • Source: Weed Science
  • Volume: 59
  • Issue: 1
  • Year: 2011
  • Summary: A conservation tillage study provided the opportunity to test whether tillage effects on the germinable weed seedbank would be consistent across different crop rotations and to investigate the potential residual effects of herbicide treatments terminated 12 yr earlier. Our objective was to measure the effects of tillage (moldboard plow [MP] vs. chisel plow [CP] vs. no-till [NT]), crop rotation (2-yr barley-red clover followed by 4-yr barley-canola-wheat-soybean rotation, compared to a cereal monoculture), and of a prior weed management factor (three intensity levels of herbicide use) on the density, diversity, and community structure of weed seedbanks. Species richness, evenness (Shannon's E), and diversity (Shannon's H′) of spring seedbanks varied little across treatments and over time. Total seedbank density generally increased as tillage was reduced, with some variations due to weed management in 1993 and crop rotation in 2006. Crop rotations generally had smaller seedbanks with fewer species than the monoculture. In 1993, seedbanks with minimum weed management were twice as dense as those with intensive or moderate weed management (approximately 6,000 vs. 3,000 seed m -2). By 2006, seed density averaged 6,838 seed m -2 across intensive and moderate weed management regardless of tillage, but was nearly twice as large in NT (12,188 seed m -2) compared to MP (4,770 seed m -2) and CP (7,117 seed m -2) with minimum weed management (LSD 0.005=4488). Species with abundant seedbanks responded differently to treatments. Barnyardgrass and green foxtail had larger seedbanks in the monoculture than in the rotation. Common lambsquarters and pigweed species had large seedbanks in tilled treatments in the rotation, whereas yellow foxtail and field pennycress contributed to the large seedbanks observed in NT treatments. The latter two species were also associated with residual effects of weed management treatments (terminated 12 yr earlier) in NT. The differential seedbank response of weed species, attributed in part to contrasting weed emergence patterns and agronomic practice effects on seed rain, explained some of the weak treatment effects observed for total seedbank density and diversity. The large weed seedbanks observed in NT plots after 18 yr confirms the importance of seed rain and seedbank management for the sustainability of NT systems.