Progress in breeding perennial grains

2010 ◽  
Vol 61 (7) ◽  
pp. 513 ◽  
Author(s):  
T. S. Cox ◽  
D. L. Van Tassel ◽  
C. M. Cox ◽  
L. R. DeHaan

Annual cereal, legume and oilseed crops remain staples of the global food supply. Because most annual crops have less extensive, shorter-lived root systems than do perennial species, with a correspondingly lower capacity to manage nutrients and water, annual cropping systems tend to suffer higher levels of soil erosion and generate greater water contamination than do perennial systems. In an effort to reduce soil degradation and water contamination simultaneously – something that neither no-till nor organic cropping alone can accomplish – researchers in the United States, Australia and other countries have begun breeding perennial counterparts of annual grain and legume crops. Initial cycles of hybridization, propagation and selection in wheat, wheatgrasses, sorghum, sunflower and Illinois bundleflower have produced perennial progenies with phenotypes intermediate between wild and cultivated species, along with improved grain production. Further breeding cycles will be required to develop agronomically adapted perennial crops with high grain yields.

Plant Disease ◽  
2014 ◽  
Vol 98 (3) ◽  
pp. 389-394 ◽  
Author(s):  
W. F. Schillinger ◽  
T. C. Paulitz

The soilborne fungus Rhizoctonia solani AG-8 is a major concern for farmers who practice no-till in the inland Pacific Northwest of the United States. Bare patches caused by Rhizoctonia spp. first appeared in 1999 during year 3 of a 15-year no-till cropping systems experiment near Ritzville, WA (269 mm of annual precipitation). The extent and pattern of patches were mapped each year from 1999 to 2012 at the 8-ha study site with a backpack-mounted global positioning system equipped with mapping software. Bare patches appeared in winter and spring wheat (SW; Triticum aestivum), spring barley (SB; Hordeum vulgare), yellow mustard (Brassica hirta), and safflower (Carthamus tinctorius). At its peak in years 5 to 7, bare patches occupied as much as 18% of total plot area in continuous annual monoculture SW. The area of bare patches began to decline in year 8 and reached near zero levels by year 11. No measurable patches were present in years 12 to 15. Patch area was significantly greater in continuous SW compared with SW grown in a 2-year rotation with SB. Additionally, the 15-year average grain yield for SW in rotation with SB was significantly greater than for continuous SW. Russian thistle (Salsola tragus), a troublesome broadleaf weed with a fast-growing tap root, was the only plant that grew within patches. This article reports the first direct evidence of natural suppression of Rhizoctonia bare patch with long-term no-till in North America. This suppression also developed in a rotation that contained broadleaf crops (yellow mustard and safflower) in all but 5 years of the study, and the suppression was maintained when safflower was added back to the rotation.


Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 547-555 ◽  
Author(s):  
Richard W. Smiley ◽  
Stephen Machado ◽  
Jennifer A. Gourlie ◽  
Larry C. Pritchett ◽  
Guiping Yan ◽  
...  

There is interest in converting the 2-year rotation of rainfed winter wheat with cultivated fallow in the Pacific Northwest of the United States into direct-seed (no-till) systems that include chemical fallow, spring cereals, and food-legume and brassica crops. Eight cropping systems in a low-precipitation region (<330 mm) were compared over 9 years to determine effects of changes on diseases. Fusarium crown rot was more prevalent in wheat following cultivated than chemical fallow, and Rhizoctonia root rot was more severe when winter wheat was rotated with chemical fallow than with no-till winter pea. Take-all occurred even during the driest years and was more severe on annual spring wheat than on annual spring barley. Inoculum density (picograms of DNA per gram of soil) differed (α < 0.05) among cropping systems for Fusarium culmorum, F. pseudograminearum, Gaeumannomyces graminis var. tritici, and Pythium spp. but not for Rhizoctonia solani AG-8. Phoma medicaginis var. pinodella was detected only where winter pea was planted frequently. This is the first report of P. medicaginis as a component of the dryland stem rot complex of pea in north-central Oregon. Results of this investigation will provide guidance for developing crop species with resistance to Fusarium crown rot and black stem of pea.


2019 ◽  
Vol 103 (1) ◽  
pp. 6-8 ◽  
Author(s):  
Terry Roberts

Since its early rudimentary forms, phosphate fertilizer has developed in step with our understanding of successful food production systems. Recognized as essential to life, the responsible use P in agriculture remains key to food security.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 691-700 ◽  
Author(s):  
J. P. Craig ◽  
R. R. Weil

In December, 1987, the states in the Chesapeake Bay region, along with the federal government, signed an agreement which called for a 40% reduction in nitrogen and phosphorus loadings to the Bay by the year 2000. To accomplish this goal, major reductions in nutrient loadings associated with agricultural management practices were deemed necessary. The objective of this study was to determine if reducing fertilizer inputs to the NT system would result in a reduction in nitrogen contamination of groundwater. In this study, groundwater, soil, and percolate samples were collected from two cropping systems. The first system was a conventional no-till (NT) grain production system with a two-year rotation of corn/winter wheat/double crop soybean. The second system, denoted low-input sustainable agriculture (LISA), produced the same crops using a winter legume and relay-cropped soybeans into standing wheat to reduce nitrogen and herbicide inputs. Nitrate-nitrogen concentrations in groundwater were significantly lower under the LISA system. Over 80% of the NT groundwater samples had NO3-N concentrations greater than 10 mgl-1, compared to only 4% for the LISA cropping system. Significantly lower soil mineral N to a depth of 180 cm was also observed. The NT soil had nearly twice as much mineral N present in the 90-180 cm portion than the LISA cropping system.


Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 712-719 ◽  
Author(s):  
Anne Légère ◽  
Yuguang Bai

The robustness of competitive attributes of cereals such as rapid and uniform seedling emergence, tillering, early biomass accumulation and canopy closure, and height advantage over weeds have not yet been tested under environmental conditions typical of no-till (NT) cropping systems. Our objective was to evaluate the effects or NT practices on growth and productivity ofAvena sativa, Triticum aestivum, Hordeum vulgare, and associated weeds. The experiment was conducted on a Kamouraska clay at La Pocatière, QC, in 1994, 1995, and 1996.Avena sativa, T. aestivum, andH. vulgarewere grown under tilled and NT practices. Cereal growth parameters were measured six (1994) or seven (1995) times between planting and the 11th week after planting but only once in 1996. Grain yields and yield components were determined at crop maturity.Avena sativaandH. vulgarepopulations were little affected by tillage, whereasT. aestivumpopulations were reduced by 16 to 20% in NT systems. Growth in height in NT systems was either similar or greater than in tilled systems in all three cereals. Cereal leaf area index (LAI) and biomass accumulation was also comparable between tillage systems, except forT. aestivumLAI in 1994, which was greater in tilled plots on two sampling dates. Response of annual dicots to tillage was inconsistent in all crops. Annual monocots dominated in some but not all NT systems. Perennial dicots dominated in NT systems, whereas perennial monocots were more abundant in tilled systems in all three cereals.Avena sativaandT. aestivumyields in NT plots were comparable or greater than in tilled plots, in spite of having either lower test weights (A. sativa) or lower 1,000-grain weights (T. aestivum). NTT. aestivumproductivity was maintained in spite of reduced plant establishment.Hordeum vulgareyields were also similar across tillage systems, except in 1995, when yields in tilled plots were greater than in NT plots. The height advantage observed for NTH. vulgaredid not result in improved yields. All three cereals, and particularlyA. sativa, appeared well suited to NT systems, despite the pressure provided by different weed groups, compared to tilled systems. However, results suggest that NT production of cereals could benefit from improved attention to perennial dicot control and crop seedling establishment, particularly forT. aestivum.


2021 ◽  
pp. 1-16
Author(s):  
Rebecca Tapscott

The notion that states pursue a monopoly over the use of force rings increasingly hollow. From vigilantes that patrol the United States’ southern border, to thugs for hire in China, states are characterized by non-state violent actors. These trends are more pronounced in comparatively lower-capacity states. Employing the concept of “security assemblages,” I propose that it is crucial to consider historically embedded relations among violent actors and institutions in order to understand their socio-political role and implications for state authority. This approach offers three insights: first, in low-capacity states, violence is not zero-sum. Rather, it is assembled among diverse actors, which each have historically embedded comparative advantages. Second, therefore, state efforts to monopolize violence should be taken as an empirical question rather than an assumption grounding analysis. Third, relationships between violent actors occur in thick institutional environments, meaning that violent actors, including state actors and institutions, often must act under significant constraints. To illustrate these points, I conduct a mixed-methods nested study of vigilantes in Uganda, finding that vigilantes are more common where other authorities are present, and are more helpful when other authorities are also more helpful. Focusing on dynamics between vigilantes and police, I pinpoint their historically distinct roles: the police were established as a colonial-era institution to suppress political dissent, while vigilantes have long been socially embedded actors tasked with everyday security provision. Thus, in this case, police and vigilantes are not substitutes; instead they play distinct and complementary roles.


1977 ◽  
Vol 69 (4) ◽  
pp. 635-638 ◽  
Author(s):  
L. R. Nelson ◽  
R. N. Gallaher ◽  
M. R. Holmes ◽  
R. R. Bruce

2005 ◽  
Vol 137 (4) ◽  
pp. 497-500 ◽  
Author(s):  
Tuilo B. Macedo ◽  
Paula A. Macedo ◽  
Robert K.D. Peterson ◽  
David K. Weaver ◽  
Wendell L. Morrill

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is an insect pest in dryland wheat cropping systems in the southern Canadian Prairies and the northern Great Plains of the United States (Morrill 1997). Yield losses caused by C. cinctus are due to reduced head weight (Holmes 1977; Morrill et al. 1992) and lodging, which decreases harvest efficiency. Estimates of yield losses in Montana alone are about US$25 million per year.


2015 ◽  
Vol 21 (5) ◽  
pp. 747-758 ◽  
Author(s):  
Hannah H. E. van Zanten ◽  
Herman Mollenhorst ◽  
Cindy W. Klootwijk ◽  
Corina E. van Middelaar ◽  
Imke J. M. de Boer

1991 ◽  
Vol 5 (3) ◽  
pp. 545-552 ◽  
Author(s):  
Charles L. Mohler

Sweet corn was grown with a living mulch of white clover, a dead mulch of rye, and without mulch, in both till and no-till conditions. Unplanted controls were also included in the experimental design. Corn yields were highest in clover treatments early in the experiment but lowest in later years. The declining yields in the clover living mulch were related to the strip application of glyphosate which allowed establishment of perennial and biennial weeds, notably dandelion and horseweed. These overwintering weeds apparently prevented effective control of summer annuals, especially redroot pigweed, common lambsquarters and large crabgrass, by atrazine and metolachlor. Presence of a rye mulch decreased weed biomass and had no detrimental effect on corn yield. In general, corn yield was not affected by tillage, although the number of marketable ears was reduced in the no-till treatments during the drought year of 1988. The much greater weed biomass in the unplanted control treatments showed the importance of crop competition for weed control in sweet corn cropping systems.


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