in order to investigating theeffects of  crop rotation and applying of herbicides on weed distribution in  irrigated wheat fields of kermanshah province, this study was performed during  2011-2012. multivariate analysis (rda) revealed the significant relationship between composition and species frequency and exerted management techniques. the first and second features of rda indicated 57%, 74.9...

No-till cropping is an option for growers needing to reduce soil erosion in the Palouse annual-cropped region of the Pacific Northwest, which is well suited for wheat production. A 6-yr field study was conducted to determine optimum levels of fertilizer and herbicide inputs in a no-till continuous wheat crop production system. Three levels of nitrogen (N) and two weed management levels (WML) we...

It is important to develop best management practices for novel tall fescue systems in the southern Great Plains of North America, especially since cool-season perennials are not well known or commonly utilized in this region. This review paper summarizes the research activities in this region of the southern Great Plains for developing new perennial tall fescue systems (establishment, legume-gr...

The level and pattern of nucleotide variation in duplicate gene provide important information on the evolutionary history of polyploids and divergent process between homoeologous loci within lineages. Kengyilia is a group of allohexaploid species with the StYP genomic constitutions in the wheat tribe. To investigate the evolutionary dynamics of the Pgk1 gene in Kengyilia and its diploid relativ...

Integrating use of seeded perennial cool-season grass pastures with native rangeland can increase available forage and provide a high plane of nutrition for grazing livestock. Our objective was to compare performance of yearling beef heifers grazing native rangeland with those grazing an integrated system that included seeded forages. Twice-replicated, 3-ha pastures seeded to either ‘Rosana’ we...

Tall fescue [Lolium arundinaceum (Schreb.)] is a cool-season perennial grass used in pastures throughout the Southeastern United States. The grass can harbor a shoot-specific fungal endophyte (Epichloë coenophiala) thought to provide the plant with enhanced resistance to biotic and abiotic stresses. Because alkaloids produced by the common variety of the endophyte cause severe animal health iss...

Synchronized waving of grass blades in the presence of fluid flow has been observed in cases such as wheat field in wind, marine grass in tidal currents. The synchronous motion can have important environmental and ecological impact via mixing of fluid due to waving. We use a twodimensional analog of these phenomenon in a gravity driven soap film tunnel. Nylon filaments attached to the boundarie...