Protein Inhibitors ofAlpha-amylase in Mature and Germinating Grain of Rye (Secale cereale)

The activities of endogenous (R-type) and exogenous acting (D-type) protein inhibitors ofalpha-amylase and the activities ofalpha- and total amylase were determined in milling fractions of rye. High D-type amylase inhibitor activities were detected in the embryo (255 IU/g) and in the endosperm fraction (64·9 IU/g), low inhibitor activities were found in the aleurone layer fraction (25·9 IU/g). The highest R-typealpha-amylase inhibitor activity was found in the aleurone layer fraction (32·6 IU/g), and the lowest value in the epidermis containing fraction (5·0 IU/g). The D- and R-typealpha-amylase inhibitor activities varied with growing conditions. D-type amylase inhibitor activities were found to be high in those samples which grew under drought conditions and low in samples cultivated under wet and cool weather. Higher R-typealpha-amylase inhibitor activities were found in rye genotypes cultivated under wet conditions and lower values under dry weather. There were small variations inalpha-amylase inhibitor activities between sprout-stable and sprout-sensitive rye genotypes. The D- and R-typealpha-amylase inhibitor activities of all varieties were stable during 72 h of germination. Similar soil conditions will therefore lead to differentialalpha-amylase inhibitor activities depending on weather conditions during growth.     

Effects of Cover Crops on Soil Quality: Selected Chemical and Biological Parameters

Cover crops improve soil quality properties and thus land productivity. We compared soil chemical and biological changes influenced by hairy vetch (Vicia villosa Roth.) and cereal rye (Secale cereal) cover crops grown in Menfro silt loam (fine-silty, mixed, superactive, mesic Typic Hapludalfs), Mexico silt loam (fine, smectitic, mesic Vertic Epiaqualfs), or sand in the greenhouse. Cover crop biomass, soil β-glucosidase, β-glucosaminidase, and fluorescein diacetate (FDA) hydrolase activities, and soil chemical properties were measured at six, nine, and twelve weeks after planting. Cover crop biomass increased with highest (p < 0.0001) yields for hairy vetch and cereal rye in Menfro and Mexico soils, respectively. β-glucosaminidase, FDA, organic carbon (C), total nitrogen (N), and total phosphorus (P) contents significantly decreased in all soils for both cover crops. However, β-glucosidase activity significantly increased (p < 0.0001). Long-term field studies are needed to evaluate soil quality improvement under cover crops, especially for soils with marginal organic matter and fertility.     

Effects of rye cover crop residue and herbicides on weed control in narrow and wide row soybean planting systems

Α three‐year, non‐irrigated field study was conducted in 1998, 1999, and 2000 at the Southern Weed Science Research Unit farm, Stoneville, MS to study the effects of rye cover crop residue, soybean planting systems, and herbicide application programs on the control, density and biomass of several weed species and soybean yield. The soybean planting systems comprised 19 cm rows with high plant density, 57 cm rows with medium plant density, and 95 cm rows with low plant density. The herbicide programs evaluated were pre‐emergence, postemergence, pre‐emergence followed by postemergence, and no herbicide. Flumetsulam and metolachlor were applied pre‐emergence, and acifluorfen, bentazon, and clethodim were applied postemergence. The presence or absence of rye cover crop residue and a soybean planting system did not affect weed control of the species evaluated (browntop millet, barnyard grass, broadleaf signal grass, pitted morningglory, yellow nutsedge, Palmer amaranth and hyssop spurge), when herbicides were applied, regardless of the application program. In addition, rye cover crop residue was not an effective weed management tool when no herbicide was applied, because density and biomass of most weeds evaluated were higher than a no cover crop residue system. Among soybean planting systems, narrow with high plant density soybeans reduced density of grasses, broadleaf weeds and yellow nutsedge by 24–83% and total weed biomass by 38%, compared to wide with low plant density soybeans. Although weed pressure was reduced by narrow with high plant density soybeans, herbicide applications had the most impact on weed control, weed density and biomass. All herbicide programs controlled all weed species 81–100% at two weeks after postemergence herbicide applications, in comparison to no‐herbicide. Density of grasses and all broadleaf weeds as well as total weed biomass was lower with the pre‐emergence followed by postemergence program than these programs alone. Soybean yields were higher in the pre‐emergence followed by postemergence, and postemergence only programs than the pre‐emergence alone program. Planting crops in narrow rows is one cultural method of reducing weed pressure. However, even with the use of this cultural practice, prevalent weed pressure often requires management with herbicides.     

甘引1号黑麦在高寒地区的适应性评价

通过甘引1号黑麦(Secale cereal cv.Ganyin No.1)在高寒地区适应性栽培试验,以冬牧70(Secale cereale cv.Wintergrazing 70)和固原小黑麦(Triticale Wittmack cv.Guyuan)为对照,对其在高寒地区的生产性能及营养价值做出客观评价。结果表明:甘引1号黑麦较冬牧70和固原小黑麦提前出苗4~6d;在抽穗期前甘引1号黑麦生长速度最快,生长速度2.20cm/d,孕穗期及孕穗期前刈割,一年可收获2茬;甘引1号黑麦的鲜草和干草产量均显著(P0.05)高于冬牧70黑麦和固原小黑麦,干草产量较后两者分别提高53.61%和41.39%,鲜草产量分别提高33.33%和27.45%;甘引1号黑麦粗蛋白、粗脂肪、钙、磷产量分别较固原小黑麦高42.36%、39.0%、54.02%和47.82%,较冬牧70高54.66%、53.61%、61.55%、60.59%。