Weed competitiveness of the lowland rice varieties of NERICA in the southern Guinea Savanna

Weed competition is a major constraint to lowland rice production in West Africa. Interspecific rice varieties named New Rice for Africa (NERICA) may have superior weed competitiveness and could as such play an important role in integrated weed management. The NERICA varieties were developed from the wide cross between high-yielding Oryza sativa (L.) and weed competitive and disease resilient Oryza glaberrima (Steud.). In this study weed competitiveness of all 60 lowland varieties of NERICA (NERICA-L) was compared with their most frequently used parents [IR64 (O. sativa) and TOG5681 (O. glaberrima)], the weed competitive variety Jaya (O. sativa) and the O. glaberrima upland NERICA parent CG14. During the 2006 and 2007 rainy seasons these varieties were grown under weed-free and weedy conditions in a lowland farmers’ field with partially controlled irrigation in south-east Benin. Weedy plots included single hand weeding at 28 days after sowing, whereas weed-free plots were weekly weeded.     

Fractionation of phosphorus in soils with different geological and soil physicochemical properties in southern Tanzania

ABSTRACT

Soil phosphorus (P) forms have been practically defined as chemically fractionated pools. A knowledge of the abundance and diversity of P forms in soil, and the factors affecting them, will lead to better soil management. However, little is known about the differences in P forms among soils with different geological properties in tropical Africa. The aim of this study was to investigate the P forms in soils with different physicochemical properties formed under different geological conditions in southern Tanzania and to identify the factors affecting the P forms in these soils. In total, 37 surface soil samples were collected from three geological groups; the plutonic (mainly granite) rock (PL) group, the sedimentary and metamorphic rock (SM) group, and the volcanic ash (V) group. Soil P was sequentially extracted by NH₄Cl, NH₄F, NaHCO₃, NaOH + NaCl, and HCl, and inorganic (P_i) and organic P (P_o) in each fraction were determined. The lowest total P was in the PL group (average, 360 mg P kg^-1) because of the high sand content. Iron (Fe)-P (NaOH-P_i) was the major form in this group, accounting for 8.4% of total P. In the SM group (average total P, 860 mg P kg^-1), Fe-P was the major form in most, accounting for 7.8% of total P. Soils in the SM group occasionally had high calcium (Ca)-P due to application of chemical fertilizer at the collection site. The V group had the highest total P (average, 1600 mg P kg^-1) and its major P form was Ca-P, which was possibly derived from primary minerals (i.e., apatite), accounting for 14% of total P. In addition, the high oxalate-extractable Al possibly caused the accumulation of Al-P in the V group. Oxalate-extractable Fe generally increased with increasing Fe-P_i, while oxalate-extractable Al increased with increasing organic P and Al-P_i in soils in all three geological groups. These results demonstrate that the soil P forms differ greatly among sites in southern Tanzania with different geological conditions and associated soil properties.     

Hematological and splenic Doppler ultrasonographic changes in dogs sedated with acepromazine or xylazine

Objective

To evaluate the onset and duration of hematological changes and the use of Doppler ultrasound (spleen) in dogs sedated with acepromazine or xylazine.

Genetic relationships among sympatric varieties of <Emphasis Type="Italic">Acer mono</Emphasis> in the Chichibu Mountains and Central Hokkaido,Japan

Acer mono Maxim. is one of the major components of cool temperate forests in Japan. Some of its many varieties are distributed sympatrically. Because of its great variability, the intraspecific taxonomy and nomenclature of the species are controversial. To understand the genetic relationships among these varieties and whether hybridization or introgression occurred among the sympatric varieties, we studied the genetic relationships among sympatric varieties of A. mono in the Chichibu Mountains (A. mono var. ambiguum, A. mono var. connivens, A. mono var. marmoratum) and Central Hokkaido (A. mono var. mayrii and A. mono var. glabrum) in Japan. Our results showed that varieties in Chichibu are genetically close, suggesting that hybridization or introgression might occur between these varieties, which could explain the higher genetic diversity of varieties in Chichibu than in Hokkaido. In contrast to the close relationships between the varieties in Chichibu, varieties in Hokkaido seemed relatively separated from each other; indeed, there may be reproductive isolation between the two varieties. The results provide new insight for the taxonomy of the varieties of A. mono, especially the sympatric varieties, in Japan.     

Quantitative trait loci analysis for growth and carcass traits in a Meishan x Duroc F2 resource population

We constructed a pig F2 resource population by crossing a Meishan sow and a Duroc boar to locate economically important trait loci. The F2 generation was composed of 865 animals (450 males and 415 females) from four F1 males and 24 F1 females and was genotyped for 180 informative microsatellite markers spanning 2,263.6 cM of the whole pig genome. Results of the genome scan showed evidence for significant quantitative trait loci (<1% genomewise error rate) affecting weight at 30 d and average daily gain on Sus scrofa chromosome (SSC) 6, carcass yield on SSC 7, backfat thickness on SSC 7 and SSC X, vertebra number on SSC 1 and SSC 7, loin muscle area on SSC 1 and SSC 7, moisture on SSC 13, intramuscular fat content on SSC 7, and testicular weight on SSC 3 and SSC X. Moreover, 5% genomewise significant QTL were found for birth weight on SSC 7, average daily gain on SSC 4, carcass length on SSC 6, SSC 7, and SSC X and lightness (L value) on SSC 3. We identified 38 QTL for 28 traits at the 5% genomewise level. Of the 38 QTL, 24 QTL for 17 traits were significant at the 1% genomewise level. Analysis of marker genotypes supported the breed of origin results and provided further evidence that a suggestive QTL for circumference of cannon bone also was segregating within the Meishan parent. We identified genomic regions related with growth and meat quality traits. Fine mapping will be required for their application in introgression programs and gene cloning.     

An outbreak of systemic granulomatous disease in cows with high milk yields

Seven of 92 lactating Holstein cows on a dairy farm developed urticaria with alopecia and decreased milk production, and three of the seven died over the course of 7 to 18 days. Pathologic examination of the three cows, including the two dead and one euthanized cow, revealed that the skin, liver, spleen, kidneys, heart, salivary glands, pancreas, adrenal glands, mammary glands, lymph nodes, and trigeminal ganglia had lymphocytic to lymphogranulomatous inflammation. Inflammation predominated by lymphocytic infiltration was prominent in the heart, pancreas, mammary glands, adrenal gland, and trigeminal ganglia. Severe granulomatous inflammation with multinucleated giant cells was present in the spleen and kidneys. These lesions and their distributions were most similar to those seen in suspected cases of citrus pulp toxicosis and hairy vetch toxicosis. The outbreak of this disease resolved with the elimination of Citrus pulp from the feed. Immunohistochemical detection of lymphocytes and macrophage markers confirmed dramatic hyperplasia of CD3-positive T lymphocytes in these lesions. This strongly suggested that a type 4 hypersensitivity reaction played a role in the development of the lesions.     

The discovery of pyridalyl: a novel insecticidal agent for controlling lepidopterous pests

Synthesis of analogues of two compounds with known insecticidal activity, both of which contain a 3,3-dichloro-2-propenyloxy group, produced 2-(trifluoromethyl)-4-phenoxyphenyl 3,3-dichloro-2-propenyl ether, which had weak activity against lepidopterous larvae. Structural modifications around this lead compound led to the development of pyridalyl [Pleo, S-1812; 2,6-dichloro-4-(3,3-dichloroallyloxy)phenyl 3-[5-(trifluoromethyl)-2-pyridyloxy]propyl ether], which belongs to a new class of insecticides. Pyridalyl gives very good control of various lepidopterous and thysanopterous pests on cotton and vegetables, without phytotoxicity. It controls populations of Heliothis virescens F and Plutella xylostella (L) which are resistant to various currently used insecticides. It also produces unique insecticidal symptoms, so it may have a different mode of action from other existing insecticides. Pyridalyl is also less harmful than existing insecticides to various beneficial arthropods, so it should provide an important tool in IPM and insecticidal management programmes for the control of lepidopterous and thysanopterous pests. The first market introduction is expected in Japan and some Asian countries in the years between 2004 and 2005.     

Chloramphenicol treatment for rabbit syphilis

Penicillin, the recommended treatment for rabbit syphilis, sometimes induces adverse effects. The efficacy of oral chloramphenicol was evaluated in 39 cases of rabbit syphilis to establish a safe and efficient treatment for this disease in companion rabbits. All cases clinically improved and recovered promptly. Fourteen of 39 cases (35.9%) relapsed, but most remained chloramphenicol sensitive. Since safety take priority over efficacy in treating syphilis in companion rabbits, chloramphenicol should be chosen as a first-line agent, as a general rule. Three-week administration of chloramphenicol may be adequate at the initial onset of disease. When relapse occurs repeatedly or the rabbit owner cannot administer the medicine adequately, treatment with penicillin should be considered.     

Variety in histochemical characteristics of the olfactory receptor cells in a flatfish, barfin flounder (Verasper moseri)

Variety in histochemical characteristics of the olfactory receptor cells (ORC) was examined by immunohistochemistry for protein gene product 9.5 (PGP9.5) and calretinin, and by lectin histochemistry with Phaseolus vulgaris leucoagglutinin (PHA-L) in the olfactory epithelium (OE) of the barfin flounder (Verasper moseri). PGP 9.5 immunoreactivity was observed in the ORC situated in the upper three fourths of the OE. Calretinin immunoreactivity was observed in the ORC which seemed to be immunonegative for PGP 9.5. These cells were located in the upper two thirds of the OE. PHA-L staining was observed in small subsets of the ORC. PGP 9.5 and calretinin immunoreactivities and PHA-L staining were also observed in the crypt cells unique to the fish OE. These findings suggest the different properties of olfactory perception among fish ORC.     

Morphogenesis of the olfactory pit in a flatfish, barfin flounder (Verasper moseri)

Morphogenesis of the olfactory pit (OP), olfactory lamella (OL) and olfactory epithelium (OE) was examined by scanning electron and light microscopy in the barfin flounder (Verasper moseri). At day 0 after hatch, the OP was already formed. At day 14, the cellular differentiation of the OE was prominent. At day 42, the OP became a cavity by the formation of its roof. At day 56, the first OL extended remarkably and was lined with the OE on both sides. The OL increased in number with development. These findings suggest that the OE is functionally active at day 14. The formation of the OL in the OP may be initiated by the stimulus when the barfin flounder touched at the bottom of the sea.