Effect of tissue culture explant source on sugarcane yield components

Clonal propagation of sugarcane(interspecific hybrids of Saccharum)is conducive to spread of systemicdiseases, such as ratoon stunting disease,caused by Leifsonia xyli subsp. xyli. This important disease iscontrolled by obtaining and plantinghealthy seed-cane. In Louisiana, commercialseed-cane initially produced through tissueculture is available to sugarcane farmersand is being widely planted. Long-termacceptability of this seed-cane productionmethod depends on the production of healthyplants that do not differ significantly inphenotypic and yield characteristics fromthe clones originally selected and releasedas commercial cultivars. To determinewhether tissue culture affects yield or itscomponents, three cultivars, CP 70-321, LCP85-384, and HoCP 85-845, were compared inthree successive crops initially plantedwith stalks from three sources: plantsderived from callus culture of the leafroll above the apical meristem, directregeneration from the apical meristem, andconventional bud propagation. Stalks ofplants derived from both explant sourceswere typical of seed-cane farmers wouldpurchase for planting that had beenpreviously rogued for phenotypic variantsand increased by bud propagation.Differences in yield components amongtissue culture explant sources and budpropagated cane only occurred in CP 70-321.Stalk diameter and stalk weight were lowerand stalk population was higher for plantsderived from leaf roll callus compared tobud propagated cane. Yield components weresimilar for plants derived from an apicalmeristem and bud propagation. Individualplant phenotypic variants resulting fromsomaclonal variation were not observed inany of the cultivars derived from eitherexplant source. In summary, genotype andexplant source affected persistent, uniformphenotypic variation resulting from tissueculture that changed some yield components. However, apical meristem culture wassuitable for production of seed-cane, assugarcane derived by meristem culture ofthree cultivars did not differsignificantly from the original germplasmfor any measured yield trait.     

A management programme for Kwiambana Game Reserve,Sokoto state,Nigeria

This paper describes the physical features, climate, vegetation and animals of the Kwiambana Game Reserve as well as the history and the land use patterns around the Reserve. It also outlines the management problems and makes proposals to solve them. The management programme includes recommendations for game and habitat management, and general administration of the Reserve.     

Adenohypophysial transmembrane potentials: polarity reversal by elevated external potassium ion concentration

Incubation of rat adenohypophyses in potassium ion of sufficient concentration to provoke the release of several of the adenohypophysial trophic hormones produces a reversed, positive transmembrane potential in more than half the cells. This finding is consistent with a process of "stimulus-secretion coupling" in which hypothalamic releasing factors act by selective depolarization of their "target" cells. The positive potentials may be due to a prolonged preferential permeability to calcium ions triggered by an initial depolarization of the cell membrane to a threshold value by increased external potassium ion.     

Individual intake and antiparasitic efficacy of free choice mineral containing fenbendazole for grazing steers

A 95-day study (June 25-September 27, 2001) was conducted using 120 steers (311.9+/-2.4 kg) randomly allocated to two treatments: (1) mineral containing 0.55% fenbendazole (FBZ) and (2) control, no FBZ in the mineral. Animals in the FBZ group were individually identified by an electronic tag that was read each time an animal attended the mineral feeder. The feeder was equipped with load cells that enabled individual mineral intakes to be estimated. The FBZ group was provided with non-medicated mineral during a 14-day adaptation period (July 23-August 5) and an 8-day post-medication period (September 17-24). The intake of FBZ was monitored for 14 days during each of the two treatment periods; August 6-19 and September 3-16, separated by a 14-day non-medicated period, August 20-September 2. Control animals had access to non-medicated mineral for the entire 95-day study period. All steers were grazed on alfalfa-grass pasture for the duration of the study and had free access to flocculated, filtered and chlorinated water via an automatic waterer. Fecal samples were collected from steers three times during the experiment July 23, August 27 and September 27, and analyzed for nematode eggs and Giardia sp. cysts. Seventy-five and 83% of the steers in the FBZ group visited the mineral feeder during the first and second treatment periods, respectively. Individual daily mineral and FBZ intake for the first and second treatment periods was 52.9+/-6.6g per day and 10.1+/-1.2mg/kg BW; 72.3+/-8.4 g per day and 11.8+/-1.4 mg/kg BW, respectively. FBZ animals were separated into three groups during each treatment period based on the recommended dose (RD) of FBZ (5 mg/kg/BW), those that received > the RD, those that received < RD but > 50% RD and those that received < 50% of RD. Nematode egg counts and the number of animals infected with nematodes was reduced (p < 0.05) in all cattle that consumed FBZ as compared to control animals. In contrast to nematode eggs, numbers of Giardia cysts was not reduced (p > 0.05) by FBZ as compared to controls in either treatment period. These results may be a reflection of Giardia re-infection occurring following treatment and highlight the need for variation in treatment regimes specifically targeted at the parasite of interest.     

The effectiveness of old and new strategies for the long‐term control of Pteridium aquilinum,an 8‐year test

There is a need for management strategies to control dominant perennial weeds and restore seminatural communities. We compared the effects of five weed control treatments on dense Pteridium aquilinum relative to an untreated experimental control over an 8‐year period with the aim of restoring acid grassland. The weed control treatments tested were as follows: cutting and bruising, both twice and thrice annually, and herbicide treatment (asulam in year 1 followed by annual spot retreatment of all emergent fronds). Pteridium aquilinum performance and plant species composition were monitored. Data were analysed using Bayesian mixed‐effect models and multivariate techniques. Cutting twice and thrice yearly and the asulam treatment all reduced frond density to zero; both bruising treatments were ineffective. The plant communities in the cut and asulam‐treated plots showed differences from the untreated and bruised plots; the asulam‐treated plots contained more ruderal species and the cut plots were more typical of acid grassland. Acid grassland recovery was fastest in the asulam‐treated plots, but the cut plots caught up after approximately 5 years. There were two important conclusions. First, an intractable weed like P. aquilinum can be eradicated and a vegetation more suited for grazing can be achieved by the continuous application of some treatments over many years. Here, success was achieved by cutting twice/thrice annually, or by a single asulam application followed by annual spot spraying of all emergent fronds for 8 years. Second, bruising, a treatment favoured by some conservation organisations, did not work and cannot be recommended. The use of long‐term, continuously applied treatments might be considered for all perennial weeds with large underground root/rhizome systems.     

Compost Layering Effects on Poultry Litter Leaching: A Column Study

Incorporation of poultry litter (PL) into the nutrient management strategy of crop producers in South-western British Columbia is an important end-use for this agricultural waste product. Environmental and ecological concerns associated with leaching of nutrients by over-winter field storage of PL need to be addressed. To mitigate some of these concerns, some farmers store the manure on a base pad of City of Vancouver yard trimmings compost (YTC), with an additional covering layer of YTC. An outdoor column leaching study was designed to observe the effects of the YTC base pad and covering on the quality of leachate emanating from the PL, as well as to determine the maximum leachability of nutrients from these materials over the storage period. The YTC cover increased (P<0.05) the leaching of nitrogen (N), copper (Cu), and zinc (Zn) from the PL below. The YTC base pad under the PL decreased (P<0.05) the cumulative Cu, Zn and P leached as compared to the PL alone by 50%, 54% and 30%, but had little ability to retain N or soluble salts. Concentrations in the first flush of leachate out of the PL were reduced by the YTC base pad from 25 to 1.3 mg Cu L^?1, 11 to 0.95 mg Zn L^?1, and 430 to 40 mg P L^?1. The high calcium content and cation exchange capacity of the YTC are credited with much of this retention. We recommend that farmers continue to store PL on a base pad of YTC with some improvements, and that the YTC cover is used to isolate the PL from wildlife.     

Prothrombin time and activated partial thromboplastin time using a point‐of‐care analyser (Abaxis VSpro®) in Bennett's wallabies (Macropus rufogriseus)

There are few reports of coagulation times in marsupial species. Blood samples collected from 14 Bennett's wallabies (Macropus rufogriseus) under anaesthesia during routine health assessments were analysed for prothrombin time (PT) and activated partial thromboplastin time (aPTT) using a point‐of‐care analyser (POC) (Abaxis VSPro®). The wallabies had an aPTT mean of 78.09 s and median of 78.1 s. The PT for all wallabies was greater than 35 s, exceeding the longest time measured on the POC. Although PT was significantly longer, aPTT was similar to the manufacturer's domestic canine reference range.     

The identification of a barley haze active protein that influences beer haze stability: Cloning and characterisation of the barley SE protein as a barley trypsin inhibitor of the chloroform/methanol type

Previous pilot brewing trials have demonstrated that in the absence of a molecular weight (MW) 12,000 (barley silica eluate (SE) protein), the beer brewed from the malt of these SE −ve varieties formed less haze after accelerated ageing than beers brewed using SE +ve malt varieties. The previously described SE protein was characterised using comparative two-dimensional (2-D) gel electrophoresis immunoblots of barley seed extracts from both SE +ve and SE −ve varieties. The SE protein spot identified was excised and its partial sequence determined, after in-gel cleavage using trypsin and separation of the resulting fragments by reversed-phase high performance liquid chromatography (HPLC). N-terminal sequence analysis of the tryptic peptides from SE +ve and SE −ve varieties identified the SE protein as the barley trypsin inhibitor-CMe precursor (BTI-CMe). The mature BTI-CMe protein is 13.3 kDa and its functional gene is located on chromosome 3H. Cloning of the BTI-CMe protein demonstrated that both SE −ve and SE +ve barley varieties contain a BTI-CMe protein family member that is similar but has a consistently different sequence, primarily in the last 30 amino acid residues of their C-termini.