Applied research on multiple land use through silvopastoral system in Southern Chile

In 1977 a silvopastoral system was started in a 8.5 há farm with the typical soil characteristics of the coastal ranges of Southern Chile, planted with Radiata pine (Pinus radiata D.Don) 2/0, with a 2.5 × 7 m spacing. The sheep management system began in June 1979.The stocking rate varied from 6 to 8 sheep per há, the ewe breeds were Romney, Suffolk × Romney, with Suffolk or Romney rams. During the 1979–1982 period ratational grazing in four paddocks with native pasture and subterranean was used. Starting from June 1982 pasture area had increased to 12 há.Forage was not conserved. Overnight, sheep were kept loose on a slatted floor sheep house.D.M./há availability, sheep and lamb weight, reproduction and growth of lambs, show that the system is feasible and practical. The 1980 production was 214 kg of live weight/há; 248kg/há in 1981; 171 for 1982, and 207 for 1983. During these years the mean wool production was between 3.5 to 4 kg per sheep.The economic results f the system are attractive as to improve farmers' income, also preventing erosion, allowing a means to promote development of an important area in Southern Chile.The research project is still in progress.     

Parental participation in progeny and effective population sizes in experimental seed orchards of wild cherry Prunus avium L. (Batsch)

Parents and progenies genetic diversity, and male and female contributions to the seed crop were assessed in three experimental Prunus avium seed orchards. Collected data were used to compare different effective population sizes, based on phenological, seed crop and paternity analysis. Our results did not show any difference of genetic diversity between parents and progenies. A limited pollen pollution was detected. We showed that distance and coflowering among clones had a significant effect on effective pollination, and a significant effect of the production of flowers was revealed in one of the seed orchards. Our study also revealed a quite low number of effective size of fathers per mother, but high effective sizes of mothers, fathers and parents at the level of the seed orchard. Finally, the calculation of effective size of mothers, fathers and parents was not highly modified when having the complete information based on the paternity analysis.     

Broodstock spawning and larviculture of whiting (Merlangius merlangus L.) reared in captivity

In recent years, an increasing interest in the farming of marine ‘white’ fish, such as cod, has been observed in the aquaculture industry. One species being considered for aquaculture development is whiting (Merlangius merlangus L.). With little data being available on the domestication of this species, our study aimed to characterize spawning behaviour and rhythmicity in captive broodstock and provide original data on egg incubation, embryonic development and larval rearing. The results observed through video recording showed that spawning mainly occurred at night with active courtship behaviour. Daily egg batches were collected from two separate spawning seasons, with an average fertilization success declining from 77% to 53%. Time to hatch was inversely related to the incubation temperature and occurred after 78 degree‐days (9 days at 8 °C), with emerging larvae ranging in size from 3.3 to 3.46 mm total length and hatch success ranging from 48.3% to 99.9%. In comparison with a clear water environment, a green water regime during the first days of larval rearing significantly improved larval growth and survival. These results are the first to describe spawning activity, early development and larval performances in whiting and are promising for the potential future development of whiting aquaculture.     

Embolism induced by winter drought may be critical for the survival of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. near its southern distribution limit

Introduction   

Scots pine populations in the SE “Sistema Ibérico” range suffered a severe defoliation in the S face of the crown in isolated trees of thinned stands. This process was detected at the end of the winter 2001–2002.     

Breeding maize lines for complete and partial resistance to maize streak virus (MSV)

Summary S₁ to S₅ inbred lines, derived from a maize population bred for its overall resistance to three tropical viruses, were screened for resistance to maize streak virus (MSV) by artificial plant infection using viruliferous leafhoppers. Symptoms were rated and intra-line frequency distributions studied for all pedigree inbred lines. Mortality due to MSV was very low among these inbreds. Symptoms appeared later, developed slower and were less severe than in the susceptible control hybrid. Results of a study of 500 S₁ and 93 S₂ lines suggested that resistance is under genetic control via a system involving loci with major genes (with dominance for resistance) controlling high to complete resistance, associated with a genetic system involving loci with minor genes controlling partial resistance. Lines expressing complete resistance to MSV were developed from 5 cycles of inbreeding and selection. The relevance of such complete and partial resistance is discussed.Abbreviations MRPS Mean Rating for Plants exhibiting Symptoms     

Identification and synthesis of 2-heptanethiol, a new flavor compound found in bell peppers

2-Heptanethiol was identified for the first time as a constituent of red and green bell pepper extracts. The chemical structure of this new aroma compound was proposed on the basis of mass spectra and retention indices and confirmed by chemical synthesis and nuclear magnetic resonance spectroscopy measurements. Its aroma properties were described as sulfury, onion-like, and vegetable-like, reminiscent of bell pepper at lower concentrations, with an orthonasal detection threshold of 10 microg/L of water. No differences in odor note and threshold value were observed for the enantiomeric forms, which were prepared from enantiopure 2-heptanol by tosylation, followed by thioacetylation and reduction, giving the target thiol enantiomers.     

Sucrose, glucose, and fructose extraction in aqueous carrot root extracts prepared at different temperatures by means of direct NMR measurements

Solutions obtained by heating carrot roots in water (stocks) are widely used in the food industry, but little information is available regarding the metabolites (intermediates and products of metabolism) found in the stock. The effect of treatment temperature and duration on the sugar composition of stocks was investigated directly by quantitative (1)H NMR spectroscopy, to understand the extraction mechanism when processing at 100 degrees C. Stocks prepared at three different temperatures (50, 75, and 100 degrees C) were investigated for up to 36 h. Three sugars (sucrose, glucose, and fructose) were detected and quantified. The concentrations of these three sugars reached a maximum after 9 h when the temperature of treatment was 50 or 75 degrees C. At 100 degrees C, the sucrose concentration reached a maximum after 3 h, whereas the concentration of glucose and fructose was still increasing at that time. Comparison of the kinetic composition of these carrot stocks with that of model sugar solutions leads to the proposal that the changes in stock composition result from sugar diffusion, sucrose hydrolysis, and hydroxymethylfurfural (HMF) formation.     

New method for reducing the binding power of sweet white wines

Sulfur dioxide is now considered to be a toxic chemical by most world health authorities. However, it remains an irreplaceable additive in enology for wine conservation, combining antioxidant and antibacterial properties. Sweet white wines from botrytized grapes retain particularly high SO 2 levels due to their high sulfur dioxide binding power. This paper presents a new method for reducing this binding power by removing some of the carbonyl compounds responsible, which are naturally present in these wines. The main carbonyl compounds responsible for the SO 2 binding power of sweet wines were removed, that is, acetaldehyde, pyruvic acid, 2-oxoglutaric acid, and 5-oxofructose. The method retained was selective liquid-solid removal, using phenylsulfonylhydrazine as a scavenging agent. The scavenging function was grafted on different classes of porous polymer supports, and its efficiency was evaluated on sweet white wines under conditions intended to conserve their organoleptic qualities. The results obtained showed that the method was efficient for removing carbonyl compounds and significantly reduced the binding power of the wines. Sensory analysis revealed that this process did not deteriorate their organoleptic qualities.     

Response to domestication and selection for growth in the European sea bass (Dicentrarchus labrax) in separate and mixed tanks

Selective breeding of European sea bass (Dicentrarchus labrax) receives a growing interest, as the estimated heritability of growth is medium to high. In this study, we compared the offspring of four groups of sea bass sires, mated with the same wild dams: wild (W), first generation of domestication (D), first generation of mass selection for length (M), first generation of PROSPER-like selection for length (P). The comparison was done both in replicated tanks (separate rearing) and in mixed tanks (mixed rearing) where sire origins were recovered by genotyping of eight microsatellite markers. Weight, length and growth rate were measured from day 238 post-fertilization (69 g mean weight) to day 611 post-fertilization (390 g mean weight). Both in mixed and separate tanks, both selected groups (P, M) were larger than unselected groups (W, D). No difference was seen at any time between W and D, nor between M and P. The selection response estimate on weight was larger in mixed tanks when compared to separate tanks (+ 42% in mixed tanks, + 23% in separate tanks at day 611), yielding realized heritability estimates of 0.60 and 0.34, respectively, and confirming the excellent potential of the species for growth improvement through selective breeding. Both selection response and the amplification effect between mixed and separate tanks decreased as rearing density increased. Our hypothesis is that selection response is magnified by competition in mixed tanks, while sub-optimal rearing conditions lower the observed selection response, more in separate tanks (where selected thus larger fish are at a higher density than unselected ones) than in mixed tanks (where all fish experience the same density effects).     

Structure of the exon junction core complex with a trapped DEAD-box ATPase bound to RNA

In higher eukaryotes, a multiprotein exon junction complex is deposited on spliced messenger RNAs. The complex is organized around a stable core, which serves as a binding platform for numerous factors that influence messenger RNA function. Here, we present the crystal structure of a tetrameric exon junction core complex containing the DEAD-box adenosine triphosphatase (ATPase) eukaryotic initiation factor 4AIII (eIF4AIII) bound to an ATP analog, MAGOH, Y14, a fragment of MLN51, and a polyuracil mRNA mimic. eIF4AIII interacts with the phosphate-ribose backbone of six consecutive nucleotides and prevents part of the bound RNA from being double stranded. The MAGOH and Y14 subunits lock eIF4AIII in a prehydrolysis state, and activation of the ATPase probably requires only modest conformational changes in eIF4AIII motif I.