Prediction of parental combination for introduction of stay-green associated loci in wheat

In wheat, the increase of yield and stability associated traits can be achieved by combining parents containing the stay-green trait and favorable alleles for grain yield. The aim of this work was to analyze the genetic dissimilarity between wheat lines from stay-green and synchronized maturation groups and elite cultivars. Moreover, to propose promising combinations seeking the selection of high-grain yield and high bread-making quality genotypes containing stay-green trait. The experiment was conducted in a randomized block design with three replications in 2003, 2004, and 2005, using sister-lines with the presence and absence of stay-green trait and elite cultivars. Genetic variability exists among wheat strains from the synchronized stay-green maturation group and elite cultivars. Genotypes of maturation group stay-green obtained an average performance superior to the synchronized group. Crosses between stay-green lines and the CEP 29 and BRS 177 cultivars are promising in the selection of genotypes carrying the stay-green trait with high yield and bread-making quality.     

Development of active polyvinyl alcohol/β-cyclodextrin composites to scavenge undesirable food components

Active food packaging systems based on the incorporation of agents into polymeric package walls are being designed to purposely release or retain compounds to maintain or even increase food quality. The objective of this work was to develop polyvinyl alcohol (PVOH)/β-cyclodextrin (βCD) composite films that can be applied to reduce undesirable component content such as cholesterol in foods through active retention of the compounds in the package walls during storage. Cyclodextrins were added to PVOH in a proportion of 1:1 and cross-linked with glyoxal under acidic media to reduce its water-soluble character. Three different cross-linking procedures were used: cross-linking of the polymer/polysaccharide mixture in solution and film casting, PVOH. βCD*; cross-linking of the polymer, addition of βCD, and casting of the mixture, PVOH*.CD; and casting of a PVOH film, addition of a βCD/glyoxal solution onto the film, and cross-linking during drying, PVOH.CD*. Characterization studies showed that the PVOH*.CD and PVOH.CD* films provided the best physical characteristics with the lowest release values and the highest barrier properties. As a potential application, materials were tested as potential cholesterol-scavenging films. There was a significant reduction in the cholesterol concentration in milk samples when they were exposed to the materials developed.     

Controlled atmosphere storage of wild strawberry fruit (Fragaria vesca L.)

Controlled atmosphere storage technology to extend the shelf life of "Reina de los Valles" wild strawberry fruit (Fragaria vesca L.) was studied. Fruits were stored at 3 degrees C for three weeks in different atmosphere compositions: 0.05% CO2/21% O2 (air), 3% CO2/18% O2, 6% CO2/15% O2, 10% CO2/11% O2, and 15% CO2/6% O2. The effect of gas composition on soluble solids content, titrable acidity, pH, off-flavor, aroma volatiles, and consumer preference was monitored. The result showed that the 10% CO2/11% O2 combination can efficiently prolong the shelf life of wild strawberries by maintaining the quality parameters within acceptable values, through inhibiting the development of Botrytis cinerea, without significantly modifying consumer acceptance.     

Population variability based on the morphometry and chemical composition of the acorn in Holm oak (Quercus ilex subsp. ballota [Desf.] Samp.)

We have studied in this work the natural variability in Holm oak (Quercus ilex subsp. ballota) by analyzing acorn morphometry and chemical composition in 13 populations from the Andalusia region (southern Spain). Acorn morphometry showed statistic significant differences between the populations with a higher acorn weight, length, and diameter in the northern provenances (TJA, GSE, CTH, CHU, APS, and PCO), while the Southern provenances (RMA, SAA, CCO, BCA, and SCA) showed lower value that even decreased with the altitude. Acorn chemical composition also showed statistic significant differences between populations. Morphometry and chemical composition data were subjected to clustering analysis, and two major clusters were detected. This analysis showed that northern populations (CTH, TJA, SCA, CHU, PCO, GSE, and APS) showed a tendency to present values highest in acorn weight (5.42?g vs. 3.21?g); acorn length (37.21?mm vs. 28.73?mm); acorn diameter (16.12?mm vs. 13.79?mm); ash (1.88% vs. 1.55%); protein (4.82% vs. 4.38%); fat (12.55% vs. 9.92%); and oleic acid (66.93 vs. 66.4%). On the contrary, Southern populations (SSA, VJA, CCO, BCA, RG, and RMA) showed a tendency to present values lowest in sugar (10.28% vs. 11.25%); energy (20,076.71?kJ/kg vs. 20,149.26?kJ/kg); palmitic (16.11% vs. 16.39%) and linoleic acids (13.07% vs. 13.11%). The populations studied here seemed to integrate acorn morphology and chemical composition related to environmental conditions of the original provenances. These data have provided biochemical markers that help establish phylogenic associations between populations and also reveal potentially account as an alternative source for dietary nutrition.     

Growth variation among Bacillus thuringiensis strains can affect screening procedures for supernatant‐secreted toxins against insect pests

BACKGROUND: Supernatant‐secreted proteins in Bacillus thuringiensis (Berliner) (Bt) with insecticidal activity provide an important source of information for discovery of new useful strains and/or entomotoxins. However, physiological variation among isolates might interfere in the detection efficiency of screening procedures on Bt collections. The aim of this study was to assess the magnitude of this variation in a sample of isolates from a tropical Bt collection, which was gauged through the assessment of their temporal patterns of growth and protein secretion in culture supernatants (SNs), as well as of the corresponding toxicity against fall armyworm (Spodoptera frugiperda, JE Smith). Feeding bioassays were performed, with larvae being treated with heated and non‐heated total protein extracted from SNs collected at different culture times. Larva mortality and reduction in pupa formation were observed. RESULTS: Intra‐ and interisolate variations were observed in the temporal patterns of growth, quality and quantity of protein secreted, as well as in insecticidal activity of these SNs, based on larvae mortality and pupation rates. These results suggest that the insecticidal potential of certain isolates can be hidden if comparisons are done on the basis of the same number of cells in the culture and/or the same culturing time. CONCLUSIONS: Methods of screening Bt collections on the basis of feeding bioassays can be misleading with regards to identifying more promising isolates for biocontrol purposes if physiological differences are not considered. The consequences and implications of these findings for the development of experimental systems that depend on toxicity bioassays to identify alternative Bt strains and entomotoxins with practical applicability have been discussed. Copyright © 2011 Society of Chemical Industry     

Esterase isoenzymes and insecticide resistance in Frankliniella occidentalis populations from the south-east region of Spain

BACKGROUND: Frankliniella occidentalis (Pergande) is among the most important crop pests in the south‐east region of Spain; its increasing resistance to insecticides constitutes a serious problem, and understanding the mechanisms involved is therefore of great interest. To this end, F. occidentalis populations, collected from the field at different locations in south‐east Spain, were studied in terms of total esterase activity and esterase isoenzyme pattern. RESULTS: Individual thrips extracts were analysed by native polyacrylamide gel electrophoresis (PAGE) and stained for esterase activity with the model substrate α‐naphthyl acetate. Significant correlations were found between resistance to the insecticides acrinathrin and methiocarb and the presence of a group of three intensely stained bands, named Triplet A. For each individual thrips extract, total esterase activity towards the substrates α‐naphthyl acetate and α‐naphthyl butyrate was also measured in a microplate reader. Insects possessing Triplet A showed a significantly higher α‐naphthyl acetate specific activity and α‐naphthyl acetate/α‐naphthyl butyrate activity ratio. This observation allowed a reliable classification of susceptible or resistant insects either by PAGE analysis or by total esterase activity determination. CONCLUSION: The PAGE and microplate assays described can be used as a monitoring technique for detecting acrinathrin‐ and methiocarb‐resistant individuals among F. occidentalis field populations. Copyright © 2008 Society of Chemical Industry