A. Mincione

Pollen markers for gene-centromere mapping in diploid potato.

The utility of two pollen genetic markers for estimating the extent of meiotic recombination between the centromere and a marker gene was tested in 2n pollen of diploid potato clones. One of these markers was the distal locus amylose-free (amf) on chromosome 8 and the other was the isozyme locus alcohol dehydrogenase (Adh-1) on chromosome 4. In the case of the amf locus, the gene-centromere distance was estimated in a normal synaptic and a desynaptic genotype. In both cases the genetic analysis was confined to: (1) a direct estimation of the phenotypic (blue vs red) segregation ratios in FDR (first-division restitution) 2n pollen and (2) a classification of the 4 x progeny from 4x (nulliplex amf) x 2x (Amf/amf) crosses into duplex, simplex and nulliplex classes. The recombination frequency between the centromere and the amf locus in the normal synaptic genotype B92-7015-4 corresponded to a gene-centromere distance of 48.8 cM, whereas this distance amounted to 13.3 cM in the desynaptic genotype RS93-8025-1. Hence desynapsis reduced crossing-over by 73%. The observed genetic distance of 48.8 cM in the normal synaptic clone, B92-7015-4, is the highest gene-centromere distance reported so far in potato and this could be explained on the assumption of absolute chiasma interference. For the Adh-1 locus, it was found that heterozygous 2n pollen grains could be detected in pollen samples of the diploid clones, because of the occurrence of a heterodimeric band of the isozyme. Unlike the amf locus, the genecentromere distance for the Adh-1 locus was estimated only on the basis of the duplex, simplex and nulliplex classes in the progenies from 4x (nulliplex Adh-12)x B92-7015-4 (Adh-11/Adh-12)crosses and was found to be 19.4 cM. Because the accurate positions of centromeres in relation to other loci are not available in the existing genetic maps of potato, which are saturated with molecular markers, halftetrad analysis is a promising additional approach to the basic genetics of this crop.

Supercritical carbon dioxide separation of bergamot essential oil by a countercurrent process

The efficiency of separation of bergamot essential oil, performed by a countercurrent column filled with Raschig rings and using supercritical carbon dioxide as partition solvent, is affected by various parameters. In the experiments explained in this work, the direct effect of CO2 density was shown and the ratio between the amount of oil loaded to on the column and the amount of CO2 used were discussed. The conditions that produced extracts with a similar volatile fraction composition of starting material and with a high yield (more than 80% of recovery) were those with a low feed:solvent ratio; the lowest bergaptene content was obtained at low CO2 density or at high feed:solvent ratio. A good result was observed at a CO2 density of 206 g/dm3 (8 MPa of pressure and a temperature gradient of 46–50–54 °C) and a feed:solvent ratio of 9.4–9.6; in this separation, a yield of 74–77% and a bergaptene content lower than 0.01% was measured. Copyright

Volatile composition and sensory analysis of Italian gianduja torrone

BACKGROUND Gianduja torrone (GT) is a typical Italian product made with almonds, honey and chocolate. In this study, the volatile composition and the descriptive sensory analysis of the product, from five different manufacturing companies and two consecutive seasons (2007 and 2008), were studied. Volatile compounds in torrone samples were extracted using simultaneous distillation-extraction and isolated, quantified and identified using GC-MS. RESULTS Aromatic hydrocarbons were the predominant chemical compounds in the GT samples, mainly being artificial aromas (vanillin and benzaldehyde) added as ingredients. Although pyrazines from chocolate (tetramethylpyrazine, 2,5-dimethylpyrazine, etc.) were found in lower concentrations than the added flavourings, they played an important role in determining the sensory aroma profile of GT, as scores for chocolate flavour were the highest. Although the almond and honey flavours were similar in products from all companies, the chocolate cover and the quantity of vanilla added determined significant differences in the products. CONCLUSION The chocolate cover and artificial aromas play the main role in determining the aroma of GT. If manufacturers are interested in providing a more homogeneous product to the consumers, more attention should be paid to the raw materials chosen (black or milk chocolate) and concentrations of the aromas added.

Construction of an image-based germplasm data base for Phaseolus spp.

SummaryIn this paper a hardware-software computer aided germplasm classification and evaluation system is described. Sample data (Phaseolus spp. seeds) were acquired into the system through a video camera. The resulting digital images were stored into an IPGRI-compliant database structure running in a graphical operating environment.The data base structure was based on a series of forms, with the capability of simultaneous display of image and data fields.Within the forms, an original system based on pop-up menus and icons for fast evaluation and classification of bean accessions was implemented. This gives the operator the possibility to choose among pre-stored standard sample images, the one which matches better the actual accession phenotype.Furthermore, prototype fundamental operating capabilities and possible implementations in the fields of genetics, breeding and germplasm storage and classification are discussed.