Identification, introgression, and validation of fruit volatile QTLs from a red-fruited wild tomato species.

Volatile organic compounds (VOCs) are major determinants of fruit flavor, a primary objective in tomato breeding. A recombinant inbred line (RIL) population consisting of 169 lines derived from a cross between Solanum lycopersicum and a red-fruited wild tomato species Solanum pimpinellifolium accession (SP) was characterized for VOCs in three different seasons. Correlation and hierarchical cluster analyses were performed on the 52 VOCs identified, providing a tool for the putative assignation of individual compounds to metabolic pathways. Quantitative trait locus (QTL) analysis, based on a genetic linkage map comprising 297 single nucleotide polymorphisms (SNPs), revealed 102 QTLs (75% not described previously) corresponding to 39 different VOCs. The SP alleles exerted a positive effect on most of the underlying apocarotenoid volatile QTLs-regarded as desirable for liking tomato-indicating that alleles inherited from SP are a valuable resource for flavor breeding. An introgression line (IL) population developed from the same parental genotypes provided 12 ILs carrying a single SP introgression and covering 85 VOC QTLs, which were characterized at three locations. The results showed that almost half of the QTLs previously identified in the RILs maintained their effect in an IL form, reinforcing the value of these QTLs for flavor/aroma breeding in cultivated tomato.

Exploring New Alleles Involved in Tomato Fruit Quality in an Introgression Line Library of Solanum pimpinellifolium.

We have studied a genomic library of introgression lines from the Solanum pimpinellifolium accession TO-937 into the genetic background of the "Moneymaker" cultivar in order to evaluate the accession's breeding potential. Overall, no deleterious phenotypes were observed, and the plants and fruits were phenotypically very similar to those of "Moneymaker," which confirms the feasibility of translating the current results into elite breeding programs. We identified chromosomal regions associated with traits that were both vegetative (plant vigor, trichome density) and fruit-related (morphology, organoleptic quality, color). A trichome-density locus was mapped on chromosome 10 that had not previously been associated with insect resistance, which indicates that the increment of trichomes by itself does not confer resistance. A large number of quantitative trait loci (QTLs) have been identified for fruit weight. Interestingly, fruit weight QTLs on chromosomes 1 and 10 showed a magnitude effect similar to that of QTLs previously defined as important in domestication and diversification. Low variability was observed for fruit-shape-related traits. We were, however, able to identify a QTL for shoulder height, although the effects were quite low, thus demonstrating the suitability of the current population for QTL detection. Regarding organoleptic traits, consistent QTLs were detected for soluble solid content (SSC). Interestingly, QTLs on chromosomes 2 and 9 increased SSC but did not affect fruit weight, making them quite promising for introduction in modern cultivars. Three ILs with introgressions on chromosomes 1, 2, and 10 increased the internal fruit color, making them candidates for increasing the color of modern cultivars. Comparing the QTL detection between this IL population and a recombinant inbred line population from the same cross, we found that QTL stability across generations depended on the trait, as it was very high for fruit weight but low for organoleptic traits. This difference in QTL stability may be due to a predominant additive gene action for QTLs involved in fruit weight, whereas epistatic and genetic background interactions are most likely important for the other traits.

Procedimientos invasivos dirigidos por ultrasonido en el área perinatal:(experiencias de la Unidad de Perinatología del HUC) / Invasive procedure to direct for ultrasonics in perinatal area

Desde el advenimiento del ultrasonido de tiempo real, los diagnósticos que se pueden realizar en el área perinatal son cada vez más precoces y de mejor calidad, permitiendo desarrollar procedimientos invasivos intrauterinos con la finalidas no sólo diagnóstica sino también terapéutica. En la Unidad de Perinatología del Hospital Universitario de Caracas, contamos con la infraestructura tanto física como humana, que nos permite la realización de una serie de procedimientos invasivos dirigidos por ultrasonido, para precisar Dx. VIROLOGICO y CROMOSOMICO en muchos casos y servir en otros en forma terapéutica ante determinadas patologías. El presente trabajo tiene como finalidad no la descripción teórica de los procedimientos, sino la preparación resumida de una serie de casos con determinadas patologías a las que se realizaron procedimientos invasivos con equipos de Ultrasonido de tiempo real, sectorial y lineales (Convex), con Transductores de 3,5 MHz

Sirenomelia: presentación de un caso / Sirenomelia: report of a case

Se reporta un caso de Sirenomelia diagnosticado en la Unidad de Perinatología del H.U.C., cuya evaluación antenatal reportó aligoamnios severo, retardo de crecimiento intrauterino y ausencia de imagen ecográfica renal. El diagnóstico se hizo en la etapa postnatal. Dentro de la clasificación de Forster, el caso en cuestión se trata del tipo Symelia Apus. Presentó además defecto abierto del tubo renal. Es de hacer notar la dificultad diagnóstica que detérmina la presencia de oligoamnios severo en estos casos, lo cual limita la evaluación de la anatomía fetal por ultrasonido. Se brinda una revisión de la literatura sobre etiopatogenia y manejo diagnóstico de los casos de Sirenomelia