In order to increase the efficiency in the production of maize hybrids seeds it is necessary high grain yield with a relative low cost of production. It needs an expansion of the basic knowledge of the heredity of the characters that may be developing new breeding technique. The balanced lethal system (BLS) permit to study the relative contribution of different chromosome segments to hybrid vigour due to the heterocigozity of certain chromosome segments while the rest of the genome go to homocigozity for continuous selfing . In this way, theses segments can be transfer to inbreed lines in order to increase the grain yield and tassel size with pollen production. The objective of this work was to transfer heterotic segments of a line regulated by a balanced lethal system (BLS), through crossing and backcrosses, to an inbred line derivate of a commercial hybrids ACA 2000 of closs pedigree, with the finality of increase the grain yield or pollen production. The variance analysis and principal components showed a significance improvement in the grain yield and tassel size with pollen production in the inbred lines, with the heterotic segment of the BLS line.

The objective of this work is to study the genetic process related to the hybrid vigour (heterosis) and the identification of quantitative trait loci (QTL) in maize. A biometric model was built using the mathematical formalism relating to the discrete absorbent Markov chain in canonical form, in order to analyse the evolution of chromosome segments, with recessive lethal genes linked with grain yield factors through generations. The grain yield obtained from an inbred maize line regulated by a balanced lethal system, and other lines without this system as control, were evaluated during five inbreeding generations. The use of the Markov chain theory for the study of evolution during these generations was a different approach of the classical mathematical ones.

El objetivo de este trabajo es estudiar los procesos genéticos relacionados con el vigor híbrido (heterosis) y la identificación de QTL (Quantitative Trait Locus) en el maíz. Para obtener los resultados, se construyó un modelo biométrico usando los formalismos relacionados a las cadenas absorbentes discretas de Markov en forma canónica, con el fin de analizar la evolución de segmentos cromosómicos, con genes recesivos letales ligados con factores de rendimiento en grano a través de las sucesivas generaciones. El rendimiento en grano obtenido de una línea de maíz regulada por un sistema de letales balanceados y otras líneas sin este sistema como testigo, se evaluó durante 5 generaciones de endocría. El uso de la teoría de las cadenas de Markov con el fin de estudiar la evolución durante estas generaciones fue una aproximación diferente a los métodos matemáticos clásicos.

As moscas Calliphoridae têm a importância sanitária e forense, e níveis diferentes de associação com os ambientes humanos (sinantropia). Conseqüentemente, as variações da diversidade específica em cada área poderiam ser usadas como um indicador do impacto antrópico. Neste estudo, a comunidade de Calliphoridae em Hudson (Argentina) foi coletada em três areas com graus diferentes de Sinantropia (natural, rural e urbana). As moscas foram atraídas com iscas e capturadas com rede entomológica. Doze coletas foram feitas em cada área e os índices de diversidade de Simpson e de Shannon foram calculados. A área natural foi a mais diversa. As outras duas áreas não mostraram nenhuma diferença significativa entre si. A diversidade foi mais elevada no meio da primavera e no fim do verão, e mais baixa no fim de primavera e no começo do verão. As alterações devido aos ambientes humanos afetam a diversidade, diminuindo a abundância de algumas espécies.

Blowflies have sanitary and forensic importance, and different levels of association with human settlements (synanthropy). Therefore, specific diversity changes in each site could be used as an indicator of the anthropic impact. In this study, the community of Calliphoridae in Hudson (Argentina) was sampled in three sites with different degrees of Synanthropy (natural, rural and urban). Flies were attracted with bait and collected with an insect net. Twelve samples were collected in each site and both Simpson and Shannon diversity indexes were calculated. The Natural area was the most diverse. The other two areas showed no significant differences between them. The diversity was higher in the middle of spring and in late summer, and lower at the end of spring and in the beginning of summer. Alterations due to human settlements affect diversity by decreasing the abundance of some species.