Field resistance to late blight -a fungal disease caused by Phytophthora infestans -has been genetically characterized by analyzing trait-marker association in a Solanum phureja (phu)×dihaploid Solanum tuberosum (dih-tbr) population. Trait data were developed at three locations over a 3-year period under natural infection pressure. RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism) markers were used to develop anonymous genetic linkage groups subsequently anchored to potato chromosomes using mapped RFLP (restriction fragment length polymorphism), SSR (single sequence repeats) and AFLP markers. RFLP and SSR markers achieved the most-accurate anchoring. Two genetic maps were obtained, with 987.4 cM for phu and 773.7 cM for dih-tbr. Trait-marker association was revealed by single-marker and interval mapping analyses. Two important QTLs (quantitative trait loci) were detected on chromosomes VII and XII as a contribution from both parents, totalling up to 16% and 43%, respectively, of the phenotypic variation (PH). One additional QTL was detected on chromosome XI (up to 11% of the PH) as a contribution from the phu parent, and three others were detected on chromosome III (up to 13% of the PH), chromosome V (up to 11% of the PH) and chromosome VIII (up to 11% of the PH) as a contribution from the dih-tbr parent. Our results reveal new genetic loci of the potato genome that contribute to resistance to late blight. We postulate that some of these loci could be related to plant growth under short-day conditions.

Chile is considered to be a sub-center of origin for the cultivated potato, with native and introduced genetic material coexisting in the country. Thus, the different varieties present in Chiloe Island are characterized by a rich diversity of forms, sizes, colours and phenological characteristics. In the present work, the level of polymorphism and the genetic relationship were studied by means of molecular markers using the amplified fragment length polymorphism (AFLP) technique and twenty-seven morphological characters. Twenty varieties of potatoes from the Chiloe Island were analyzed. The commercial variety Desirée and one specie from the Etuberosa series, Solanum fernandezianum, collected in the Juan Fernandez Island were included as controls. A similarity tree-diagram was made, based on all the AFLP bands generated in the range between 65 and 290 base pairs. With these tools, it was possible to identify molecular differences and similarities that might be associated with important morphological traits such as the predominant forms of the tuber, flower colour and resistance to disease.

RESUMEN El raps canola (Brassica napus L.) representa una alternativa para diversificar la producción adaptándose a las condiciones de suelo y clima de la zona centro sur del país. Se estableció un ensayo para evaluar el comportamiento de cinco genotipos de raps de primavera en dos tipos de suelos de la región de La Araucanía (Andisol y Ultisol). El modelo experimental correspondió a un factorial 5x2 que consistió en cinco genotipos y dos tipos de suelo. Las variables a evaluar en el estudio fueron rendimiento del grano y contenido de aceite de la semilla. Los resultados mostraron efectos significativos de la interacción genotipo x ambiente (suelo) para estos parámetros. El mayor rendimiento en el Ultisol correspondió a los genotipos 'Ability' y 'Sonja', mientras en el Andisol, correspondió a los genotipos 'Gladiador', 'Salsa' y 'Hyola 618'. El mayor porcentaje de aceite en el grano correspondió a los genotipos 'Ability' y 'Sonja', en el Ultisol; y a 'Gladiador', 'Salsa' y 'Hyola 618', en el Andisol. Los resultados del análisis combinado de varianza para el rendimiento por planta de los cinco genotipos de raps y los dos ambientes (tipos de suelo) confirmaron la existencia de efecto de interacción genotipo x suelo.