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La yuca (Manihot esculenta) es el cuarto cultivo en importancia a nivel mundial como fuente de calorías para la población humana después del arroz, el azúcar y el maíz, posicionándose por esta razón como un cultivo primordial para la seguridad alimentaria. Su arquitectura ha sido considerada como un factor clave que subyace a la fisiología del rendimiento, relacionando características morfológicas con productividad. En este trabajo se evaluaron diferentes características de arquitectura vegetal en yuca. Los caracteres fueron evaluados en una población F1 compuesta por 133 hermanos completos (familia K) sembrados en dos lugares biogeográficamente diferentes: La Vega (Cundinamarca) y Arauca (Arauca) en Colombia. Las características evaluadas relacionadas con la arquitectura vegetal fueron altura de la planta (AT), número de brotes (NB), longitud entrenudos (LE), número de raíces (NR), peso de raíces (PR), pigmentación del peciolo (PP), área de la hoja (AH) y tipo de hoja (TH). A partir de los datos obtenidos y empleando un mapa genético de alta densidad basado en SNPs (Single Nucleotide Polymorphisms) se llevó a cabo un análisis de QTLs (Quantitative Trait Loci). Se lograron identificar tres QTLs para La Vega asociados con los caracteres altura total, número de brotes y área de la hoja. Para Arauca se detectaron tres QTLs asociados con altura total, longitud de entrenudos y número de brotes. Los QTLs se distribuyeron en cuatro grupos de ligamiento y explicaron entre 18,93 y 41,92 % de la variación genética. Cassava (Manihot esculenta) is the fourth most important crop worldwide as a source of calories for the human population after rice, sugar and corn and therefore it is considered as a staple crop. Cassava's architecture has been considered as a key factor underlying the physiology of yield, relating morphological traits with productivity. In this work different characteristics of plant architecture were evaluated in a cassava F1 population composed by 133 complete siblings (family K) planted in two biogeographically different zones: La Vega (Cundinamarca) and Arauca (Arauca) in Colombia. The characteristics evaluated related to the vegetal architecture were plant height (AT), number of shoots (NB), internodes length (LE), number of roots (NR), root weight (PR), petiole pigmentation (PP), leaf area (AH) and leaf type (TH). From the data obtained and using a SNP- (Single Nucleotide Polymorphism) high-density genetic map a QTLs analysis (Quantitative Trait Loci) was carried out. It was possible to identify three QTLs for La Vega associated with characters plant height, internodes length and leaf area. From the Arauca's dataset, three QTLs were detected associated with plant height, number of shoots and internodes length. The QTLs were distributed into four linkage groups and explained between 18.93 and 41.92 % of genetic variation.

La yuca (Manihot esculenta) es el cuarto cultivo en importancia a nivel mundial como fuente de calorías para la población humana después del arroz, el azúcar y el maíz, posicionándose por esta razón como un cultivo primordial para la seguridad alimentaria. Su arquitectura ha sido considerada como un factor clave que subyace a la fisiología del rendimiento, relacionando características morfológicas con productividad. En este trabajo se evaluaron diferentes características de arquitectura vegetal en yuca. Los caracteres fueron evaluados en una población F1 compuesta por 133 hermanos completos (familia K) sembrados en dos lugares biogeográficamente diferentes: La Vega (Cundinamarca) y Arauca (Arauca) en Colombia. Las características evaluadas relacionadas con la arquitectura vegetal fueron altura de la planta (AT), número de brotes (NB), longitud entrenudos (LE), número de raíces (NR), peso de raíces (PR), pigmentación del peciolo (PP), área de la hoja (AH) y tipo de hoja (TH). A partir de los datos obtenidos y empleando un mapa genético de alta densidad basado en SNPs (Single Nucleotide Polymorphisms) se llevó a cabo un análisis de QTLs (Quantitative Trait Loci). Se lograron identificar tres QTLs para La Vega asociados con los caracteres altura total, número de brotes y área de la hoja. Para Arauca se detectaron tres QTLs asociados con altura total, longitud de entrenudos y número de brotes. Los QTLs se distribuyeron en cuatro grupos de ligamiento y explicaron entre 18,93 y 41,92 % de la variación genética. Cassava (Manihot esculenta) is the fourth most important crop worldwide as a source of calories for the human population after rice, sugar and corn and therefore it is considered as a staple crop. Cassava's architecture has been considered as a key factor underlying the physiology of yield, relating morphological traits with productivity. In this work different characteristics of plant architecture were evaluated in a cassava F1 population composed by 133 complete siblings (family K) planted in two biogeographically different zones: La Vega (Cundinamarca) and Arauca (Arauca) in Colombia. The characteristics evaluated related to the vegetal architecture were plant height (AT), number of shoots (NB), internodes length (LE), number of roots (NR), root weight (PR), petiole pigmentation (PP), leaf area (AH) and leaf type (TH). From the data obtained and using a SNP- (Single Nucleotide Polymorphism) high-density genetic map a QTLs analysis (Quantitative Trait Loci) was carried out. It was possible to identify three QTLs for La Vega associated with characters plant height, internodes length and leaf area. From the Arauca's dataset, three QTLs were detected associated with plant height, number of shoots and internodes length. The QTLs were distributed into four linkage groups and explained between 18.93 and 41.92 % of genetic variation.

Simple morphological traits are used to describe the architecture of a tree: the growth and branching process, the morphological differentiation of the axes and the position of reproductive structures. The main purpose of this contribution is to describe the growth architecture of the Jurassic conifer trees present at the most basal part of the La Matilde Formation in the locality of Monumento Natural Bosques Petrificados, Patagonia, Santa Cruz province, Argentina, and to compare it with that of extant and fossil conifers. This study is based on a large number of in situ petrified trunks, impressions and external molds of leafy branches and female cones in intimate association or organic connection with the trunks. The cones were assigned to Araucaria cf. A. mirabilis (Speg.) Windhausen emend. Calder (Araucariaceae) based on morphological and anatomical characters. The "Araucaria mirabilis" trees had 3 branching categories, corresponding to the typical pattern in extant Araucariaceae, although 4 branching categories cannot be completely discarded. The main, orthotropic stem (TA1) had rhythmic growth and branching, bearing 3-4, probably up to 6-7 plagiotropic branches in pseudowhorls. The lower part of the trees shows no branch-scars; therefore, self-pruning would have been present. Lateral branches (A2) had rhythmic branching: the branchlets (A3) were distributed regularly on the leading branch, with an alternate arrangement, conforming two orthostichies on the same horizontal plane. The female cones were borne terminal at the tip of peduncles, but lateral in position with respect to A2 branches. Reiteration patterns are present: total reiterations (bifurcated trunks and big, orthotropic branches in trunks with normal plagiotropic branches) and partial reiterations (epicormic branching) were observed. The root system consisted of 6 horizontal roots, no tap root was observed. Two architectural patterns or "morphotypes" were recognized at one of the forest levels studied, in keeping with other pieces of evidence (type of wood, foliage, and cones). The "Araucarioid morphotype or morphotype A" includes most of the studied specimens (i.e. "Araucaria mirabilis" trees); showing pseudowhorls of plagiotropic branches. These characters correspond to Massart's model, with certain modifications in the adult trees due to reiteration processes. Morphotype B was observed in bigger trunks with a distinctive costulated surface, which bear only orthotropic branches irregularly arranged, and without reiteration evidences; they could be assigned to Attim's model and possibly represent a different conifer taxon, though subrepresented. Partial and total reiteration patterns are described for the first time for Jurassic, Gondwanic conifers. Moreover, Massart's model can be followed from Upper Palaeozoic Walchiaceae to Mesozoic Araucariaceae. Fil: Falaschi, Paula. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Grosfeld, Javier Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Zamuner, Alba Berta. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Área Paleobotánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Foix, Nicolas. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Comodoro. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Rivera, Stella M.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentina

La région des Grands Lacs illustre la difficulté de définir le phénomène urbain, étant donné la diversité des situations géo-culturelles et la nécessité de ne pas plaquer l’étiquette « ville » sur tout espace à forte densité humaine. La définition « urbaine » proposée en 1993 par C. Coquery-Vidrovitch pour les enclos royaux qui constituaient les capitales de l’ancien Burundi donne lieu à une discussion sur la nature de ces résidences à la fois rustiques et politiques, leur architecture végétale, le caractère agropastoral de leur économie, leur fluctuation démographique et finalement l’existence d’une organisation politique centralisée sans villes dignes de ce nom. La comparaison avec le Buganda au xixe siècle révèle a contrario une urbanisation fondée sur l’essor d’échanges à longue distance, sur le développement d’une population stable et de métiers spécialisés et sur la mise en œuvre d’une architecture ordonnée mettant matériellement en valeur le centre du pouvoir. The Great Lakes region provides a significant example of the difficulties posed by a the definition of urbanization, given the diversity of geographical and cultural situations as well as the need to avoid applying the label « city » to just any area with a high population density. The definition of « urban » proposed by C. Coquery-Vidrovitch in reference to the royal enclosures that were the capitals of ancient Burundi, provides the starting point for a discussion regarding the exact nature of these rustic, political residences, their vegetal architecture, their agro-pastoral economy, their demographic fluctuations and the presence of a centralized political organization in the absence of true cities. A comparison with 19th century Buganda suggests an alternative urbanization process founded on the growth of long distance commerce, on the development of a stable population with specialized occupations and on an ordered architecture giving material preeminence to the center of power.