No abstract

<p><span style="font-size: medium;">En Colombia, en los últimos 15 años, se ha desarrollado un proceso de investigación para la ampliación de la frontera agrícola focalizado en la altillanura plana, con énfasis en la construcción de capa arable asociado a la saturación de bases, mediante el encalamiento, la labranza vertical y la rotación arroz, maíz y soya, con la posibilidad de otras especies como el algodón que podrían ingresar al modelo. Para ello, se realizó una investigación pionera en Colombia para determinar la adaptación del algodón en las condiciones de las sabanas ácidas mejoradas de la altillanura. Se desarrolló una prueba de evaluación agronómica con cinco genotipos élites de algodón en un diseño de bloques completos al azar en cuatro localidades en suelos con una saturación de bases superior al 80 %. Los resultados permitieron identificar un genotipo (LC-156), que presentó una adaptación a la altillanura, asociado a un rendimiento promedio de 2,2 t/ha de algodón semilla, 1,5 t/ha de algodón tipo fibra media a larga y un porcentaje de extracción de fibra superior al 36,0 %. La ventaja comparativa de esta región para una producción sostenible de algodón está dado por el rendimiento de algodón fibra superior al promedio nacional, reducción del 33,2 % en los costos de producción, calidad de fibra media larga con destino para la exportación y la ausencia del insecto plaga de mayor importancia económica en Colombia, el picudo (Anthonomus grandis Boheman).</span></p>

Jatropha curcas L. is a wild species in the domestication process with an oil and biofuel potential use. The evolutionary-adaptive processes have conferred a reproductive mechanism based on protogyny-geitonogamy, achieving a floral asynchrony addressed to ensure the outcrossing and survival in extreme climate and soil conditions. In the wild, this plant performs a fruit heterogeneity, an unattractive attribute for harvest timing. Therefore, this research aimed to determine the number of harvest, yield and proportion, and physiological states of fruit maturity with the maximum oil quantity and quality. A randomized complete block factorial arrangement of treatments design was performed. The varieties and stages of fruit ripeness, were the factors. A relation of 19: 31: 36: 14 with fruits pericarp colors: green: yellow: yellow-brown: brown, was obtained. The best harvest timing was during the yellow-brown state, which represented the highest oil content associated with high oleic acid and linoleic contents. Nevertheless, for a fruit harvest timing, the use of the epicarp color index is recommended. These results suggest the floral asynchrony breeding traits, requires the ensuring of the fruit homogeneity for mechanical or manual harvesting.

Soybean in Colombia is constituted, like corn, as the main raw material for the production of balanced concentrates for animal feeding. The national soybean production satisfies only 7.0% of the demand for poultry-swine chain, with imports in 2014 of 363501 tons of grain and 1018256 tons of soybean meal. Currently, in Colombia, soybean is only produced in the Orinoquia region, mainly in the high plains and foothills and is part of the rice-corn-soy rotation system for the colonization of native savannas. In order to promote cultivation which allows the occupation of 500000 potentially hectares in the foothills with new varieties beyond current and meet domestic demand, Corpoica is responsible for the plant breeding. As a result of a research in plant genetic resources during nine years (2006-2014), the study of a group of elite soybean genotypes on two contrasting regions: high plains and foothills. In addition, main components analysis per genotype-location interaction were determined for L-189 genotype identified with specific adaptation to the foothills and the highest experimental yield of 2660 k.ha-1, superior in more than half a ton to the yield obtained by the control varieties (P-34 and Superior 6); with traits which bring competitive advantages such as a larger number of pods per plant (56) and smaller seeds (15.2g), besides an acquired tolerance to the Cercospora sp. pathogen.

<p>Con el fin de determinar el número de genes involucrados en el tipo de resistencia de desarrollo lento de la roya de la hoja en las variedades de trigo Pavón 76,Hermosillo 77 y Nacozari 76, se realizó un estudio en el Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT) localizado en Texcoco, Estado de Méjico. Para el efecto, se obtuvieron las cruzas simples posibles de estas tres variedades con una variedad susceptible carente de genes de resistencia, denominada Jupateco 73^S. Los progenitores y 74 familias F₅, de cada una de las seis cruzadas, fueron sembradas en un diseño de bloques completos aI azar con un arreglo de parcelas divididas con tres repeticiones. La respuesta a la enfermedad en las familias F₅, se evaluó calculando el Área Bajo la Curva de Progreso de la Roya de la Hoja (ABCPRH). El estudio genético se realizó mediante el análisis dialélico de Griffing, (1986) (Modelo 2, Método 4), a partir del cual se estimaron las varianzas requeridas para calcular el número de genes involucrados en cada cruza mediante la fórmula de Wright, (1968). La resistencia genética a la roya de la hoja fue controlada por dos genes en las variedades Pavón 76 y Hermosillo 77 y por tres genes en Nacozari 76, sobre la base de que Jupateco 73^S no posee genes efectivos de resistencia.</p><p> </p><p><strong>Number of genes involved in slow-rusting to leaf rust (Puccinia recondita f. sp. tritici) in wheat.</strong></p><p> In order to determine the number of genes involved in the type of leaf rust resistance called "slow rusting" in Pavón76, Hermosillo 77 and Nacozari 76 wheat varieties a study was carried out at the International Maize and Wheat Improvement Center (CIMMYT) located in Texcoco, State of Mexico. All possible single crosses were entered into these three varieties with a susceptible lacking variety genes resistance called Jupateco 73^S.Parents and 74 F₅ families of each cross were planted in a split plot randomized block design with three replications. The disease was evaluated using the Area Under the Leaf Rust Progress Curve (AULRPC). The genetic studies were achieved according to the model 2 Method 4 of Griffing,(1956) aiming the required variances to calculate the number of genes involved in each cross, according to Wright's (1968) formula. The leaf rust genetic resistance was controlled by two genes in Pavón76 and Hermosillo 77 varieties and by three genes in Nacozari 76, based on Jupateco 73^S does not possess effective genes of resistance.</p>