Abstract Disease resistance gene pyramiding is a widely used strategy to enhance resistance durability. Marker-assisted selection (MAS) was applied to pyramide the alleles Run1 and Ren3, which confer resistance against grape powdery mildew (Erysiphe necator). Two F1 full-sibs carrying Run1 and Ren3 in heterozygosity were selfed to develop the breeding populations used in the analysis. From the 637 genotyped plants, 313 (50.6%) had the Run1 and Ren3 pyramided. Seven (1.1%) of them exhibited the two resistance alleles in homozygosity. Plants without any resistance alleles had the highest disease severity ( = 7.3), while the ones with the Run1 allele both in homozygosity and heterozygosity were highly resistant ( = 1.5). Similar level of resistance was observed in the plants containing Run1 and Ren3 pyramided ( = 1.3). Plants containing Run1 and Ren3 pyramided in homozygosity are important genetic resources for grape breeding programs in Brazil.

Abstract Downy mildew (Plasmopara viticola) is the main grapevine disease in humid regions. In the present investigation, marker-assisted selection (MAS) was used to develop grapevine lines homozygous in loci Rpv1 and Rpv3 for resistance against P. viticola. The experimental populations UFSC-2013-1 (n = 420) and UFSC-2013-2 (n = 237) were obtained by self-pollination of two �� �� full-sib plants, originated from a cross between two distinct breeding lines containing the downy mildew resistance loci Rpv1 and Rpv3 in heterozygosity. The two experimental populations were genotyped with four microsatellite markers flanking the two downy mildew resistance loci. Among 637 genotyped plants, 300 (48.2%) were homozygous for at least one resistance locus and 10 (1.57%) were homozygous for both Rpv1 and Rpv3 alleles. These 10 plants challenged with P. viticola inoculum showed a clearly enhanced level of resistance. These plants have a great potential as resistance donors in grapevine breeding.

The aim of this study was to determine the effect of seeding density on sanitary and agronomic characteristics of promising peanut genotypes, in Quevedo, Ecuador. The following promising peanut lines were used: CB-02, CB-16 and CB-23, Runner type, with a standard distance of 0,50 m between rows and 3,6; 5 and 10 plants m-1 for each cultivar. The disease intensity of leaf spot and rust were determined, furthermore, agronomic variables such as plant height, number of pods and seeds, pod weight per plant, weight of 1000 seeds, weight of pods per parcel and pod yield (kg ha-1). The experiment was carried on a Completely Randomized Block design with 9 treatments and four replications, using a factorial arrangement 3 (lines) x 3 (plants m-1). Tukey’s test at 5% of significance level was used for separation of means. The smallest number of leaf spot and rust lesions was observed on the peanut line CB-23. On the one hand, at plant densities of 3,6 and 5 plants m-1 lead to the highest number of pods per plant (321,83 and 286,50 respectively). On the other hand, the highest plant height (47,24 cm), weight of pods per parcel (2,00 kg) and pod yield (1809,42 kg ha-1) were observed at 10 plants m-1. The interaction between factors was significant for the following variables: number of seeds per plant (p<0,05) and yield (p<0,01), showing the dependence between the analyzed factors

El objetivo del estudio fue determinar el efecto de la densidad de siembra en las características fitosanitarias y agronómicas de genotipos promisorios de maní, en Quevedo, Ecuador. Se utilizaron las líneas promisorias de maní CB-02, CB-16 y CB-23, tipo Runner, con distanciamiento estándar de 0,50 m entre hileras y una población de 3,6; 5 y 10 plantas m-1 para cada cultivar. Se cuantificó la intensidad de cercosporiosis y roya, así también las variables agronómicas altura de la planta, número de frutos y de semillas, peso de frutos por planta de 1000 semillas, frutos por parcela, y rendimiento de frutos (kg ha-1). Fue empleado un Diseño de Bloques Completos al Azar con nueve tratamientos y cuatro réplicas, con arreglo factorial 3 (líneas) x 3 (plantas m-1). Para la comparación entre las medias de los tratamientos se empleó la prueba de Tukey al 5 % de probabilidad del error. La línea de maní CB-23 obtuvo menor número de lesiones para cercosporiosis y roya. Con 3,6 y 5 plantas m-1 fue obtenido el mayor número de frutos por planta (321,83 y 286,50, respectivamente), y con 10 plantas m-1, la mayor altura de planta (47,24 cm), peso de frutos por parcela (2,00 kg) y rendimiento de frutos (1809,42 kg ha-1). Se observó interacciones entre los factores, solamente para el número de frutos por planta (p<0,05) y para el rendimiento (p<0,01), mostrando dependencias entre ellos

Cocoa (Theobroma cacao L.) is one of the main crops of economic importance in Ecuador since small and medium farmers on the coast rely on this income. However, fungal diseases decreases yield. In this research 10 experimental cocoa clones of National type and two commercial control varieties (EET-103 and CCN-51) were evaluated from 2008 to 2011, at plantations located in Quevedo and Tenguel. The objective of this research was to identify disease tolerant clones to frosty pod rot (Moniliophthora roreri) and witches' broom (Moniliophthora perniciosa), while maintaining high production levels. Experimental design was a randomized complete blocks in a factorial arrangement with four replications. Variables measured were number of branches showing witches' broom per tree; percentage of diseased pods; number of healthy pods; total number of pods; and yield of dried cacao almonds (kg ha-1). Commercial clone CCN-51 exhibited the lowest incidence of diseases and the highest production of healthy pods and average almond yield (1047.7 kg ha-1). Four experimental clones showed desirable traits: L46-H57 had the highest number of healthy pods and total pod number; L21-H43, L46-H57 and L46-H88 yielded more than 550 kg ha-1 of almonds; L18-H58 presented fewer number of witches' broom (7.3), and L21-H43 had the lowest incidence of diseased pods (37.0 %). These clones might be used for breeding programs and genetic conservation. The Quevedo location showed higher incidence of fungal diseases and yield of dry cocoa beans than Tenguel.

El cacao (Theobroma cacao L.) es uno de los principales cultivos de importancia económica en el Ecuador, principalmente para los pequeños y medianos agricultores del litoral. Sin embargo, las enfermedades fungosas reducen el rendimiento de este cultivo. Durante los años 2008 a 2011 se evaluó en las localidades Quevedo y Tenguel, el comportamiento de 10 clones experimentales de cacao tipo Nacional con el objetivo de seleccionar los de mayor productividad y tolerancia a dos enfermedades: moniliasis (Moniliophthora roreri) y escoba de bruja (Moniliophthora perniciosa), en comparación con dos testigos comerciales (EET-103 y CCN-51). El diseño experimental fue de bloques completos al azar con arreglos factorial, con cuatro repeticiones. Se registró el número de escobas de bruja vegetativas, porcentaje de mazorcas enfermas, número de mazorcas sanas y totales, así como el rendimiento de almendras secas de cacao. El clon comercial CCN-51 presentó la menor incidencia de enfermedades, así como la mayor producción de mazorcas sanas y rendimiento promedio de almendras (1047.7 kg ha-1). Cuatro clones experimentales presentaron características deseables: L46-H57 con una mayor producción de mazorcas sanas y totales, L21-H43, L46-H57 y L46-H88 con un rendimiento de almendras superior a 550 kg ha-1, L18-H58 con el menor número de escoba de bruja (7.3), y L21-H43 con la menor incidencia de mazorcas enfermas (37.0 %). Estos clones pueden ser utilizados en programas de mejoramiento y conservación. La incidencia de enfermedades fúngicas y el rendimiento de almendras secas de cacao fueron mayores en Quevedo que en Tenguel.