The objective of this work was to use a marker-assisted selection for pyramiding the resistance loci Rpv1 and Rpv3.1 in grapevine (Vitis vinifera), and to evaluate their conferred resistance against Brazilian downy mildew (Plasmopara viticola) isolates. A progeny of 23 plants, segregating for the two resistance loci, was obtained by the cross between the Gf 2000-305-122 and Gf.Ga-52-42 genotypes. The progeny was genotyped with four microsatellite markers and phenotyped for resistance to P. viticola using a bioassay with leaf discs. Six plants containing the Rpv1 and Rpv3.1 pyramided loci were identified by the molecular analysis. Plants harboring the Rpv1 + Rpv3.1, Rpv3.1, and Rpv1 loci showed 12.8, 30.0, and 33.1 sporangiophores per leaf disc, respectively. Plants with no resistance loci showed a dense sporulation. The phenotypic analysis of the expression of the two pyramided loci was only confirmed for four plants that showed the highest resistance level, i.e., mean value of 1.8 sporangiophores. A high-throughput method for pyramiding the Rpv1 and Rpv3.1 loci was developed, which confirmed the increased resistance to P. viticola. The selected elite genetic material shows a high resistance to downy mildew and elevated enological potential for grapevine breeding in Brazil.

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 𝐅 𝟏 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.

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.

Phenotypic studies with native fruits are important sources of information for understanding the status of conservation of plant species, especially populations in protected areas (PAs). Fruits of 18 populations of feijoa [Acca sellowiana (O. Berg.) Burret] present in three kind of PAs, Quilombolas Communities (QLs), Indigenous Lands (ILs) and Conservation Units (CUs) were evaluated with the aim to characterize the phenotypic variability. Fruits were harvested at maturity and eight morphological descriptors were measured: diameter, length, total weight, pericarp weight, pulp weight, pericarp thickness, pulp yield and solid soluble contents (°Brix). The results revealed the existence of large morphological variability for all traits, with significant differences among all populations and among those populations grouped in QLs, TIs and UCs, particularly to the total weight and peel thickness. There was a clear formation of five major clusters of genetic dissimilarity. In addition, two Uruguayan type populations and 16 Brazilian type populations showed contrast means for most of the evaluated traits. The lower variability on fruit characters found in plants collected in areas of traditional people but not in CUs suggests the existence of selection processes of feijoa genotypes on those areas.