Estudio de las afinidades genéticas en clones de Manihot esculenta Crantz de importancia económica para Cuba

The genetic affinity were studied between 12 Cassava clones (Manihot esculenta Crantz) after studying the isozymatical systems: Peroxidase, Phenoloxidase and Carbonic Anhidrase. The MAT-GEN program was used for the analyzing results. All the isozymic systems were polymorphous. The dendrogram showed the formation of four groups, according the phylogenetic relations.Key words: cassava, dendrogram, isozymatical systemSe determinaron las afinidades genéticas entre 12 clones de yuca (Manihot esculenta Crantz), a partir del estudio de los sistemas isoenzimáticos: Peroxidasas, Polifenoloxidasas y Anhidrasa Carbónica. Se empleó para el análisis de los resultados el programa MAT-GEN. Todos los sistemas enzimáticos estudiados resultaron polimórficos, con el mayor grado para las isoenzimas Anhidrasa Carbónica. El dendrograma mostró la formación de cuatro grupos de acuerdo con las relaciones filogenéticas entre los clones estudiados.Palabras clave: dendrograma, sistemas isoenzimáticos, yuc

Establishment of a Core Collection of Traditional Cuban Theobroma cacao Plants for Conservation and Utilization Purposes

Presently, Theobroma cacao L. (cacao) in Cuba is mainly cultivated in the eastern region where plantations comprise a mixture of clonal varieties, hybrids, progeny of Trinidad Selected Hybrids, and traditional—also known as ancient—cacao. The ancient genetic resources, probably the plants most closely related to the original introductions, are endangered by their progressive replacement by modern clones. To promote the conservation and utilization of these genetic resources, a representative sample of 537 traditional Cuban cacao plants was used to develop a core collection. Core collections based on 15 simple sequence repeat (SSR) markers were generated using five different sampling algorithms: random sampling, simulated annealing, stepwise clustering with random sampling, the M strategy, and maximum genetic diversity. The five core collections were designed to capture 95 % of the SSR alleles in the complete collection. The genetic, morphological, and geographical diversity of each core collection was compared with that of the entire collection. The entire collection contained 139 alleles, including 104 rare ones, with the 95 % allelic coverage threshold achieved with 133 alleles. The core collection generated by the maximum genetic diversity algorithm had the lowest number of accessions (185), the highest mean genetic distance (0.486), the lowest morphological character redundancy, and the highest diversity as assessed by the mean Shannon-Weaver diversity index (0.757). This core collection can thus serve as the basis of future improvement programs based on local genetic resources

Study of the genetic affinities in Manihot esculenta Crantz clones of economic importance to Cuba

The genetic affinity were studied between 12 Cassava clones (Manihot esculenta Crantz) after studying the isozymatical systems: Peroxidase, Phenoloxidase and Carbonic Anhidrase. The MAT-GEN program was used for the analyzing results. All the isozymic systems were polymorphous. The dendrogram showed the formation of four groups, according the phylogenetic relations. Key words: cassava, dendrogram, isozymatical syste

DIVERSIDAD GENÉTICA DE ESPECIES SILVESTRES DEL GÉNERO Nicotiana I: CARACTERIZACIÓN MEDIANTE MARCADORES BIOQUÍMICOS

La caracterización de especies silvestres del género Nicotiana resulta de gran interés en los programas de mejoramiento genético de la especie Nicotiana tabacum L. ya que pueden ser empleadas como fuente de genes de resistencia a plagas, a la vez que permiten incrementar la variabilidad genética en la única especie comercial del género en el país. El presente trabajo tuvo como objetivo caracterizar la variabilidad genética en 10 especies del banco de germoplasma del género Nicotiana en Cuba, mediante el análisis de nueve sistemas isoenzimáticos y las proteínas totales. Se emplearon los sistemas peroxidasas, polifenoloxidasas, esterasas, anhidrasa carbónica, superóxido dismutasa, diaforasa, fosfatasas ácidas, fosfatasas alcalinas, enzima málica, así como las proteínas totales. Se realizaron las electroforesis en gelesde poliacrilamida (PAGE) en lámina vertical. El grado de polimorfismo total entre las especies para los sistemas estudiados fue de un 92,7%, siendo los sistemas peroxidasas, fosfatasas ácidas y enzima málica los más polimórficos con un 100%. Estos sistemas junto a las fosfatasas alcalinas y las proteínas totales fueron los de mayor importancia en la identificación y caracterización de estas especies por presentar patrones de bandas propios para cada una de ellas. Este resultado constituye el primer estudio isoenzimático en especies silvestres del banco de germoplasma del género Nicotiana en nuestro país, lo que permitió conocer el grado de variabilidad presente en dichas especies

Effect of the landscape on functional and spatial connectivity in Magnolia cubensis (Magnoliaceae) in two mountain massifs of Cuba

Landscape features impact gene flow and the spatial patterns of genetic variation between populations of a species. Because many Magnoliaceae species occur in fragmented and highly disturbed landscapes, the family provide an excellent model for landscape genetic studies. This research focuses on the subspecies and subpopulations of Magnolia cubensis and aims to: (1) compare the genetic diversity between the different subspecies and their subpopulations, (2) search for patterns between the spatial and genetic distance, (3) quantify the functional connectivity and (4) assess the structural connectivity of the landscape. This study employs 21 microsatellite markers to quantify the genetic diversity, complemented with seven landscape characteristics of the Guamuhaya and Sierra Maestra massifs in Cuba. Magnolia cubensis subsp. acunae does not have a well-defined spatial genetic pattern: there is no evidence of isolation by distance or spatial autocorrelation and the little genetic differentiation between the two subpopulations does not reflect the characteristics of the landscape that separates them or the cost values to cross it. Magnolia cubensis subsp. cubensis presents evidence of isolation by distance and the autocorrelation analyses indicate that the approximate scale of the genetic neighborhood is between 35 and 40 km. There is a marked genetic structure with probability values that indicate the existence of three genetic groups. Large genetic differentiation was only found between Gran Piedra and the other subpopulations, which reflects low gene flow. Our results support the recognition of these subspecies at the species level. We define one evolutionary significant unit in Magnolia cubensis subsp. acunae and two evolutionary significant units in Magnolia cubensis subsp. cubensis. These results must be combined with ecological, social and distribution data, in order to obtain a more accurate and realistic perspective of the conservation management strategies for these taxa