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Crop wild relatives’ genetic diversity is usually not considered in conservation planning. Here, the authors introduce an approach to identify conservation areas based on evolutionary and threat processes, by developing proxies of genetic differentiation, and including taxa’s habitat preferences.

This study assessed the morphological and nutritional diversity induced through gamma irradiation in Lehmann’s love grass. Seed were irradiated at doses of 0, 100, 200, 300, 450, 600, 900, and 1400 Gy. Ten agronomic traits related with forage quality were evaluated and used to select the mutants, which were confirmed by cluster analysis and multivariate analysis of variance and then characterized by nutritional and molecular characterization. Mutants with 16–20% less (p

Las especies comerciales de café presentan diferencias a nivel ploidia, incompatibilidad y autogamia lo que reduce su uso para el mejoramiento genético convencional. El presente trabajo tuvo como objetivo estudiar la radiosensibilidad con rayos gamma de 60Co en café, variedad Oro Azteca, información indispensable para ser considerada en programas de mejoramiento genético por mutagénesis. Se utilizaron semillas de café var. Oro Azteca, las cuales se irradiaron con rayos gamma de 60Co a dosis de 0, 10, 50, 100, 200 y 300 Gy. Las semillas irradiadas se establecieron en un almacigo para su germinación, las plantas M1 se pusieron en macetas de 2 Kg de sustrato y posteriormente se llevaron a un lugar definitivo, distribuyendo los tratamientos en un diseño experimental de bloques completos al azar con cuatro repeticiones. Se evaluaron 15 variables de las cuales dos fueron de semilla, ocho de planta y cinco de fruto. Se calculo la DL50 para porcentaje de germinación y sobrevivencia de plantas mediante regresión exponencial y cuadrática. La GR50 se calculó para altura de planta y número de ramas mediante un modelo de regresión cuadrática II. En las demás variables se evaluó el efecto de las diferentes dosis de radiación. La DL50 para germinación fue de 60.4 Gy y de sobrevivencia de 177.8 Gy. La GR50 para altura de planta fue de 120.1 Gy y para número de ramas de 107.6 Gy. Para la mayoría de las variables la radiación gamma de 60Co disminuyo significativamente sus valores a partir de los 100 Gy.

Objective: In this work, we undertook the task of isolating and identifying Fusarium obtained from papaya fruits grown in the Veracruz region and carried out antibiotic tests to find a beneficial fungus that could exert biological control. Methodology: Juvenile fruits with necrosis and rot were collected from papaya plants of the Maradol variety, from here the pathogenic fungi were obtained, which were morphologically and molecularly characterized using the ITS gene. Subsequently, the isolated pathogenic fungi were confronted with the Trichoderma sp. fungus. Results: Ten isolates were obtained, of which four were Fusarium solani. From the confrontations, a 66% to 100% percentage of inhibition in these pathogenic fungi was obtained. Limitations of the study: It is proposed that future evaluations carry out long-term follow-ups to evaluate the persistence and effectiveness of biological control. Findings/conclusions: Timely identification of pathogens could represent a biological control strategy in disease management programs. [ABSTRACT FROM AUTHOR]

Cacao trees have been cultivated in Mesoamerica for at least 4,000 years. In this study, we analyzed sequence variation in the chloroplast DNA trnH-psbA intergenic spacer from 28 cacao trees from different farms in the Soconusco region in southern Mexico. Genetic relationships were established by two analysis approaches based on geographic origin (five populations) and genetic origin (based on a previous study). We identified six polymorphic sites, including five insertion/deletion (indels) types and one transversion. The overall nucleotide diversity was low for both approaches (geographic = 0.0032 and genetic = 0.0038). Conversely, we obtained moderate to high haplotype diversity (0.66 and 0.80) with 10 and 12 haplotypes, respectively. The common haplotype (H1) for both networks included cacao trees from all geographic locations (geographic approach) and four genetic groups (genetic approach). This common haplotype (ancient) derived a set of intermediate haplotypes and singletons interconnected by one or two mutational steps, which suggested directional selection and event purification from the expansion of narrow populations. Cacao trees from Soconusco region were grouped into one cluster without any evidence of subclustering based on AMOVA (FST = 0) and SAMOVA (FST = 0.04393) results. One population (Mazatán) showed a high haplotype frequency; thus, this population could be considered an important reservoir of genetic material. The indels located in the trnH-psbA intergenic spacer of cacao trees could be useful as markers for the development of DNA barcoding.

Induced mutagenesis through gamma radiation generates structural and chemical changes in plants. This study evaluated the morphological and nutritional variability of natal grass [Melinis repens (Willd.) Zizka] plants produced from seed irradiated with gamma radiation. Natal grass seed was collected from wild populations in the state of Chihuahua, Mexico. The seed was exposed to a source of Co60. The radiation doses were: 0, 10, 50, 100, 150, 200, 250, 300 and 350 Gray (Gy). Sixty-six first generation mutant genotypes (M1), produced from irradiated seed, and nine non-mutant genotypes (M0), developed from non-irradiated seed (0 Gy), were evaluated. For the morphological characterization, 18 variables were measured on the plants when they were at the reproductive stage. The nutritional analysis was performed on the M0, as well as on a group of plants from the M1, which resulted morphologically different (p