ABSTRACT The aim of this study was to verify the response of the melon accessions MR1 and C14 to gamma radiation in terms of germination and morphology.The melon accessions came from the germplasm collection of the Federal Rural University of the Semi-arid Region, and were submitted to five doses of gamma radiation (0, 100, 200, 300, 400 Gy) in four replications, each comprising 25 seeds, at the Center for Nuclear Energy in Agriculture of the University of São Paulo. The seeds were grown in a greenhouse at UFERSA employing a completely randomised design. The germination potential, rate and index were evaluated during the first stage of the trial. During the second stage, the germinated plants were transplanted into eight-litre buckets containing substrate and sand, in four replications of 15 plants each. The inflorescence, leaf blade and fruit were evaluated. The IMAGE J image analysis software was used to obtain the leaf and fruit data. The germination potential varied for the gamma-ray doses being tested, while the germination rate and index were not affected; phenotypic variations were seen in the leaves. The gamma-ray doses had no effect on the germination process. MR C C1 morphologyThe morphology Semiarid Semi arid Region 0, 0 (0 100 200 300 40 Gy 2 Paulo design trial eightlitre eight litre sand 1 inflorescence data gammaray ray tested affected leaves process ( 10 20 30 4 3

ABSTRACT The characterisation and evaluation of accessions are important steps in both the management of a germplasm collection and in a plant genetic improvement program. Carrying out characterisation and evaluation, whether morphological or molecular, requires observing the overall features of plants in the field, or collecting leaves for DNA extraction, which is time consuming and costly; whereas DNA extracted directly from the seeds allows access to the genome without the need for planting the seeds, which speeds up the selection of genotypes of interest and information on genetic variability. The aim was to develop a non-destructive method for extracting DNA from cashew seeds. The seeds were mechanically perforated using a mini-grinder, and a sample of the endosperm was removed. Various protocols and commercial kits for DNA extraction were tested, as well as materials to seal the opening made in the seed. It is possible to extract cashew tree DNA from the endosperm, preferably using commercial kits with cementitious adhesive as the sealing material, offering a germination percentage of 60% of the perforated seeds. program molecular field costly variability nondestructive non destructive minigrinder, minigrinder mini grinder, grinder mini-grinder removed tested seed material 60 6

RESUMO As pimenteiras ornamentais apresentam variabilidade genética que pode ser acessada por meio de caracteres morfológicos e moleculares. A seleção de genótipos para formação de população base para o melhoramento pode ser realizada por meio de análise conjunta de vários tipos de dados, proporcionando maior precisão na seleção. Nessa perspectiva, este estudo teve como objetivo avaliar a diversidade entre acessos de pimenta com base na análise de características fenotípicas e marcadores moleculares e selecionar os melhores para serem utilizados como parentais em programas de melhoramento. O trabalho foi realizado no Centro de Ciências Agrárias da Universidade Federal da Paraíba, Paraíba, Brasil. Foram utilizados 16 genótipos de pimenteiras ornamentais, e caracterizados quanto a oito caracteres quantitativos, nove qualitativos e 18 pares de iniciadores microssatélites. As análises simultâneas das variáveis foram realizadas usando o método de agrupamento de Tocher, agrupamento do algoritmo de Ward e a matriz de dissimilaridades. Os métodos de agrupamentos foram eficientes na separação dos genótipos, identificando variabilidade genética e precisão na seleção por meio da análise conjunta de dados quantitativos, qualitativos e moleculares. Diferentes grupos foram formados entre os genótipos pelo método de Tocher (seis grupos) e pelo método de Ward (três grupos). Existe variabilidade genética entre os genótipos de pimenteiras ornamentais, considerando análise conjunta de dados quantitativos, qualitativos e moleculares. Características qualitativas são importantes na identificação de divergência genética entre acessos de pimenteira ornamental. Os genótipos UFPB 46, 134, 137, 443 e 449, o mini pimentão Akamu e a cultivar Calypso são indicados para seleção, podem ser utilizados para realizar cruzamentos e dar continuidade ao programa de melhoramento genético. perspectiva Paraíba Brasil 1 quantitativos microssatélites dissimilaridades seis três grupos. . ornamental 46 134 137 44 449 genético 4 13

ABSTRACT Ornamental pepper plants have genetic variability, which can be accessed through morphological and molecular traits. Genotype selection to form the base population for breeding can be performed through the joint analysis of several types of data, providing greater selection accuracy. From this perspective, this study aimed to evaluate the diversity among pepper accessions based on analysis of phenotypic traits and molecular markers and to select the best ones to use as parents in breeding programs. The study was carried out at the Centro de Ciências Agrárias of the Universidade Federal da Paraíba, Paraíba, Brazil. Sixteen ornamental pepper genotypes were used and characterized for eight quantitative traits, nine qualitative traits, and 18 pairs of microsatellite primers. Simultaneous variable analyses were performed using Tocher’s clustering method, Ward’s clustering algorithm, and the dissimilarity matrix. The clustering methods were efficient in separating the genotypes, identifying genetic variability, and accuracy in the selection through the joint analysis of quantitative, qualitative, and molecular data. Different groups were formed among the genotypes by Tocher’s method (six groups) and Ward’s method (three groups). There is genetic variability among ornamental pepper genotypes considering the joint analysis of quantitative, qualitative, and molecular data. Qualitative traits are important in the identification of genetic divergence among ornamental pepper accessions. The UFPB genotypes 46, 134, 137, 443 and 449, the mini pepper Akamu, and the cultivar Calypso are indicated for selection and can be used to carry out crosses and continue the breeding program. data perspective programs Paraíba Brazil 1 primers Tochers Tocher s Wards Ward algorithm matrix six three groups. . 46 134 137 44 449 Akamu program 4 13

RESUMO: Os estudos visando o melhoramento de lúpulo (Humulus lupulus) no Brasil são recentes e buscam estabelecer a autossuficiência da produção. O conhecimento da variabilidade dos genótipos disponíveis no país é de fundamental importância para o desenvolvimento de um programa de melhoramento de lúpulo. O objetivo do trabalho foi identificar genitores de lúpulo com potencial agronômico e cervejeiro para o Planalto Catarinense, Brasil. Foi utilizado o delineamento em blocos casualizados em esquema fatorial 3x4 com 12 tratamentos: Fator 1: três anos de cultivo (2019, 2020 e 2021) e combinado com o fator 2: quatro genótipos (Cascade, Chinook, Columbus e Hallertau). Os caracteres avaliados foram a massa fresca de plantas (MFP, g), massa verde de cones (MTV, g), a massa seca de cones (MSC, g), os teores de alfa-ácidos (ALFA, %) e a produção (PROD, g per planta). O genótipo Hallertauer demonstrou melhor desempenho e comportamento diferenciado para os caracteres de massa fresca de plantas, massa seca de cones e produção, quando comparado aos demais. Assim, a partir destes resultados observou-se que, existe variação disponível ao melhoramento genético do lúpulo para esses caracteres, fator que permitirá obter ganhos produtivos no desenvolvimento de novas cultivares, a partir deste genótipo promissor. RESUMO Humulus lupulus Catarinense x 3x 1 tratamentos 2019, 2019 (2019 202 2021 2 Cascade, Cascade (Cascade Chinook Hallertau. Hallertau . Hallertau) MFP, MFP (MFP g, , g) MTV, MTV (MTV MSC, MSC (MSC alfaácidos alfa ácidos ALFA, ALFA (ALFA % PROD, PROD (PROD planta. planta planta) demais Assim observouse observou se cultivares promissor 201 (201 20 (20 (2 (

ABSTRACT: Studies on the improvement of hops (Humulus lupulus) in Brazil are recent and seek to establish self-sufficiency in production. Knowledge of the variability of genotypes available in the country is of fundamental importance for the development of a hop improvement program. The objective of the research was to characterize and identify hop parents with agronomic and brewing potential for the Planalto Catarinense region, Brazil. The randomized block design arranged in a 3x4 factorial scheme was used with 12 treatments: (Factor 1: three years of cultivation (2019, 2020 and 2021) and combined with factor: four genotypes (Cascade, Chinook, Columbus and Hallertau). The characters evaluated were fresh mass of plants (MFP, g), green mass of cones (MTV, g), dry mass of cones (MSC, g), alpha-acid content (ALFA, %) and production (PROD, g per plant). The Hallertauer genotype showed better performance and differentiated behavior for the characters of fresh mass of plants, dry mass of cones and production, when compared to the others. Thus, from these results it was observed that there is variation available for the genetic improvement of hops for these characters, a factor that will allow obtaining productive gains in the development of new cultivars, based on this promising genotype. ABSTRACT Humulus lupulus selfsufficiency self sufficiency program region x 3x 1 treatments Factor 2019, 2019 (2019 202 2021 Cascade, Cascade (Cascade Chinook Hallertau. Hallertau . Hallertau) MFP, MFP (MFP g, , g) MTV, MTV (MTV MSC, MSC (MSC alphaacid alpha acid ALFA, ALFA (ALFA % PROD, PROD (PROD plant. plant plant) others Thus cultivars 201 (201 20 (20 2 (2 (

Abstract Introduction. Chickpea has been considered a restricted host species for nodulation, although recent studies describe a greater bacterial diversity associated with the crop to increase the knowledge about this symbiosis in orden to obtain efficient isolates in its contribution. Objective. To characterize and identify an isolate obtained from chickpea plant nodules and evaluate its effectiveness under field conditions. Materials and methods. The research was conducted in the laboratories of two centers: the Institute of Fundamental Research in Tropical Agriculture “Alejandro de Humboldt,” Cuba, and the National Center for Genetic Resources, Mexico, as well as under field conditions in two campaigns during the years 2018 and 2020 to demonstrate its effectiveness in crop interaction in the first center. The isolate R3 was taxonomically identified through the sequencing of four genes. For laboratory experiments, a completely randomized design was used, while plant trials were conducted under a randomized block design. The results were subjected to analysis of variance, and means were compared using the Tukey test (p<0.05). Results. The isolate R3 showed variability in terms of its morpho-physiological and biochemical characteristics. Furthermore, it exhibited significant differences compared to the other treatments in the growth and yield indicators evaluated in chickpea. Conclusions. Rhizobium pusense associated with chickpea nodules was identified for the first time in Cuba. The strain demonstrates growth at pH levels between 5.5 and 9.0 and temperature ranges from 29 °C to 38 °C, indicating its tolerance to these factors. Its inoculation in chickpea stimulates nodule formation and increased yield-related variables.

Resumen Introducción. El garbanzo se consideró durante muchos años una especie de hospedero restringido para la nodulación, aunque estudios recientes describen una mayor diversidad bacteriana asociada al cultivo que permita incrementar los conocimientos acerca de esta simbiosis para obtener aislados eficientes en su contribución. Objetivo. Caracterizar e identificar un aislado obtenido a partir de nódulos de plantas de garbanzo y evaluar su efectividad en condiciones de campo. Materiales y métodos. La investigación se desarrolló en los laboratorios de dos centros: Instituto de Investigaciones Fundamentales en Agricultura Tropical “Alejandro de Humboldt”, Cuba y en el Centro Nacional de Recursos Genéticos, México, así como en condiciones campo en dos campañas durante los años 2018 y 2020, para demostrar su efectividad en la interacción del cultivo en el primer centro. El aislado R3 se identificó a nivel taxonómico mediante la secuenciación de cuatro genes. Para los experimentos en condiciones de laboratorio se utilizó un diseño completamente aleatorizado, mientras que los ensayos con plantas se realizaron bajo un diseño de bloques al azar. Los resultados fueron sometidos a un análisis de varianza y las medias se compararon según el test de Tukey (p < 0,05). Resultados. El aislado R3 mostró variabilidad en cuanto a sus características morfo-fisiológico y bioquímicas. Además, tuvo respuesta con diferencias significativas con respecto al resto de los tratamientos en los indicadores de crecimiento y rendimiento evaluados en el garbanzo. Conclusión. Se identificó por primera vez en Cuba Rhizobium pusense asociado a nódulos de garbanzo. La cepa mostró un crecimiento positivo a pH entre 5,5 y 9,0 y rangos de temperatura desde 29 ºC hasta 38 ºC, lo que evidencia su tolerancia a estos factores. Su inoculación en garbanzo estimuló la formación de nódulos e incrementó variables del rendimiento.

Abstract Introduction. Tomato (Solanum lycopersicum L.) is considered one of the most important crops in the world. Genetic improvement of tomatoes has employed different methods to generate variability, and mutation the induction of mutations is one of the techniques used to obtaining improved varieties. The first step in using this tool is studying radiosensitivity to determine the irradiation dose to be used. Objective. To determine the radiosensitivity and the dose of cobalt-60 gamma rays to be used in three tomato varieties. Materials and methods. This research was conducted in January 2020 at the Instituto Nacional de Ciencias Agrícolas of Cuba. Seeds of three tomato varieties were irradiated with cobalt-60 gamma rays, with doses ranging from 100 Gy to 900 Gy, at intervals of 100 Gy; an unirradiated control was also used. The percentage of germination, plant height, and seedling survival were evaluated. Results. It was observed that higher irradiation dose reduced germination, survival, and plant height. The IDIAP T-7 and IDIAP T-9 varieties reduced germination at a dose of 400 Gy, while the DINA RPs cultivar reduced germination at 300 Gy. Genotypes showed survival values below 50 % at a dose of 800 Gy. Height reduction began at doses of 200 Gy for IDIAP T-7, 300 Gy for DINA RPs, and 400 Gy for IDIAP T-9. Conclusion. The DL-50 doses were identified as 692, 588, and 630 Gy, and the GR-50 doses were 407, 467, and 380 Gy for the IDIAP T-7, IDIAP T-9, and DINA RPs varieties, respectively. The GR-50 dose of each variety was selected for the mutation breeding program.

Resumen Introducción. El tomate (Solanum lycopersicum L.) es considerado uno de los cultivos más importantes en el mundo. La mejora genética del tomate ha empleado diferentes métodos para generar variabilidad, la inducción de mutaciones es una de las técnicas empleadas en la obtención de variedades mejoradas. El primer paso, en el uso de esta herramienta, es el estudio de radiosensibilidad para determinar la dosis de irradiación a emplear. Objetivo. Determinar la radiosensibilidad y la dosis de rayos gamma de cobalto-60 a emplear en tres variedades de tomate. Materiales y métodos. Esta investigación se desarrolló en enero del año 2020, en el Instituto Nacional de Ciencias Agrícolas de Cuba. Se irradiaron con rayos gamma de Cobalto-60 semillas de tres variedades de tomate, con dosis entre 100 Gy y 900 Gy, con intervalos de dosis de 100 Gy; también se empleó un control sin irradiar. Se evaluaron el porcentaje de germinación, la altura y la sobrevivencia de las plántulas. Resultados. Se observó que a mayores dosis de irradiación se redujo la germinación, la sobrevivencia y la altura de las plántulas. Las variedades IDIAP T-7 e IDIAP T-9 redujeron su germinación a la dosis de 400 Gy y el cultivar DINA RPs a los 300 Gy. Los genotipos presentaron valores de sobrevivencia por debajo del 50 % a la dosis de 800 Gy. La reducción de altura inició a la dosis de 200 Gy para la variedad IDIAP T-7, 300 Gy para DINA RPs y 400 Gy para IDIAP T-9. Conclusión. Las dosis de DL-50 identificadas fueron 692, 588 y 630 Gy y las dosis deGR-50 fueron 407, 467 y 380 Gy para las variedades IDIAP T-7, IDIAP T-9 Y DINA RPs, respectivamente. Se seleccionó la dosis GR-50 de cada una de las variedades para el programa de mejora por mutaciones.

ABSTRACT. A study determining microsatellite markers was conducted to compare similarities among three different populations of Macrobrachium tenellum prawns from three different hydrological basins in Oaxaca, Mexico. In total, nine different markers in the population were used, of which six coded for the three populations and three did not. Although different, the three populations are closely genetically related, with an average allele richness from 6.845 to 16.754 and a heterozygosity of 0.166 to 0.264. However, the relationship could be much closer, particularly between them. The possible applications and scope of this knowledge are commented on and discussed.

Abstract: Lipoprotein (a) (Lp(a)) is a particle similar to low-density lipoprotein (LDL) linked to an Apolipoprotein (a). This gives it atherogenic and prothrombotic properties that make it an independent risk factor, not only for atherosclerotic disease but also for other pathologies such as severe aortic stenosis. Given its high genetic determination and low variability due to environmental factors, it is recommended to measure levels of Lp(a) at least once in a lifetime. We present the case of a patient with an estimated low cardiovascular risk based on traditional risk factors, who developed severe coronary artery disease in the context of elevated Lp(a) levels.

Resumen: La Lipoproteína (a) (Lp(a)) es una partícula similar a la lipoproteína de baja densidad (LDL) pero unida a una Apolipoproteína (a). Ello le confiere propiedades aterogénicas y protrombóticas que la transforman en un factor de riesgo independiente, no solo de enfermedad aterosclerótica sino de otras patologías como la estenosis aórtica severa. Dada su alta determinación genética y menor variabilidad frente a factores ambientales, se recomienda la medición de sus niveles al menos una vez en la vida. Presentamos el caso de una paciente catalogada de bajo riesgo cardiovascular basado en factores de riesgo tradicionales pero que desarrolló enfermedad coronaria severa en el contexto de niveles de Lp(a) elevados.

SUMMARY: Owing to extensive overexploitation and continuous habitat loss in recent decades, Dalbergia stevensonii has become endangered in Central America and its place of origin. Genetic diversity is essential for ensuring the long-term survival of the species and is vital in breeding programs. However, knowledge of the genetic diversity of D. stevensonii is limited, as no study has been conducted to estimate the population variability in Guatemala. This study is the first to determine the genetic diversity and structure of wild populations of D. stevensonii in Guatemala using molecular markers. The genetic diversity of 90 wild D. stevensonii trees from six populations located in their natural range is currently being evaluated. Genetic diversity was moderate, with an average of 5.83 alleles per locus, a mean Shannon index value of 1.42, and observed and expected heterozygosity of 0.32 and 0.37, respectively. AMOVA indicated that only 6 % of the genetic variation was between populations, and genetic distance values (pairwise FST) suggested moderate differentiation between populations. STRUCTURE and DAPC analyses revealed the existence of three clusters for the 90 samples, while the genetic differentiation among populations is attributed more to genetics than to geographic distance. Conservation of the genetic diversity of D. stevensonii is critical to ensure its long-term survival, and the success of breeding programs focused on improving the traits and characteristics of the species, such as growth rate, wood quality, and resistance to pests and diseases. These findings provide a crucial genetic basis for conservation, management, and restoration of this endemic species.

RESUMEN: Debido a la sobreexplotación y continua pérdida de hábitats en las últimas décadas, Dalbergia stevensonii está en peligro de extinción en América Central, su lugar de origen. La diversidad genética es un factor esencial para garantizar la supervivencia de la especie a largo plazo y es vital en los programas de mejoramiento. Sin embargo, el conocimiento sobre la diversidad genética de D. stevensonii es limitado, ya que no se ha realizado ningún estudio para estimar la variabilidad de las poblaciones en Guatemala. Este es el primer estudio realizado en Guatemala para determinar la diversidad genética y la estructura de las poblaciones silvestres de D. stevensonii utilizando marcadores moleculares. Actualmente, se está evaluando la diversidad genética de 90 árboles silvestres de D. stevensonii procedentes de seis poblaciones situadas en su área de distribución natural. La diversidad genética es moderada, con una media de 5,83 alelos por locus, un valor medio del índice de Shannon de 1,42 y una heterocigosidad observada y esperada de 0,32 y 0,37 respectivamente. El análisis AMOVA mostró que solamente el 6 % de la variación genética se presenta entre poblaciones, y los valores de distancia genética (FST por pares) sugieren una diferenciación moderada entre poblaciones. Los análisis STRUCTURE y DAPC revelaron la existencia de tres conglomerados para las 90 muestras, mientras que las diferenciaciones genéticas entre poblaciones se atribuyeron más a la distancia genética que a la geográfica. La conservación de la diversidad genética de D. stevensonii es fundamental para garantizar su supervivencia a largo plazo y el éxito de los programas de mejoramiento centrados en la mejora de los rasgos y características de la especie, como la tasa de crecimiento, la calidad de la madera y la resistencia a plagas y enfermedades. Estos hallazgos proporcionan una base genética crucial para la conservación, gestión y restauración de esta especie endémica.

ABSTRACT: Seventy-five pectinolytic strains collected from vegetables grown in the counties of Santarém, Belterra, and Mojuí dos Campos, located in the western region of the Pará State, Brazil, were studied according to their pathological and genetic variability. The strains were grouped in 5 clusters according to pathogenicity in potato, pepper, carrot, and onion, and 38 strains were selected for genetic analysis using rep-PCR. These strains were divided into 35 genetic groups according to rep-PCR at 70% similarity. These results indicated high pathological and genetic variability of the strains causing soft rot in vegetables in the western region of the Pará State, which will be used in etiological research and for the development and assessment of management techniques for the soft rot in vegetables in this region. ABSTRACT Seventyfive Seventy five Santarém Belterra Campos State Brazil potato pepper carrot onion 3 repPCR. repPCR rep PCR. PCR 70 similarity 7

RESUMO: Setenta e cinco isolados de bactérias pectinolíticas coletados de hortaliças cultivadas nos municípios de Santarém, Belterra e Mojuí dos Campos, região oeste do Estado do Pará, Brasil, foram estudadas de acordo com sua variabilidade patológica e genética. Os isolados foram agrupados em cinco grupos de acordo com a patogenicidade em batata, pimenta, cenoura e cebola, e 38 isolados foram selecionados para análise genética por rep-PCR. Esses isolados foram divididos em 35 grupos genéticos de acordo com rep-PCR a 70% de similaridade. Esses resultados indicaram alta variabilidade patológica e genética dos isolados causadores da podridão mole em hortaliças da região oeste do Pará, os quais serão utilizados em pesquisas etiológicas e para o desenvolvimento e avaliação de técnicas de manejo da podridão mole em hortaliças nesta região. RESUMO Santarém Campos Pará Brasil batata pimenta cebola 3 repPCR. repPCR rep PCR. PCR 70 similaridade 7

ABSTRACT Sugarcane-duck symbiosis (SDS) is an ecological breeding production method wherein meat ducks are released in sugarcane (Saccharum officinarum L.) fields during the middle and late stages of sugarcane growth. The effects of SDS on sugarcane rhizobacterial diversity remain poorly understood. We conducted field experiments with sugarcane monoculture (SC) and SDS and performed genetic analyses on the rhizobacterial communities based on 16S rRNA across different growth stages of sugarcane. The effects of soil physicochemical factors on the bacterial community structure were analyzed via redundancy analysis. We found that soil organic matter (SOM), total N (TN), nitrate N (NN), and ammonium N (AN) contents of sugarcane rhizosphere soils increased during different growth periods in SDS. During the perennial root stages, the Shannon-, Ace-, and Chao1 indices increased, whereas the available P (AP) content decreased. The soil pH was more balanced and its effect on the soil bacterial community was insignificant. The dominant sugarcane rhizosphere flora were Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Firmicutes, norank_f__norank_o__Gaiellales, Sphingomonas, norank_f__Roseiflexaceae, Bacillus, and norank_f__Xanthobacteraceae, but with significant inter-annual variations. Redundancy analysis showed that SOM, TN, NN, AN, AP, catalase (CAT) and invertase (INV) activity were closely associated with the diversity of the soil bacterial communities, and TN and INV activity were the main drivers of sugarcane rhizobacterial communities in the SDS groups. In conclusion, SDS improves the fertilizer supply capacity and soil quality of sugarcane soils by regulating major soil nutrient content, available nutrients, and microbial diversity. This study provides a theoretical basis for scientifically managing SDS and the screening of biocontrol bacteria.

Resumen El pasto banderita [Bouteloua curtipendula (Michx.) Torr.] cuenta con gran variabilidad morfológica y genética en los pastizales del norte de México, lo cual sugiere que existe la posibilidad de selección de genotipos resistentes a condiciones de zonas áridas; sin embargo, la información sobre su eficiencia fotosintética y características estomáticas es escasa. El objetivo del presente estudio fue relacionar la eficiencia fotosintética, características estomáticas y producción forrajera en poblaciones de pasto banderita. Se utilizó un diseño de bloques completos al azar con cuatro repeticiones. Se establecieron 216 macetas en invernadero donde se evaluaron como tratamientos 51 poblaciones de pasto banderita del estado de Chihuahua, México y tres variedades comerciales como testigos. Se evalúo la eficiencia fotosintética y las propiedades estomáticas; además, se cuantificó la acumulación de forraje. Se realizaron análisis estadísticos descriptivos, análisis de correlación, componentes principales, análisis de agrupamiento y análisis multivariado de la varianza. Las medias para disipación de calor no regulada (YNO, 0.223) y disipación de calor regulada (YNPQ, 0.447) indicaron que estas variables son proporcionales a la eficiencia fotoquímica del fotosistema II (YII, 0.330). Los valores máximos y mínimos en producción de forraje fueron 9.8 y 17.92 g por planta y altura de planta de 7.3 y 23 cm, respectivamente. Existe correlación positiva entre área estomática (AE) y disipación de calor regulada con altura de planta y producción de forraje. En el análisis de componentes principales los dos primeros explicaron el 58.8 % de la variación total. Se encontraron 11 poblaciones sobresalientes en disipación de la energía regulada controlando la fotoinhibición, sin poner en riesgo la producción de la planta.

Summary Sideoats grama [Bouteloua curtipendula (Michx.) Torr.] has great morphological and genetic variability present in the grassland of Northern Mexico, suggesting the possibility of selection of genotypes resistant to arid zone conditions; however, information on its photosynthetic efficiency and stomatal characteristics is scarce. The objective of this study swas to relate photosynthetic efficiency, stomatal characteristics and forage production in sideoats grama populations. A randomized complete block design with four replications was used. Two hundred and sixteen pots were established in a greenhouse where 51 populations of sideoats grama from the state of Chihuahua, Mexico were evaluated as treatments along with three commercial varieties as controls. Photosynthetic efficiency and stomatal properties were evaluated, and forage accumulation was quantified. Descriptive statistical analyses, correlation analysis, principal component, cluster and multivariate analysis of variance were performed. Means for unregulated heat dissipation (YNO, 0.223) and regulated heat dissipation (YNPQ, 0.447) indicated that those variables are proportional to the photochemical efficiency of photosystem II (YII, 0.330). The maximum and minimum values in forage production were 9.8 and 17.92 g per plant, and those values for plant height were 7.3 and 23 cm, respectively. Positive correlation exists between stomatal area and regulated heat dissipation with plant height and forage production. In the principal component analysis the first two principal components explained 58.8 % of the total variation. Eleven outstanding populations were found in regulated energy dissipation, controlling photoinhibition without jeopardizing plant production.

Summary Background and aims: In the Atacama Desert certain plant species can be found in small and isolated areas, limited to regions with water availability. The degree of connectivity within and between these natural populations depends on their pollen and seed dispersal abilities, as well as on the barriers imposed by the landscape. Prosopis flexuosa is a species of high economic and ecological importance included in the algarrobo Conservation and Management program. The main objective of this work is to analyze the genetic variability and mating system of P. flexuosa in the Atacama Desert. M&M: Genetic diversity parameters as well as the mating system were evaluated in a natural population (Quillagua) based on microsatellite molecular markers. The hierarchical distribution of genetic variance and kinship coefficients were analyzed. Results: The results indicate high levels of genetic diversity (HE = 0.67-0.65; Ar = 3.83.7), high outcrossing rates (tm = 0.97, ts = 0.85), low biparental inbreeding (11.6%) and multiple paternity. The proportion of full sibs decreases when considering seeds from the same or different pods (89[PRESERVECIRC]16%). Only the variance between families is significant (p < 0.001) and mean kinships estimated show that progenies within families are not only constituted by half sibs. Conclusions: The results are discussed and related to the limited pollen and seed dispersal and their implication for the management of this resource. The study of the mating system parameters of this Chilean desert population suggests that the low population density and the environment fragmentation would not be influencing their mating capacity.

Resumen Introducción y Objetivos: En el desierto de Atacama ciertas plantas viven aisladas y acotadas a regiones con disponibilidad de agua. La conectividad dentro y entre poblaciones depende de las barreras impuestas por el paisaje y de su capacidad de dispersión. Prosopis flexuosa es una especie con alta importancia económica y ecológica incluida en el Programa de Conservación y Manejo del algarrobo. El objetivo de este trabajo es analizar la variabilidad genética y sistema de fecundación de P. flexuosa en el Desierto de Atacama. M&M: Se evaluó la diversidad genética y el sistema de fecundación sobre la base de marcadores moleculares microsatélites en una población natural (Quillagua). Se analizó la distribución jerárquica de la varianza genética y los niveles de las coancestrías. Resultados: Los resultados indican altos niveles de diversidad genética (HE = 0,67-0,65; Ar = 3,8-3,7), fecundación principalmente cruzada (tm = 0,97, ts = 0,85), baja endogamia biparental (11,6%) y paternidad múltiple. La proporción de hermanos completos disminuye cuando se consideran semillas del mismo o diferente fruto (89[PRESERVECIRC]16%). Solamente la varianza entre familias resulta significativa (p < 0,001) y las coancestrías promedio estimadas dan cuenta que las progenies familiares no están conformadas solamente por medios hermanos. Conclusiones: Los resultados son discutidos y relacionados con la dispersión limitada del polen y semillas y su implicancia para el manejo. El estudio del sistema de fecundación de esta población del desierto chileno sugiere que la baja densidad poblacional y la fragmentación del ambiente no influirían en su capacidad de apareamiento.

RESUMEN Antecedentes: La cría de búfalas de agua para la producción de leche alcanza 41 años en el panorama pecuario cubano. Objetivos. Se realizó un análisis del comportamiento lechero, en diferentes rebaños del país y se compararon con el de la empresa Los Naranjos, se analizó el comportamiento de la Habilidad Productiva Más Probable (HPMP) y se estimaron componentes genéticos para diferentes rasgos lecheros de las búfalas pertenecientes a esa empresa en particular. Métodos: Un total de 24 907 lactancias de diferentes rebaños del país y 6 498 de la Empresa Los Naranjos que ocurrieron entre 2013 a 2020, se estudiaron mediante modelos lineales multicarácter con efectos aleatorios de padre y de la hembra que produce el registro, modelos para estimar algunos factores ambientales y genéticos que afectan la producción de leche a 100 días (L100); 200 días (L200), leche total (Ltot) y la duración de la lactancia (Dlac). Resultados: Las hembras que parieron en el año 2020 produjeron -62,1 kg y -96,2 kg de L200 y Ltot respectivamente respecto a las paridas en 2013, aun cuando la Dlac se incrementó en 15 días en el mismo periodo. Se manifestó una amplia variabilidad en la habilidad productiva más probable (HPMP), pero la evolución de este indicador en función del año de nacimiento de las búfalas fue prácticamente nula, indicando la poca presión de selección ejercida en la crianza de esta especie. Los estimados de repetibilidad (() estuvieron entre 0,372 a 0,397 para L100; L200 y Ltot, magnitudes prácticamente dos veces superiores en la empresa Los Naranjos respecto al resto del país. Los estimados de heredabilidad (h2) estuvieron entre ≈0.217±0.01 y 0.166±0,02 para L100; L200 y Ltot respectivamente con correlaciones genéticas superiores a 0,961. A partir de las diferencias esperadas en las progenies (DEP) se constató que las hijas de los mejores 20 sementales alcanzaron un DEP de +37,6±12,9 kg en L200 y +42,5±15,7 kg para Ltot. Conclusiones: Los indicadores bajo estudio no presentaron una evolución favorable, no obstante, se evidencian posibilidades para el trabajo de selección y mejora.

ABSTRACT Background: The breeding of water buffaloes for milk production reaches 41 years in the Cuban livestock panorama. Objective. An analysis of dairy behavior was carried out in different herds in the country and compared with that of the Los Naranjos enterprise, the behavior of the Most Probable Productive Ability (HPMP) was analyzed and genetic components were estimated for different dairy traits of the buffaloes belonging to that particular company. Methods: A total of 24 907 lactations from different herds in the country and 6 498 from the Los Naranjos company that occurred between 2013 to 2020, were studied using multicharacter linear models with random effects of father and the female that produces the record, models to estimate some environmental factors. and genetics that affect milk production at 100 days (L100); 200 days (L200), total milk (Ltot) and the duration of lactation (Dlac). Results: The females that gave birth in 2020 produced -62,1 kg and -96,2 kg of L200 and Ltot respectively compared to those that gave birth in 2013, even though Dlac increased by 15 days in the same period. A wide variability was manifested in the most probable productive ability (HPMP), but the evolution of this indicator depending on the year of birth of the buffaloes was practically null, indicating the little selection pressure exerted in the breeding of this species. Repeatability estimates (() were between 0,372 to 0,397 for L100; L200 and Ltot, magnitudes practically twice as high in the Los Naranjos company compared to the rest of the country. Heritability estimates (h2) were between ≈0,217±0,01 and 0,166±0,02 for L100; L200 and Ltot respectively with genetic correlations greater than 0,961. From the expected differences in the progenies (DEP), it was found that the daughters of the best 20 sires reached an EPD of +37,6±12.9 kg in L200 and +42,5±15,7 kg for Ltot. Conclusions: The indicators under study did not present a favorable evolution, however, possibilities for selection and improvement work are evident.

RESUMEN Antecedentes: Las condiciones climáticas en los países tropicales, ejercen un efecto significativo, sobre la producción de leche. Objetivo: Analizar las condiciones climáticas en la Empresa Pecuaria Genética Los Naranjos y su posible relación con el comportamiento de la producción de leche a 305 días. Materiales y métodos: Se dispuso de una base de datos de 12 625 registros de producción de leche, de vacas que tuvieron sus partos entre los años 2002 -2020 que se correspondieron con 7 711 animales. Se contó con los registros mensuales de la temperatura mínima (Tmin), media (Tmed) y máxima (Tmáx) en 0C, humedad relativa (HR) en % y se generó el índice temperatura-humedad (ITH), y a partir de este se realizó el cálculo de la Carga Calórica Acumulada (CCA) de los tres meses antes del parto. Además, se estimaron las heredabilidades (h2) y las correlaciones genéticas (rg) para las diferentes CCA. Resultados: Las medias generales obtenidas fueron: PL305: 1 624,45 ± 360.40 (kg/lactancia), ITH 76,34± 18,70 y CCA 229,21± 128,5. Todas las fuentes de variación estudiadas influyeron en forma significativa en la producción de leche a 305 días. Las h2 variaron entre 0,25 y 0,38 y las rg fueron todas positivas y más altas para los grupos de CCA más próximos. Conclusiones: Hubo relación inversa entre el ITH y la CCA con la producción de leche. Se evidencia la variabilidad genética aditiva para los diferentes grupos de CCA y las rg fueron positivas denotando cierta variabilidad genética para la adaptación al stress climático.

ABSTRACT Background: Climatic conditions in tropical countries have a significant effect on milk production. Aim: Analyze the climatic conditions at the Los Naranjos Genetic Livestock Company and its possible relationship with the behavior of milk production at 305 days. Materials and methods: A database of 12,625 milk production records was available, from cows that gave birth between the years 2002 -2020, which corresponded to 7,711 animals. There were monthly records of the minimum temperature (Tmin), average (Tmed) and maximum (Tmax) at 0C, relative humidity (RH) in % and the temperature-humidity index (ITH) was generated, and from this the performed the calculation of the Accumulated Caloric Load (CCA) for the three months before delivery. In addition, heritabilities (h2) and genetic correlations (rg) were estimated for the different CCAs. Results: The general means obtained were: PL305: 1 624.45 ± 360.40 (kg/lactation), ITH 76.34 ± 18.70 and CCA 229.21 ± 128.5. All sources of variation studied significantly influenced milk production at 305 days. The h2 ranged between 0.25 and 0.38 and the rgs were all positive and higher for the closer CCA groups. Conclusions: There was an inverse relationship between ITH and CCA with milk production. Additive genetic variability is evident for the different CCA groups and the rg were positive denoting certain genetic variability for adaptation to climatic stress.