Abstract: The growth habit in bread wheat (spring and winter) is mainly determined by the process of vernalization, regulated by the Vrn genes. Several studies suggest the involvement of other genes in this differential trait. Therefore, the aim of this research was the genomic identification of regions with a possible functional relationship to growth habit. A genome wide association study (GWAS) was performed by using two different approaches: a) FarmCPU (Fixed and random model Circulating Probability Unification) and b) BLINK (Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway), both implemented in the GAPIT package of R. The source was a data set of 25 681 single nucleotide polymorphism loci (SNP’s) from 7 757 accessions of T. aestivum stored in the CIMMYT germplasm bank and classified according to growth habit. A total of 593 SNP’s markers strongly associated to their growth habit was identified (p < 0.01). But only 70 markers formed association blocks (BA) within 11 chromosomes. As expected, at least one block was located close to the Vrn1 gene of the 5A chromosome. Additionally, 20 genomic regions (BA) were identified with putative functional relationship to growth habit, with response stress proteins involved in acclimation and de-acclimation processes. The findings suggest of new genes implicated in the growth habit for Triticum aestivum and its predictive potential for unclassified genetic accessions.

Resumen: El hábito de crecimiento de los trigos harineros (primavera e invierno) está determinado primordialmente por el proceso de vernalización, regulado por los genes Vrn. Algunos estudios sugieren la implicación de otros genes en la diferenciación de dicha característica. Por ello, se tiene por objetivo la identificación genómica de regiones con una posible relación funcional al hábito de crecimiento. Se realizó un estudio de asociación del genoma completo (GWAS) con dos enfoques de análisis: a) FarmCPU (Unificación de Probabilidad Circulante de Modelo fijo y aleatorio) y b) BLINK (Información Bayesiana y Desequilibrio de ligamiento Anidado Iterativamente) implementados en el paquete GAPIT de R. Se utilizaron datos de 25 681 loci de polimorfismo de un solo nucleótido (SNP’s) de 7 757 colectas de T. aestivum del banco de germoplasma del CIMMYT clasificadas en cuanto a su hábito de crecimiento. Se identificaron 593 marcadores SNP’s con una alta asociación al hábito de crecimiento (p < 0.01). Pero solo 70 marcadores formaban bloques de asociación (BA) en 11 cromosomas. Como se esperaba, se identificó un BA cercano al gen Vrn1 en el cromosoma 5A. Adicionalmente se identificaron 20 regiones genómicas (BA) con asociación al hábito de crecimiento, en las que se detectó la presencia de proteínas de respuesta al estrés implicadas en procesos de aclimatación y des-aclimatación. Los resultados sugieren la participación de nuevos genes en la determinación del hábito de crecimiento en Triticum aestivum y su potencial predictivo en colectas no clasificadas.

El riesgo de los ganaderos familiares que pastorean en el Área Protegida Esteros de Farrapos aumenta en función de la sinergia entre las inundaciones y la disminución de las áreas de pastoreo fuera del estero. En este trabajo se consideró la frecuencia de inundaciones determinando la altura de lámina de agua del río Uruguay en un período de ocho años y el número de días en que la altura del agua excedió los umbrales que manejan los productores. El trabajo analiza las formas de internalizar el riesgo que tienen los productores ganaderos familiares. El riesgo se evaluó con el índice holístico de riesgo (Barrera et al., 2007) que combina amenaza, capacidad de respuesta y vulnerabilidad. Los umbrales de altura de agua, se determinaron mediante entrevista en profundidad. El agua superó el umbral de 3 msnm y el ganado debe estar fuera del estero 334 días de un total de 2914, con una distribución estacional con mayor frecuencia en el siguiente orden: primavera-verano-invierno-otoño. Cuatro productores presentan riesgo bajo, fundamentalmente por alta capacidad de respuesta; 18 riesgo medio, divididos en: alta vulnerabilidad y menor vulnerabilidad y mayor capacidad de respuesta; y tres presentan riesgo alto, por alto nivel de amenaza y vulnerabilidad y menor capacidad de respuesta. La relación amenaza-capacidad de respuesta fue inversamente proporcional y significativa. La capacidad de respuesta vinculada con principios y criterios agroecológicos permite orientar estrategias entre productores y en la gestión del área.

The risk of family farmers in the Protected Area Esteros de Farrapos (APEF) increases with synergy between flooding and reduced grazing areas outside the estuary. This study analyzed the extent of the frequency of flooding by determining the height of the water surface of the río Uruguay in a period of eight years and the number of days when the water level exceeded the thresholds handled by producers. The paper analyzes the ways livestock producers internalize the risk. The risk was analyzed with the holistic risk index (Barrera et al., 2007) that combines threat, responsiveness and vulnerability. The water height thresholds were determined by in-depth interviews. The water exceeded the threshold of 3 masl, therefore cattle have to be out of the estuary, during 334 days out of a total of 2914 presenting a seasonal distribution with major frequency in the following order: spring-summer-winter-autumn. Four producers have low risk due to high responsiveness; 18 present medium risk divided in: high vulnerability and lower vulnerability and increased responsiveness; and three producers are at a high risk due to high threat and vulnerability and lower responsiveness. The relationship threat-responsiveness was inversely proportional and significant. Responsiveness linked with agro-ecological principles and criteria helps orienting strategies between producers and managing of the area.

Plant breeding programs aimed at obtaining genotypes with high grain yield and stable in a wide range of environmental conditions face environmental factors that mask potential genotypes. The Genotype x Environment interaction (G × E) might cause the suitability of predicted genotypes to a particular environment to be inaccurate. This study modelled the G × E interaction using different statistical models in a group of hybrids of maize (Zea mays L.) evaluated in tropical environments. Twenty-nine white-endosperm hybrids were evaluated in 15 environments of tropical America, with an alpha-lattice design. Grain yield was first analyzed with a combined analysis of variance. Subsequently, the additive main effect and multiplicative interaction (AMMI) and the site regression (SREG) with analytic factors (FA) model were applied to study and model G × E and to define environments that best discriminate genotypes and allow the grouping of environments and genotypes. The AMMI method pointed out a locality from Guatemala, one from México and one from Nicaragua as the ones with highest G × E; generated four mega-environments; and defined the most stable and good-yielding hybrid. The SREG FA method proved a good predictor since it allowed the identification of four subgroups and grouped environments of different countries with similar features.

Los programas de fitomejoramiento enfocados a la obtención de genotipos con mayor rendimiento y estables en una amplia gama de condiciones ambientales enfrentan factores ambientales que enmascaran el potencial de los genotipos. La interacción genotipo × ambiente (G × A) puede hacer que esta predicción no sea precisa. El objetivo de este estudio fue modelar la interacción G × A mediante distintos modelos estadísticos, en un grupo de híbridos de maíz (Zea mays L.) en ambientes de clima tropical. Se evaluaron 29 híbridos de endospermo blanco en 15 ambientes de América tropical, con un diseño alfa-látice. La variable rendimiento se analizó primero con un análisis combinado de varianza. Posteriormente se aplicaron los métodos de efectos principales aditivos e interacción (AMMI) y de regresión en los sitios (SREG) con el modelo de factores analítico (FA), para estudiar la interacción G × A y definir ambientes que discriminen mejor a los genotipos, y que permitan el agrupamiento de ambiente y genotipos. El análisis AMMI señaló a una localidad de Guatemala, una de México y una de Nicaragua como las de mayor interacción, identificó cuatro mega-ambientes, y definió al híbrido más estable y con buen rendimiento. El método SREG FA resultó un buen predictor porque permitió identificar cuatro subgrupos y agrupó ambientes de diferentes países con características semejantes.

The development of an integrated breeding field book (IBFieldbook) for different crops involves the generation, handling and analysis of large amounts of data. Managing the integration of environmental, pedigree, and phenotypic information for plant breeding data analyses requires appropriate and successful software that facilitates breeders, technicians, and researchers management of the vast collected field information in an easy, efficient and interactive way. Users may also need methods to exchange information with different devices used to record information in the field. Additionally, collected information needs to be analyzed inside or outside the application, and then generate reports for germplasm improvement.

El desarrollo de un sistema integrado de libros de campo para mejoramiento (IBFieldbook, por sus siglas en inglés) para diferentes cultivos incluye la generación, manejo y análisis de grandes volúmenes de datos. El manejo de integración de la información fenotípica, ambiente y pedigrí para análisis de datos requiere de un programa computacional ("software") apropiado y exitoso, que facilite a los mejoradores, técnicos e investigadores la administración de la información recolectada en el campo de manera fácil, eficiente e interactiva. Los usuarios del programa también necesitan métodos para intercambiar información con diferentes dispositivos usados para almacenar información en el campo. La información recolectada necesita además ser analizada adentro y afuera de la aplicación, y generar reportes para el mejoramiento del germoplasma.

Six species of Trifolium (T. polymorphum Poir., T. riograndense Burkart, T. argentinense Speg., T. medium L., T. pratense L. and T. repens L.) were analyzed using inter-simple sequence repeats (ISSR) markers. Six selected primers generated 186 polymerase chain reaction (PCR) products exploring 112 loci in 34 genotypes analyzed with molecular sizes ranging from 200 to 1300 bp. These primers were able to discriminate among and within species, with the PCR products being on average 41.6% species-specific and 59.9% polymorphic at the within species level. Nuclear DNA content was determined by flow cytometry and revealed variation among species. The 1Cx genome size values were calculated and were found to range from 0.46 pg (T. pratense) to 0.96 pg (T. polymorphum). Genome size values of South American species were higher than those of Eurasiatic origin. The analyses of the molecular data grouped the six species in agreement with their geographical origin and clearly differentiate T. polymorphum from T. argentinense. The Eurasiatic group showed the highest average of species-specific bands (45.3%) and the South American group exhibited the highest amount of total bands (59.7). The highest level of intra-species polymorphisms was detected in T. argentinense (92.9%), followed by T. medium (89.5%).

Na região de solos de Basalto (Salto, Uruguai: 32.5º de latitude sul e 58º de longitude oeste), estudou-se, em um delineamento em blocos casualizados com arranjo fatorial, o efeito de 3 manejos alimentares pos-desmame (MAPD: I : 1,2cm de altura da forragem disponível e 16 ovelhas/ha; II: 2,03cm de altura da forragem disponível e 5 ovelhas/ha; III: 2,5cm de altura da forragem disponível e 1 ovelha/ha) e 2 níveis de alimentacão no período de encarneiramento (NAE: campo natural: 883kg MS verde/ha, PB: 114g/kg MS e FDN: 781g/kg MS; pastagem artificial: 1270kg MS/ha, PB: 194g/kg MS e FDN: 598g/kg MS), no desempenho reprodutivo de 300 ovelhas Merino. O MAPD estendeu-se por 70 dias. O período de encarneiramento foi de 13/4-13/5/96 e os NAE foram aplicados por 30 dias, iniciando-se 15 dias antes do início do período de cobertura. O número de cordeiros nascidos/ovelha cobertas incrementou-se ao aumentar a taxa ovulatória devido ao fato de o maior número de óvulos liberados compensar a menor viabilidade destes. O número de cordeiros nascidos/ovelha coberta foi maior nas ovelhas provenientes do MAPD III (1,18, 1,11 e 0,96, MAPD III, II e I, respectivamente, P = 0,02) e naquelas que foram submetidas às pastagens artificiais durante o período de encarneiramento (1,13 e 1,03, pastagem artificial e natural, respectivamente, P = 0,10). Essas foram as que apresentaram uma tendência de valores superiores em taxa ovulatória.

In the uruguayan Basalt region, the reproductive performance of 300 Merino ewes and the effect of 3 post-weaning feeding managements (PWFM: I: 1.2 cm height of available forage and 16 ewes/ha; II: 2.03 cm height of available forage and 5 ewes/ha; III: 2.5cm height of available forage and 1 ewe/ha) as well as 2 feeding levels before and during the breeding season (FLM: native pastures: green DM/ha: 883kg, CP: 114g/kg DM, NDF: 781g/kg DM and improved pastures: DM /ha: 1270kg, CP: 194g/kg DM, NDF: 598g/kg DM) were studied with a factorial arrangement of treatments. The PWFM extended for 70 days, ewes were mated in the period from 13/4/96 to 13/5/96 and FLM were applied for 30 days, starting 15 days before beginning of breeding. There were not differences on the ovulation rate (P>0.05); however, the P values might indicate some effect of the treatments. The number of born lambs/ewe served increased with the ovulation rate because the higher number of ovulations balanced their less viability, individually considered. Actually, the number of born lambs/ewe served was higher with animals coming from PWFM III (1.18, 1.11 and 0.96, PWFM III, II and I, respectively; P = 0.02) and with the animals grazing on improved pastures at mating period (1.13 and 1.03, improved pastures and natural pastures, respectively; P = 0.10), were those which showed slight higher ovulation rate.