ABSTRACT Sweet sorghum (Sorghum bicolor L.) is a promising energy crop for bioethanol production. This study aimed to investigate the influence of genetic structure on the adaptability and phenotypic stability of sweet sorghum lines and hybrids regarding the main agro-industrial traits, as well as selecting hybrids that associate high ethanol yield and yield stability in different growing environments. A total of 45 genotypes were evaluated in experiments conducted in a 5×9 triple alpha lattice design in three locations in the state of Minas Gerais, Brazil. The following traits were measured: fresh matter production, juice extraction percentage, total soluble solids content, tons of Brix per hectare, and ethanol production. Adaptability and phenotypic stability were assessed by the Wricke and Annicchiarico methods. Sweet sorghum adaptability and phenotypic stability depend on genotype genetic structure, with hybrids being more stable than parental lines. Additionally, H2x9 and H3x8 were the most promising hybrids. Sorghum L. L production agroindustrial agro industrial environments 4 59 5 9 5× Gerais Brazil measured percentage content hectare methods Additionally Hx H x H2x H3x

RESUMO O sorgo sacarino (Sorghum bicolor (L.)) é uma cultura energética promissora para a produção de bioetanol. O objetivo deste trabalho foi verificar a influência da estrutura genética na adaptabilidade e estabilidade fenotípica de linhagens e híbridos de sorgo sacarino quanto aos principais caracteres agroindustriais, bem como selecionar híbridos que associem elevado rendimento de etanol e estabilidade produtiva nos ambientes de cultivo testados. Foram avaliados 45 genótipos em experimentos conduzidos no delineamento alfa-látice triplo 5 x 9 em três localidades do Estado de Minas Gerais, Brasil. Foram mensurados os caracteres produção de massa verde, porcentagem de extração de caldo, teor de sólidos solúveis totais, toneladas de brix por hectare e produção de etanol. A adaptabilidade e a estabilidade fenotípica foram aferidas pelos métodos de Wricke e Annicchiarico. Observou-se que a adaptabilidade e estabilidade fenotípica em sorgo sacarino depende da estrutura genética dos genótipos, no qual os híbridos foram mais estáveis do que as linhagens parentais. Além disso, os híbridos H2x9 e H3x8 foram os mais promissores. Sorghum L. L (L.) bioetanol agroindustriais testados 4 alfalátice alfa látice Gerais Brasil verde caldo totais Annicchiarico Observouse Observou se parentais disso Hx H H2x H3x promissores (L. (L

Resumo O objetivo deste trabalho foi propor a utilização de distribuições tradicionais com base em modelos de regressão distribucional, para analisar a produtividade do milho. O experimento foi realizado em um delineamento alfa látice, com três repetições e 24 blocos. Os dados usados referem-se a 102 plantas de milho que são parte da coleção permanente do Centro de Desenvolvimento Científ ico e Tecnológico para a Agr icultura, da Universidade Federal de Lavras. Para a avalição da produtividade do milho utilizaram-se as seguintes variáveis explicativas: peso de 100 sementes, altura da planta, altura da espiga e dias para a maturação. As análises iniciais envolveram o ajuste de quatro distribuições (gama, gama generalizada, inversa Gaussiana e inversa Gaussiana generalizada) aos dados, em que a dist r ibuição gama foi a que melhor se ajustou, com base nos critérios de informação de Akaike e bayesiano (AIC e BIC). Notavelmente, a altura da espiga tem uma influência considerável sobre a variabilidade da produtividade porque conforme a altura aumenta, a produtividade diminui, enquanto as covariáveis peso de 100 sementes e dias para a maturação explicam a média crescente da produtividade. A análise residual mostra que o modelo baseado na distribuição gama é adequado para explicar os dados e fornecer informações úteis para a pesquisa e a prática agrícolas. distribucional látice 2 blocos referemse referem 10 icultura Lavras utilizaramse utilizaram explicativas planta gama, (gama generalizada ajustou AIC BIC. BIC . BIC) Notavelmente aumenta diminui agrícolas 1

Abstract The objective of this work was to propose the use of traditional models based on distributional regression models to analyze maize productivity. The experiment was carried out in an alpha lattice design, with three replicates and 24 blocks. Data used refer to 102 maize plants from the permanent collection of the Centro de Desenvolvimento Científico e Tecnológico para a Agricultura of the Universidade Federal de Lavras. For the maize productivity evaluation, the following explanatory variables were used: weight of 100 seed, plant height, ear height, and days to maturation. The initial analyses involved the fitting of four distributions (gamma, generalized gamma, inverse Gaussian, and generalized inverse Gaussian) to the data, in which the gamma distribution showed the best fit based on the Akaike and Bayesian information criteria (AIC and BIC). Cob height has a considerable influence on the productivity variability because as cob height increases, the productivity variability decreases, whereas the covariates weight of 100 seed and days to maturity explain the increasing average of the productivity. The residual analysis shows that the model based on gamma distribution is suitable for explaining the data and providing useful insights for agricultural research and practice. design 2 blocks 10 Lavras evaluation maturation (gamma Gaussian AIC BIC. BIC . BIC) increases decreases practice 1

Abstract The objective of this work was to quantify the genetic potential of full-sib maize progenies subjected to a reciprocal recurrent selection, in order to obtain high-yielding hybrids. The experiment was carried out in the alpha lattice design, with three replicates and 24 blocks. One hundred and two full sib maize progenies, from the crossing of two populations and two checks, were evaluated for the following traits: grain yield, seed mass, number of ears per plant, days to maturity, days to anthesis, days to silking, anthesis-silking interval, ear height, plant height, ear position, and stem lodging. Genetic parameters were estimated through REML/BLUP and multivariate analyses (correlation and similarity network, cluster heat map, and genetic gains). There are genetic variability and divergent clusters among the studied full-sib maize progenies. Seed mass, number of ears per plant, and anthesis silking interval are the traits that most contribute to the improvement of grain yield and divergence among the full-sib maize progenies. Genetic potential should be exploited through the selection and recombination in reciprocal recurrent selection to obtain high-yielding hybrids. fullsib highyielding high yielding hybrids design 2 blocks checks mass maturity anthesissilking height position lodging REMLBLUP REML BLUP correlation network map gains. gains . gains)

Resumo O objetivo deste trabalho foi quantificar o potencial genético de progênies de irmãos germanos de milho, em uma seleção recorrente recíproca, para obtenção de híbridos com alto rendimento. O experimento foi realizado em delineamento alfa látice, com três repetições e 24 blocos. Foram avaliadas 102 progênies de irmãos germanos de milho, do cruzamento de duas populações e duas testemunhas, quanto às seguintes características: produtividade de grão, massa de sementes, número de espigas por planta, dias para a maturação, dias para o florescimento masculino, dias para o florescimento feminino, intervalo de florescimento, altura da espiga, altura da planta, posição da espiga e acamamento do caule. Os parâmetros genéticos foram estimados via REML/BLUP e análises multivariadas (rede de correlações e similaridade, agrupamento de mapa de calor e ganhos genéticos). Há variabilidade genética e agrupamentos divergentes entre as progênies de irmãos germanos de milho estudadas. A massa de sementes, o número de espigas por planta e o intervalo de florescimento são as características que mais contribuem para o melhoramento da produtividade e a divergência entre progênies de irmãos germanos de milho. O potencial genético deve ser explorado por meio de seleção e recombinação, na seleção recorrente recíproca, para a obtenção de híbridos de alto rendimento. recíproca rendimento látice 2 blocos 10 testemunhas grão sementes maturação masculino feminino caule REMLBLUP REML BLUP rede similaridade genéticos. . genéticos) estudadas recombinação 1

RESUMEN La Orinoquía colombiana y en particular, la subregión de la Altillanura presenta ventajas comparativas y competitivas para la producción de soya (condiciones edafoclimáticas, relación costo-beneficio, área potencial y ubicación), alimento esencial por su contenido proteico (~37%), especialmente para aves y cerdos. Sin embargo, las alternativas varietales adaptadas y de alto rendimiento de grano son escasas para esta vasta región. Por ello, la presente investigación fue orientada hacia la selección de líneas mejoradas o variedades potenciales con alto mérito genético mediante la aplicación del mejor predictor lineal insesgado estandarizado (REML/BLUPe). Se evaluaron 60 líneas avanzadas y cuatro variedades comerciales en un diseño Alfa látice 8x8. El rendimiento de grano (RG) osciló entre 1117 y 4431 kg ha-1, el promedio poblacional fue de 2682 kg ha-1 y los predictores BLUPe oscilaron entre 5.37 y -3.71. Con una significancia t del 5% (1.67) y un comparador de predictores (t1-t2)≥1.67 (√2), se identificaron 6 líneas sobresalientes con BLUPe superiores a la media (P<0.05) y RG>3500 kg ha-1. En orden descendente el RG fue: L-041 (4431), L-019 (4326), L-104 (3923), L-149 (3832), L-202 (3536) y L-201 (3519 kg ha-1). El predictor estandarizado BLUPe permitió una selección efectiva (92%) de líneas.

ABSTRACT The Colombian Orinoquía and the Altillanura subregion show comparative and competitive advantages for soybean production (edaphoclimatic conditions, cost-benefit ratio, potential area, and location) essential food with a high protein content (~37%) and used mostly for poultry and pig nutrition. However, this immense region has scarce varietal alternatives of high grain yield and quality that are adapted to its climatic and edaphic conditions. The current research is based on the selection of superior lines or potential varieties with high genetic merit using the restricted maximum likelihood/standardized best linear unbiased predictor (REML/BLUPe) procedure. Sixty advanced lines and four commercial varieties were tested in an 8x8 alpha lattice design. Grain yield (GY) oscillated between 1,117 and 4,431 kg ha-1, the population average yield was 2,682 kg ha-1, and BLUPe predictors ranged between 5.37 and -3.71. With a t-test at a significance of 5% (1.67) and a predictor comparator of (t1-t2)≥1.67 (√2), six outstanding lines were identified with superior BLUPe values compared to the mean (P<0.05) and GY>3,500 kg ha-1. In descending order (kg ha-1), the GY was: L-041 (4,431), L-019 (4,326), L-104 (3,923), L-149 (3,832), L-202 (3,536), and L-201 (3,519 kg ha-1). The BLUPe standardized predictor allowed an effective selection (92%) of lines.

RESUMEN La expansión del cultivo de soya en Colombia genera la necesidad de buscar variedades con alto mérito genético y su mejoramiento, la generación de variedades con rendimientos competitivos y con alta calidad de grano, adaptadas a las condiciones del trópico bajo. El objetivo fue determinar, mediante herramientas biométricas, los parámetros genéticos y las ganancias esperadas, en caracteres cuantitativos de interés, para el proceso de mejora de soya. Se evaluaron 60 líneas y 4 variedades comerciales, en un diseño alfa látice 8x8, en oxisoles de la Altillanura. La estimación de los parámetros, se realizó mediante la aplicación de modelos mixtos, con ajuste de efectos aleatorios, por el método REML. Se observó amplia variabilidad genética para todos los rasgos evaluados, exceptuando la altura de planta. Se registraron valores altos de heredabilidad, para los caracteres de floración y madurez. En los componentes de rendimiento, la heredabilidad fue alta para número de vainas y peso de 100 granos. El efecto ambiental fue bajo, con valores cercanos o superiores a 1, con excepción de abortos embrionarios, número de vainas vanas y rendimiento de grano. La ganancia genética, como porcentaje de la media fue alta, para altura de planta; moderada, para rendimiento de grano y baja, para el resto de los caracteres. La heredabilidad y la ganancia moderadas de rendimiento de grano indican una acción aditiva de los genes, ideal para la selección recurrente. Los caracteres más discriminantes en las condiciones evaluadas fueron rendimiento de grano, peso de 100 granos y número de vainas.

ABSTRACT Soybean cultivation expansion in Colombia has generated the need to seek varieties with high genetic merit. A soybean genetic breeding program seeks to generate varieties with competitive and sustainable yields, and high-quality grain adapted to the conditions of the low tropics. The aim was to determine the genetic parameters and expected gains in quantitative traits of interest in a soybean breeding process using biometric tools. Sixty lines and four commercial varieties were evaluated in an 8x8 alpha lattice design (genotypes x blocks) planted in oxisols from the Altillanura region of Colombia. The estimation of the parameters was performed by applying mixed models with a random-effects adjustment through the REML method. Wide genetic variability was observed for all the evaluated traits, except for plant height. High heritability values were registered for the characters at flowering and maturity. Heritability was high for yield components such as the number of pods and the weight of 100 grains. Overall, the environmental effect was low, with values close to or higher than 1, except for embryonic abortions, number of empty pods, and grain yield. The genetic gain as a mean percentage was high for plant height, moderate for grain yield, and low for the rest of the characters. Moderate heritability and grain yield gain indicate an additive action of the genes ideal for recurrent selection. The most discriminating characters in the evaluated conditions were the grain yield, weight of 100 grains, and number of pods.

Abstract Knowledge of the genetic variability and yield heritability and its components within the plant breeding allows to optimize the selection process. The objective of the research was to determine the genetic variability of yield and its components, as well as their correlations to identify selection criteria for increased grain productivity. 19 genotypes, planted in the spring-summer cycle, were used in 7 locations of rainfed in Mexico’s High Valleys. The experimental design was Alpha lattice with two repetitions in each environment. The experimental unit was four grooves 3 m long with a separation of 30 cm. The variables evaluated were: days at maturity, plant height, grains per spigot, number of spikes of wheat and grains per square meter, as well as harvest index, weight of a thousand grains and grain yield. The highest coefficients of genetic variation 20.8 and 18.4 were for grain and grain yield per spigot, respectively. But the highest genetic variations and heritability are presented by the weight of a thousand grains and grains per spigot which facilitates the selection of these characters. The yield had significant correlations with number of grains per square meter, grains per spigot, number of spikes and harvest index with values of 0.92, 0.57, 0.54 and 0.54, respectively. So, they can be used as selection criteria to promote productivity. For this group of genotypes, it is necessary to increase the genetic variability for spigot per square meter and weight of a thousand grains. It is proposed to the genotypes Don Carlos M2015, 6, 11 and 8 as genetic sources to increase the weight of grain, number of grains per spike, greater number of spikes and grains per square meter to promote grain yield.

Resumen El conocimiento de la variabilidad genética y heredabilidad del rendimiento y sus componentes dentro del fito mejoramiento permite optimizar el proceso de selección. El objetivo de la investigación fue determinar la variabilidad genética del rendimiento y de los componentes, así como sus correlaciones para identificar criterios de selección para mayor productividad de grano en trigo harinero. Se utilizaron 19 genotipos, sembrados en el ciclo primavera-verano en siete localidades de temporal en los Valles Altos de México. El diseño experimental fue alfa látice con dos repeticiones en cada ambiente. La unidad experimental fue de cuatro surcos de 3 m de longitud con una separación de 30 cm. Las variables evaluadas fueron: días a madurez, altura de planta, granos por espiga, número de espigas y granos por metro cuadrado, así como índice de cosecha, peso de mil granos y rendimiento de grano. Los mayores coeficientes de variación genética 20.8 y 18.4 fueron para rendimiento de grano y granos por espiga, respectivamente. Pero las variaciones genéticas y herededabilidades más altas las presento el peso de mil granos y granos por espiga lo cual facilita la selección de estos caracteres. El rendimiento presentó correlaciones significativas con número de granos por metro cuadrado, granos por espiga, número de espigas e índice de cosecha con valores de 0.92, 0.57, 0.54 y 0.54, respectivamente, que se pueden utilizar como criterios de selección para la productividad. Para este grupo de genotipos es necesario incrementar la variabilidad genética para espigas por metro cuadrado y peso de mil granos. Se propone a Don Carlos M2015, 6, 11 y 8 como fuentes genéticas para incrementar el peso de grano, número de granos por espiga, mayor número de espigas y granos por metro cuadrado para el rendimiento.

Abstract Drought stress is one of the main causes of the reduction in maize yield in the tropics, mainly in agriculture that depends on rain, which requires the generation of genotypes with tolerance to drought. The objectives of the research were to quantify the agronomic response of a group of segregating S2 lines of corn in irrigated and drought environments, as well as to select lines with tolerance to water deficit, based on two indices and the average yield of both environments. The study genotypes were 96 segregating S2 lines, two control lines and two lines not selected for drought. The lines were evaluated under irrigation and induced drought using a Latice Alpha design with four replications, in Ayala, Morelos, Mexico. 10 morphological variables were measured and drought susceptibility indices (ISS) and tolerance index (IT) were estimated. Based on the grain yield in irrigation (3.14 t ha-1), a reduction of 77.7% of the yield in drought (0.7 t ha-1) was observed. The ISS and IT indices identified the LUM69, LUM82 and LUM30 lines as drought tolerant, only LUM69 showed a competitive yield in both environments. The ISS and IT index as criteria to identify tolerant genotypes did not select the lines with the best grain yield under irrigation conditions, so the average yield through moisture environments should be included in the selection criteria.

Resumen El estrés por sequía es una de las principales causas de la reducción del rendimiento del maíz en los trópicos, principalmente en la agricultura que depende de lluvias, por lo que se requiere generar genotipos con tolerancia a sequía. Los objetivos de la investigación fueron cuantificar la respuesta agronómica de un grupo de líneas S2 segregantes de maíz en ambientes de riego y sequía, así como seleccionar líneas con tolerancia al déficit hídrico, con base en dos índices y al promedio de rendimiento de ambos ambientes. Los genotipos de estudio fueron 96 líneas S2 segregantes, dos líneas testigo y dos líneas no seleccionadas para sequía. Las líneas se evaluaron bajo riego y sequía inducida usando un diseño Látice Alfa con cuatro repeticiones, en Ayala, Morelos, México. Se midieron 10 variables morfológicas y se estimaron los índices de susceptibilidad a la sequía (ISS) y el índice de tolerancia (IT). Con base en el rendimiento de grano en riego (3.14 t ha-1), se observó una reducción de 77.7% del rendimiento en sequía (0.7 t ha-1). Los índices ISS e IT identificaron a las líneas LUM69, LUM82 y LUM30 como tolerantes a sequía, solo LUM69 mostró un rendimiento competitivo en ambos ambientes. Los índices de ISS e IT como criterio para identificar genotipos tolerantes, no seleccionaron a las líneas con mejor rendimiento de grano bajo condiciones de riego, por lo que se debe incluir en los criterios de selección al promedio de rendimiento a través de los ambientes de humedad.

Abstract Corn is susceptible to drought; a solution strategy is to generate tolerant lines from a segregating population to obtain hybrids or synthetic varieties, so the objectives were to select high yield and short ASI lines based on the irrigation-drought system, to estimate heritability and correlation of quantitative traits. The crossing of the Ac7643 × B39 lines, derived in 193 S1, lines which, together with witness and parents, were evaluated under the alpha-lattice design in a 14 × 14 arrangement with two repetitions in two locations in Morelos, Mexico. The variables were flowering male (MF) and female (FF), anthesis-silking interval (ASI), plant height (HP) and cob (HC), as well as grain yield (GY). We observed a 40 % reduction in GY under drought (0.75 t ha-1) with respect to the irrigation environment (1.26 t ha-1). The ASI was five and two days in drought and irrigation environments, respectively. The heritability for GY and ASI was 0.41. There are lines with transgressive inheritance for GY and ASI. The correlation of the GY with FF and ASI was -0.23 ** and -0.37 **, respectively. The germplasm can generate a synthetic variety or drought tolerant hybrids.

Resumen El maíz es susceptible a la sequía, una estrategia de solución es generar líneas tolerantes a partir de una población segregante para obtener híbridos o variedades sintéticas, por ello los objetivos fueron seleccionar líneas de rendimiento alto y ASI corto con base al sistema riego-sequía, estimar la heredabilidad y la correlación de caracteres cuantitativos. El cruzamiento de las líneas Ac7643 y B39 derivó 193 líneas S1, estas líneas junto con el testigo y progenitores se evaluaron bajo el diseño alfa látice en un arreglo 14 × 14 con dos repeticiones en dos localidades de Morelos, México. Las variables fueron floración masculina (FM) y femenina (FF), intervalo antesis-emergencia de estigmas (ASI), altura de planta (AP) y mazorca (AM); y rendimiento de grano (RG). Se observó reducción del 40 % en RG bajo sequía (0.75 t ha-1) con respecto a riego (1.26 toneladas ha-1), el ASI fue de 5 y 2 d en sequía y en riego, respectivamente. La heredabilidad para RG y ASI fue de 0.41. Existen líneas con herencia transgresiva para RG y ASI. La correlación del RG con FF y ASI fue de -0.23**y -0.37**, respectivamente. El germoplasma puede generar una variedad sintética o híbridos tolerantes a sequía.

To increase yield, breeding programs must search for innovative and efficient methodologies for the development and selection of superior genotypes. Therefore, this study aimed to compare the single- and multiple-trait best linear unbiased prediction (BLUP) in genetic selection of parents and hybrids of grain sorghum. For this, an experiment conducted in alpha-lattice design with two replications was used. Flowering time (FT), plant height (PH), and grain yield (GY) were evaluated in 502 grain sorghum hybrids obtained by the cross of ten restorer lines and 54 male-sterile lines. Variance components were estimated via restricted maximum likelihood (REML). Significant effects of restorer lines, of male-sterile lines, and of specific combining ability were detected by the likelihood ratio test (LRT). The estimates of variance components, genetic parameters, and correlations were similar when obtained via single- and multiple trait BLUP. Considering hybrids, the multiple-trait BLUP resulted in slightly higher predicted selection gain for the three evaluated traits and, therefore, can be efficiently applied in the genetic selection of grain sorghum.

Para incrementar el rendimiento, los programas de mejoramiento deben buscar metodologías innovadoras y eficientes para el desarrollo y la selección de genotipos superiores. De esta forma, este estudio tuvo como objetivo comparar la mejor predicción lineal no viciada (BLUP) mono y múltiple característica, en la selección genética de parentales e híbridos de sorgo granelero. Para esto, fue usado un experimento con diseño alfa latice con dos repeticiones. Se evaluó el tiempo de floración (FT), la altura de planta (AP) y el rendimiento de granos (GY) en 502 híbridos de sorgo, obtenidos por el cruzamiento entre diez líneas restauradoras y 54 líneas macho estériles. Los componentes de varianza se estimaron mediante el método de máxima verosimilitud restringida (REML). Observamos que varias veces el BLUP múltiple característica da como resultado estimaciones de correlación genética más precisas. En este trabajo, se encontraron mayores correlaciones entre FT y GY a través de BLUP múltiple característica. Estos resultados llevaron a mayores ganancias genéticas para la selección de híbridos en comparación con BLUP mono característica.

Abstract In Mexico 7.5 million hectares of corn are grown, with an average grain yield of 3.2 t ha-1, a strategy to increase yield is the use of improved varieties. The objectives of this study were 1) estimate genetic parameters in a segregating population of tropical maize; 2) select S1lines based on grain yield and earliness; and 3) determine the phenotypic and genetic correlation between traits. The germplasm under study consisted of 193 segregating S1 lines, parents and a control, S1 lines come from the F2 population from crossing Ac7643 x B-39. The lines were evaluated under irrigation using an alpha lattice design with two replications during the spring-summer 2013 and autumn-winter 2013/2014 cycle, in Ayala, Morelos. The variables recorded were days to male (FM) and female silking (FF), floral synchrony (SF), plant height (AP) and cob (AM) and grain yield (RG). The results indicate that the coefficient of additive genetic variation for RG was 17% and for FM 4%; heritability for the same traits was 0.42 and 0.80, respectively. The expected genetic gain for RG was 0.143 t ha-1 and for FM -0.62 d. The LUM-80 line turned with positive transgressive inheritance in RG. Phenotypic and genetic correlations between RG and the rest of the traits were low. The high degree of genetic variability present in the segregating population allows continuing with the breeding program.

Resumen En México se cultivan 7.5 millones de hectáreas con maíz, con un rendimiento de grano promedio de 3.2 t ha-1, una estrategia para incrementar el rendimiento es el uso de variedades mejoradas. Los objetivos del presente estudio fueron: 1) estimar los parámetros genéticos en una población segregante de maíz tropical; 2) seleccionar líneas S1 con base en el rendimiento de grano y precocidad; y 3) determinar la correlación fenotípica y genética entre caracteres. El germoplasma de estudio fueron 193 líneas S1 segregantes, los progenitores y un testigo, las líneas S1 provienen de la población F2 de la cruza de Ac7643 x B-39. Las líneas se evaluaron bajo riego usando un diseño látice alfa con dos repeticiones, en los ciclos primavera-verano 2013 y otoño-invierno 2013/2014, en Ayala, Morelos. Las variables registradas fueron días a floración masculina (FM) y femenina (FF), sincronía floral (SF), altura de planta (AP) y mazorca (AM), y rendimiento de grano (RG). Los resultados indican que el coeficiente de variación genético aditivo para RG fue de 17% y en FM de 4%; la heredabilidad para los mismos caracteres resultó de 0.42 y 0.80, respectivamente. La ganancia genética esperada para RG fue de 0.143 t ha-1 y para FM de -0.62 d. La línea LUM-80 resultó con herencia transgresiva positiva en RG. Las correlaciones fenotípicas y genéticas entre RG y el resto de caracteres fueron bajas. El alto grado de variabilidad genética presente en la población segregante permite continuar con el programa de mejoramiento genético.

El objetivo de este trabajo fue determinar la adaptación de híbridos experimentales de maíz en Costa Rica. Se evaluaron veinticuatro híbridos experimentales de grano blanco en las condiciones agroecológicas de bosque tropical húmedo, durante el período 2009-2011, en las localidades de Concepción, Guagaral, Chánguena, El Águila, Veracruz, Los Chiles y Upala, con temperaturas entre 26 y 35°C y una precipitación entre los 2700-3200 mm, esto con el fin de obtener el rendimiento y respuesta a los principales factores abióticos y bióticos. Se empleó un diseño de alfa látice con tres repeticiones. Los híbridos fueron evaluados en dos ciclos de siembra por localidad y por año. Los resultados del análisis combinado indicaron diferencias significativas al 0,05 entre genotipos y el gráfico del AMMI-biplot evidenció que los materiales con mayor estabilidad fueron: CLQRCWQ121/CLQR- CWQ122)//CML491 (QPM); CML494/CML495 (Normal); (CLQRCWQ121/CLQRCWQ26)//CML491 (QPM); (CL- QRCWQ121/CML502)//CML491 (QPM) con rendimientos promedio de 9,3; 9,0; 8,7 y 8,8 t/ha, respectivamente. Las localidades donde se obtuvo mayor rendimiento fueron El Águila y Guagaral, 9,8 y 8,5 t/ha, respectivamente. En cuanto a la interacción de localidades y genotipos el AMMI biplot mostró que El Águila y Guagaral tuvieron condiciones agro- climáticas más favorables para la expresión del potencial de los híbridos evaluados. Por su parte, Veracruz y Concepción presentaron condiciones agroclimáticas menos favorables para el desempeño de los materiales. La interacción genotipo x ambiente tuvo un valor de 62,1% en la prueba de Gollob.

The objective of this work was determine the adaptation of experimental maize hybrids in Costa Rica. Twenty four white grain experimental hybrids were evaluated in agroecological conditions of humid tropical forest during 2009-2011, at Concepción, Guagaral, Chánguena, El Águila, Veracruz, Los Chiles and Upala with temperatures between 26 and 35°C and rainfall between 2700-3200 mm, in order to evaluate its performance, yield and adaptation to major abiotic and biotic conditions. Trials were established in twelve locations using an alpha lattice design with three replications. The hybrids were evaluated in two planting cycles per location per year. The results of the combined analysis indicated significant differences between genotypes at 0.05, and AMMI-biplot graphs showed that the more stable materials were: CLQRCWQ121/ CLQRCWQ122)//CML491 (QPM); CML494/CML495 (Normal); (CLQRCWQ121/CLQRCWQ26)//CML491 (QPM); (CLQRCWQ121/CML502)//CML491 (QPM) with average yields of 9.3, 9.0, 8.7 and 8.8 t/ha, respectively. The locations where yield was higher were Guagaral and El Águila with 9.8 and 8.5 t/ha, respectively. As for the interaction of locations and genotypes, AMMI-biplots showed that locations Guagaral and El Águila offered more favorable growing conditions for the expression of the potential of the hybrids evaluated. Meanwhile, Veracruz and Concepción had less favorable growing conditions for the performance of the materials. AMMI analysis showed that PCA1 explains significantly genotype x environment interaction with a value of 62.1% in the test Gollob.