Diallel Analysis of Wheat Resistance to Fusarium Head Blight and Mycotoxin Accumulation under Conditions of Artificial Inoculation and Natural Infection.

Breeding resistant wheat cultivars to Fusarium head blight (FHB), caused by Fusarium spp., is the best method for controlling the disease. The aim of this study was to estimate general combining ability (GCA) and specific combining ability (SCA) for FHB resistance in a set of eight genetically diverse winter wheat cultivars to identify potential donors of FHB resistance for crossing. FHB resistance of parents and F1 crosses produced by the half diallel scheme was evaluated under the conditions of artificial inoculation with F. graminearum and natural infection. Four FHB related traits were assessed: visual rating index (VRI), Fusarium damaged kernels (FDK), and deoxynivalenol and zearalenone content in the harvested grain samples. Significant GCA effects for FHB resistance were observed for the parental cultivars with high FHB resistance for all studied FHB resistance related traits. The significant SCA and mid-parent heterosis effects for FHB resistance were rare under both artificial inoculation and natural infection conditions and involved crosses between parents with low FHB resistance. A significant negative correlation between grain yield under natural conditions and VRI (r = -0.43) and FDK (r = -0.47) under conditions of artificial inoculation was observed in the set of the studied F1 crosses. Some crosses showed high yield and high FHB resistance, indicating that breeding of FHB resistant genotypes could be performed without yield penalty. These crosses involved resistant cultivars with significant GCA effects for FHB resistance indicating that that they could be used as good donors of FHB resistance.

Cadmium tolerance in tomato: determination of organ-specific contribution by diallel analysis using reciprocal grafts.

Given the increasing problems of water and soil contamination with cadmium (Cd), it is necessary to investigate the genetic and physiological mechanisms of tolerance to this metal in different crops, which can be used for the development of effective crop management strategies. This study aimed to assess the potential of grafting as a strategy to increase Cd tolerance and reduce absorption in tomato by evaluating the contribution of the root system and aerial parts for tolerance mechanisms. To this end, reciprocal grafting and diallel analyses were used to examine the combining ability of contrasting tomato genotypes under exposure to 0 and 35 µM CdCl2. Roots and above-ground parts were found to have specific mechanisms of Cd tolerance, absorption, and accumulation. Grafting of the USP15 genotype (scion) on USP16 (rootstock) provided the greatest synergism, increasing the tolerance index and reducing the translocation index and Cd accumulation in leaves. USP163 exhibited potential for breeding programs that target genotypes with high Cd tolerance. In tomato, both Cd tolerance and accumulation in aerial parts are genotype- and tissue-specific, controlled by a complex system of complementary mechanisms that need to be better understood to support the development of strategies to reduce Cd contamination in aerial parts.

Exploring the Potential of Heterosis to Improve Nitrogen Use Efficiency in Popcorn Plants.

Nitrogen is crucial for plant growth and development, and improving nitrogen use efficiency (NUE) is a viable strategy for reducing dependence on nitrogen inputs and promoting sustainability. While the benefits of heterosis in corn are well known, the physiological mechanisms underlying this phenomenon in popcorn are less understood. We aimed to investigate the effects of heterosis on growth and physiological traits in four popcorn lines and their hybrids under two contrasting nitrogen conditions. We evaluated morpho-agronomic and physiological traits such as leaf pigments, the maximum photochemical efficiency of PSII, and leaf gas exchange. Components associated with NUE were also evaluated. N deprivation caused reductions of up to 65% in terms of plant architecture, 37% in terms of leaf pigments, and 42% in terms of photosynthesis-related traits. Heterosis had significant effects on growth traits, NUE, and foliar pigments, particularly under low soil nitrogen conditions. N-utilization efficiency was found to be the mechanism favoring superior hybrid performance for NUE. Non-additive genetic effects were predominant in controlling the studied traits, indicating that exploring heterosis is the most effective strategy for obtaining superior hybrids to promote NUE. The findings are relevant and beneficial for agro farmers seeking sustainable agricultural practices and improved crop productivity through the optimization of nitrogen utilization.

Habilidad combinatoria de los caracteres relacionados con la producción de habichuela (Phaseolus vulgaris L.)

Las variedades de habichuela cultivadas en Colombia presentan un bajo potencial de producción, por lo que se hace necesario adelantar programas de mejoramiento, cuya ejecución depende del conocimiento de la habilidad combinatoria de los cultivares disponibles. Con el objetivo de evaluar la acción génica predominante en caracteres de importancia económica, se evaluaron 15 híbridos directos y seis progenitores. Las habilidades combinatorias general (HCG) y específica (HCE), se estimaron con el Método 2 modelo 1 de Griffing, que considera a los progenitores y sus cruzamientos directos. Se midieron los caracteres: número de vainas y producción por planta, peso promedio y longitud de la vaina. Los resultados indicaron efectos genéticos aditivos para longitud de la vaina; por el contrario, el número de vainas y producción por planta, se vieron influenciados por efectos genéticos no aditivos, mientras que el peso promedio de la vaina fue controlado por efectos genéticos, tanto aditivos como no aditivos. Los progenitores 1 y 6 mostraron efectos positivos más altos de HCG, para el peso promedio y longitud de la vaina, mientras los progenitores 5 y 6, lo fueron para la producción de vainas por planta y los progenitores 4 y 5, para el número de vainas por planta. La estimación de HCE más alta para todos los caracteres, se presentó en el hibrido 1x2, siendo la más adecuada para mejorar la producción de la habichuela.

Green bean varieties grown in Colombia have low production potential, therefore it is necessary to carry out plant breeding programs, which execution depends on the knowledge of the combinatorial ability of the available cultivars. To evaluate the predominant gene action in economically important traits 15 direct hybrids and six parents were evaluated. General combining ability (GCA) and specific combining ability (SCA) were estimated with Griffing's Method 2 model 1, which considers parents and their direct crosses. The characters: number of pods and yield per plant, average weight and pod length were measured. The results indicated additive genetic effects for pod length. In contrast, pod number and yield per plant were influenced by non-additive genetic effects, while average pod weight was controlled by both additive and non-additive genetic effects. Parents 1 and 6 showed higher positive effects of HCG for average pod weight and pod length, while parents 5 and 6 for pod yield per plant and parents 4 and 5 for number of pods per plant. The highest ECGH estimation for all traits was found in the 1x2 hybrid, being the most suitable for improving bean production.

Combining ability of tropical × temperate maize inducers for haploid induction rate, R1-nj seed set, and agronomic traits.

In vivo maternal haploid induction in isolation fields is proposed to bypass the workload and resource constraints existing in haploid induction nurseries. A better understanding of combining ability and gene action conditioning traits related to hybrid inducers is necessary to set the breeding strategy including to what extent parent-based hybrid prediction is feasible. This study aimed to evaluate the following in tropical savanna in the rainy and dry seasons for haploid induction rate (HIR), R1-nj seed set, and agronomic traits: 1) combining ability, line per se, and hybrid performance of three genetic pools; 2) genetic parameters, the modes of gene action, and heterosis; and 3) the relationships of inbred-general combining ability (GCA) and inbred-hybrid performance. Fifty-six diallel crosses derived from eight maize genotypes were evaluated in the rainy season of 2021 and the dry season of 2021/2022. Reciprocal cross effects including the maternal effect barely contributed to the genotypic variance for each trait observed. HIR, R1-nj seed set, flowering dates, and ear position were highly heritable and additive inherited, while ear length showed dominant inheritance. The equal importance of additive and dominance effects was found for yield-related traits. Temperate inducer BHI306 was the best general combiner for the HIR and R1-nj seed set, followed by two tropical inducers, KHI47 and KHI54. The ranges of heterosis were trait-dependent and slightly influenced by the environment, where hybrids in the rainy season consistently had higher heterosis than those in the dry season for each trait observed. Both hybrid groups derived from tropical × tropical and tropical × temperate inducers showed taller plants, larger ear size, and higher seed sets than the corresponding parents. However, their HIRs were still below the standard check of BHI306. The implications of genetic information, combining ability, and inbred-GCA and inbred-hybrid relationships on breeding strategies are discussed.

Genotype × environment interaction obscures genetic sources of variation in seed size in Dithyrea californica but provides the opportunity for selection on phenotypic plasticity.

PREMISE: In many species, seed size influences individual fitness, but its heritability is low, impeding its evolution. In heterogeneous environments, even if heritability of seed size is low, genetic variation in phenotypic plasticity for seed size may provide the opportunity for selection, but this possibility has rarely been investigated in wild species. The evolutionary trajectory of seed size depends on whether additive, maternal, or non-additive genetic variance dominates; moreover, the expression of any of these sources of variance may be environment-dependent, reflecting genetic variation in plasticity. In this study, we examined these sources of variation in seed size and their response to drought in Dithyrea californica. METHODS: We used a diallel design to estimate variance components for seed size in three greenhouse-raised populations sampled from California and northern Mexico. We replicated diallels in two watering treatments to examine genetic parameters and genotype × environment interactions affecting seed size. We estimated general (GCA) and specific (SCA) combining ability, reciprocal effects (RGCA and RSCA), and their interactions with water availability, and we sought evidence that sexual conflict influences seed size. RESULTS: Norms of reaction revealed genetic variation in plasticity for seed size in each population. Seed size in D. californica is determined by the combination of watering treatment, GCA and RGCA; parental identity and water availability do not consistently affect seed size, and we detected no evidence for sexual conflict. CONCLUSIONS: Multiple sources of genetic variation in phenotypic plasticity for seed size have the potential to influence its evolutionary trajectory in heterogenous environments.

Additive and Non-Additive Effects on the Control of Key Agronomic Traits in Popcorn Lines under Contrasting Phosphorus Conditions.

Phosphorus is a non-renewable natural resource that will run out of reserves in the upcoming decades, making it essential to understanding the inheritance of nutrient use efficiency for selecting superior genotypes. This study investigated the additive and non-additive effects of commercially relevant traits for the popcorn crop (grain yield-GY, popping expansion-PE, and expanded popcorn volume per hectare-PV) in different conditions of phosphorus (P) availability in two locations in Rio de Janeiro State, Brazil. Six S7 lines previously selected for P use-L59, L70, and P7, efficient and responsive; and L54, L75, and L80, inefficient and non-responsive-were used as testers in crosses with 15 progenies from the fifth cycle of intrapopulation recurrent selection of UENF-14, with adaptation to the North and Northwest regions of Rio de Janeiro State. Using the Griffing diallel analysis, P use efficiency was predominantly additive in the expression of PE, and non-additive effects were prominent for GY and PV. For obtaining genotypes that are efficient for phosphorus use, it is recommended that heterosis with parents that provide additive gene accumulation for PE be explored.

The genetic basis of neurocranial size and shape across varied lab mouse populations.

Brain and skull tissues interact through molecular signalling and mechanical forces during head development, leading to a strong correlation between the neurocranium and the external brain surface. Therefore, when brain tissue is unavailable, neurocranial endocasts are often used to approximate brain size and shape. Evolutionary changes in brain morphology may have resulted in secondary changes to neurocranial morphology, but the developmental and genetic processes underlying this relationship are not well understood. Using automated phenotyping methods, we quantified the genetic basis of endocast variation across large genetically varied populations of laboratory mice in two ways: (1) to determine the contributions of various genetic factors to neurocranial form and (2) to help clarify whether a neurocranial variation is based on genetic variation that primarily impacts bone development or on genetic variation that primarily impacts brain development, leading to secondary changes in bone morphology. Our results indicate that endocast size is highly heritable and is primarily determined by additive genetic factors. In addition, a non-additive inbreeding effect led to founder strains with lower neurocranial size, but relatively large brains compared to skull size; suggesting stronger canalization of brain size and/or a general allometric effect. Within an outbred sample of mice, we identified a locus on mouse chromosome 1 that is significantly associated with variation in several positively correlated endocast size measures. Because the protein-coding genes at this locus have been previously associated with brain development and not with bone development, we propose that genetic variation at this locus leads primarily to variation in brain volume that secondarily leads to changes in neurocranial globularity. We identify a strain-specific missense mutation within Akt3 that is a strong causal candidate for this genetic effect. Whilst it is not appropriate to generalize our hypothesis for this single locus to all other loci that also contribute to the complex trait of neurocranial skull morphology, our results further reveal the genetic basis of neurocranial variation and highlight the importance of the mechanical influence of brain growth in determining skull morphology.

Evaluation of genetic behavior of some Egyption Cotton genotypes for tolerance to water stress conditions.

Water stress is a critical abiotic stress for plant reduction in arid and semiarid zones and, has been discovered to be detrimental to the development of seedlings as well as the growth and physiological characteristics of many crops such as cotton. The objectives of our study were to determine the combining ability and genetic components for five quantitative traits [(leaf area (LA), leaf dry weight (LDW), plant height (PH), fiber length (2.5 percent SL), and lint cotton yield/plant (LCY/P)] under water shortage stress, a half diallel cross between six cotton genotypes representing a wide range of cotton characteristics was evaluated in RCBD with four replications. The genotype mean squares were significant for all traits studied, demonstrating significant variation among genotypes for all characters under water shortage stress. LCY/P had the highest phenotypic and genotypic correlation co-efficient with PH, LDW, and LA shortage. The highest direct effect on lint cotton yield was exhibited by leaf area (3.905), and the highest indirect effects of all traits were through LA, with the exception of 2.5 percent SL, which was through LDW. The highest dissimilarity (Euclidean Distance) between parental genotypes was between G.87 and G.94, followed by G.87 and Menoufi. G.94 was also a well-adapted genotype, and the combinations G.87 x G.94 and G.87 x Menoufi may outperform their parents. The combining ability analysis revealed highly significant differences between parental GCA effects and F1 crosses SCA effects. The variation of GCA and SCA demonstrated the assurance of additive and non- additive gene action in the inheritance of all traits studied. In terms of general combining ability (GCA) effects, parental genotype G.94 demonstrated the highest significant and positive GCA effects for all traits studied, with the exception of 2.5 percent SL, where G.87 revealed the highest significant and positive GCA effects. The effects of specific combining ability (SCA) revealed that the cross (G.87 x2G.94) revealed stable, positive, and significant SCA for all of the studied traits.

Combining ability studies of grain Fe and Zn contents of pearl millet (Pennisetum glaucum L.) in West Africa.

Micronutrient malnutrition is a major challenge in Africa, where half a million children die each year because of lack of micronutrients in their food. Pearl millet is an important food and fodder crop for the people living in the Semi-Arid regions of West Africa. The present study was conducted to determine the stability, combining ability, and gene action conditions of the high level of Fe and Zn content in grain and selected agronomic traits. Hence, eight genotypes were selected based on the availability of grain Fe and Zn contents and crossed in a full diallel mating design. Progenies from an 8 × 8 diallel mating along with the parents were evaluated in an alpha lattice design with three replications in three locations for two years. The parental lines Jirani, LCIC 9702 and MORO, had positive significant general combining ability (GCA) effects for grain Fe concentration, while Jirani and MORO had positive significant GCA effects for grain Zn concentration. For the specific combining ability (SCA), among the 56 hybrids evaluated, only the hybrids LCIC 9702 × Jirani and MORO × ZANGO had positive significant SCA effects for grain Fe concentration across locations, and for grain Zn concentration, the hybrids Gamoji × MORO, LCIC 9702 × Jirani, and ICMV 167006 × Jirani had positive significant SCA effects. The reciprocal effects were significant for grain Zn concentration, grain yield, flowering time, plant height, test weight, and downy mildew incidence, suggesting that the choice of a female or male parent is critical in hybrid production. Grain Fe and Zn concentration, flowering time, plant height, panicle length, panicle girth, panicle compactness, and downy mildew incidence were found to be predominantly under additive gene action, while grain yield and test weight were predominantly under non-additive gene action. A highly positive correlation was found between grain Fe and Zn concentrations, which implies that improving grain Fe trait automatically improves the grain Zn content. The stability analysis revealed that the hybrid ICMV 167006 × Jirani was the most stable and high-yielding with a high level of grain Fe and Zn micronutrients.

A Digital Image-Based Phenotyping Platform for Analyzing Root Shape Attributes in Carrot.

Root shape in carrot (Daucus carota subsp. sativus), which ranges from long and tapered to short and blunt, has been used for at least several centuries to classify carrot cultivars. The subjectivity involved in determining market class hinders the establishment of metric-based standards and is ill-suited to dissecting the genetic basis of such quantitative phenotypes. Advances in digital image acquisition and analysis has enabled new methods for quantifying sizes of plant structures and shapes, but in order to dissect the genetic control of the shape features that define market class in carrot, a tool is required that quantifies the specific shape features used by humans in distinguishing between classes. This study reports the construction and demonstration of the first such platform, which facilitates rapid phenotyping of traits that are measurable by hand, such as length and width, as well as principal component analysis (PCA) of the root contour and its curvature. This latter approach is of particular interest, as it enabled the detection of a novel and significant quantitative trait, defined here as root fill, which accounts for 85% of the variation in root shape. Curvature analysis was demonstrated to be an effective method for precise measurement of the broadness of the carrot shoulder, and degree of tip fill; the first principal component of the respective curvature profiles captured 87% and 84% of the total variance. This platform's performance was validated in two experimental panels. First, a diverse, global collection of germplasm was used to assess its capacity to identify market classes through clustering analysis. Second, a diallel mating design between inbred breeding lines of differing market classes was used to estimate the heritability of the key phenotypes that define market class, which revealed significant variation in the narrow-sense heritability of size and shape traits, ranging from 0.14 for total root size, to 0.84 for aspect ratio. These results demonstrate the value of high-throughput digital phenotyping in characterizing the genetic control of complex quantitative phenotypes.

Diallelic Analysis of Tropical Maize Germplasm Response to Spontaneous Chromosomal Doubling.

Chromosome doubling is an important step in the production of maize doubled haploid (DH) lines to induce fertility in the male and female reproductive organs of haploid plants. Chromosomal doubling is routinely accomplished by treating haploid seedlings with mitosis-inhibiting chemicals. However, chromosomal doubling involves several labor-intensive steps and toxic chemicals. Spontaneous chromosomal doubling without any chemical treatments occurs at high frequency in haploids from a few maize genotypes. This study focused on elucidating the genetic components of two traits important for using spontaneous doubling in maize-breeding programs, namely, haploid male fertility (HMF) and haploid fertility (HF). In two different sets of diallel crosses, haploids were derived and assessed for HMF and HF in two environments in replicated trials. The results revealed significant genotypic variations for both traits. The general combining ability (GCA) and specific combining (SCA) were significant for both traits. Significant and positive GCA effects of up to 14% and 9% were found for HMF and HF, respectively. No significant reciprocal effects and genotype-by-environment (G×E) interactions were found for HF in both experiments, but HMF showed significant effects for both in one of the experiments. The GCA effects were more important than the SCA effects for HMF and HF across environments, implying that selection could facilitate their improvement. The high correlations between F1-hybrid performance and mid-parent values, as well as that between F1-hybrid performance and GCA effects, also supports the assumption that these traits are controlled by a few genes. SCA effects also played a role, especially when lines with low spontaneous doubling were used as parents. Overall, spontaneous doubling can be introgressed and improved in elite germplasm with selection, and it has the potential to be employed in DH pipelines.

Testers in supersweet corn lines / Avaliação de testadores em linhagens de milho superdoce

ABSTRACT: The purpose of this study was to evaluate the discriminatory capacity of tester lines for tropical corn lines converted to supersweet shrunken (sh2) gene, for the development of hybrids adapted to tropical conditions. Lines were used as female parents in crosses with three testers: open-pollinated mixed variety; supersweet line L4; supersweet commercial hybrid Tropical Plus. Four trials were carried out to evaluate topcrosses in Maringá - PR e Sabáudia - PR, Brazil in the main growing season of 2015/16. The following traits were evaluated: total ear weight (TEW, in kg), commercial ear weight (CEW, in kg) and total soluble solids (TSS, in °Brix). The GCA estimates for TEW and CEW were highest for L4. The lines Balu-114 and UEM-25 were selected based on the effects of g ̂ ifor the traits studied and should be used in the establishment of base populations for the breeding of superior lines. The s ̂ ijvalue for TEW was highest for cross BALU-182 x Tropical, while for CEW was the highest value for cross BALU-94 x Mista.

RESUMO: O presente trabalho teve como objetivo avaliar o desempenho de testadores quanto à capacidade de discriminação de linhagens tropicais convertidas à superdoce, por meio da incorporação do gene shrunken (sh2), visando a produção de híbridos adaptados às condições tropicais. As linhagens utilizadas como parentais femininos foram os testadores: variedade de polinização aberta Mista; linhagem superdoce L4; híbrido comercial superdoce Tropical Plus. Os quatro experimentos foram conduzidos em Maringá - PR e Sabáudia - PR, na safra verão de 2015/16. As características avaliadas foram: Peso de espigas totais (PET, em kg), Peso de espigas comerciais (PEC, em kg) e sólidos solúveis totais (SST, em ºBrix). A linhagem L4 foi o testador que mais proporcionou efeito de heterose. As maiores estimativas de CGC para PET e PEC foram obtidas por L4. As linhagens Balu-114 e UEM-25 foram selecionados com base nos efeitos de g ̂ i para as características estudadas e deverão ser utilizados na formação de populações base para a extração de linhagens superiores. O cruzamento BALU-182 x Tropical apresentou o maior valor de s ̂ ijpara PET, enquanto o cruzamento BALU-94 x Mista obteve o melhor valor para PEC.

Diallel analysis and prediction of untested maize single cross hybrids / Análise dialélica e predição de híbridos simples de milho não testados

Popcorn (Zea mays everta) is a popular snack food and very appreciated in Brazil, presenting higher aggregate value when compared with field corn. The aim of this study were to identify superior inbred lines and single crosses hybrids (SH) for popcorn traits, as well as the prediction of the performance of untested single cross hybrids. Sixteen maize inbred lines were crossed in a 9x7 partial diallel, but it was possible to evaluate 47 single crosses in two distinct locations. Predicted genetic values, diallel analysis and the prediction of untested HS were performed by mixed models. Deviance effects for treatments x locations were considered non-significant (p>0.05) for grain yield (GY) and popping expansion (PE), showing an average performance from the HS in the locations. Inbred lines P5-1, P3.3T, GER-P3, P9-1, P12-2 andGER-P12 were selected considering the general combining ability, and should be used for obtaining superior genotypes. Based on the non-additive effects, the single hybrid P3.3T x GERP-P12 was selected for grain yield and popping expansion, and could be exploited in future trials. Neither of the untested single crosses showed desirable performance for grain yield and popcorn expansion.

O milho pipoca (Zea mays everta) é um alimento consumido e apreciado em todo o Brasil, apresentando valor comercial superior ao do milho comum. O presente trabalho teve como objetivo identificar linhagens e híbridos simples (HS) com desempenho superior para as principais características relacionadas ao milho pipoca, além da predição do desempenho de híbridos simples não testados. Foi realizado um dialelo parcial 9x7, dos quais apenas 47 HS foram avaliados em dois locais. Os valores genéticos preditos, análise dialélica e a predição dos HS não avaliados foram realizadas via modelos mistos. Os efeitos da deviance na interação tratamentos x locais foram considerados não significativos (p>0.05) para rendimento de grãos (RG) e capacidade de expansão (CE), indicando um comportamento médio dos HS nos ambientes testados. Com base nos efeitos aditivos, as linhagens P5-1, P3.3T, GER-P3, P9-1, P12-2 e GER-P12 foram selecionados e deverão ser usadas na formação de genótipos com desempenho superior. O híbrido P3.3T x GER-P12 foi selecionadopor apresentar elevado desempenho específico para rendimento e capacidade de expansão, podendo ser utilizado em futuros experimentos. Entre os híbridos não avaliados, nenhum apresentou desempenho satisfatório para as características avaliadas.

Correlations and selection of parents to technological traits of upland cotton / Correlações e seleção de genitores para caracteres tecnológicos em algodoeiro herbáceo

ABSTRACT: Technological traits improvement of cotton fiber is a constant demand by textile industry. This research aimed to identify the potential of improved materials with high lint percentage to contribute with alleles that increase the lint percentage in Extra long staple fiber (ELS) upland cotton. Two contrasting materials for lint percentage (LP) and fiber length (FL) were used, one with long fiber and a low lint percentage (parent A) and another with high lint percentage and medium length (parent B). The following variables were evaluated: lint percentage (LP), upper half mean length (UHML), fiber uniformity (FU), fiber strength (FS), and elongation (EL). Diallel analysis was performed using the Griffing's Method 4 adapted to partial diallel. Additive effects were predominant over non-additive effects. The mean LP was higher when using parent B. The opposite occurred for UHML. A negative correlation was detected between LP and UHML, showing the difficulty of obtaining genetic gain for both traits at the same time.

RESUMO: O aprimoramento das características tecnológicas da fibra de algodão é uma demanda constante da indústria têxtil. Este trabalho teve como objetivo identificar o potencial de materiais melhorados com alta porcentagem de plumas para contribuir com alelos que aumentam a porcentagem de plumas com fibra extra longa (ELS) no algodão de terras altas. Dois materiais contrastantes para porcentagem de fibra (LP) e comprimento de fibra (FL) foram usados, um com fibra longa e uma baixa porcentagem de fibra (pai A) e outro com alta porcentagem de fibra e comprimento médio (pai B). As seguintes variáveis foram avaliadas: porcentagem de fibra (LP), comprimento médio da metade superior (UHML), uniformidade da fibra (FU), resistência da fibra (FS) e alongamento (EL). A análise dialélica foi realizada utilizando o Método 4 de Griffing adaptado para dialelo parcial. Os efeitos aditivos foram predominantes em relação aos efeitos não aditivos. O LP médio foi maior quando se usou o pai B. O oposto ocorreu para o UHML. Uma correlação negativa foi detectada entre LP e UHML, mostrando a dificuldade de obter ganho genético para ambas as características ao mesmo tempo.

Desempenho de codornas de corte em cruzamentos dialélicos / Performance of meat type quails in diallel cross

Objetivou-se com este trabalho avaliar o desempenho de quatro linhagens (L1, L2, L3 e L4) de codornas de corte em cruzamentos dialélicos. O presente estudo foi realizado nas instalações do Programa de Melhoramento de Codornas do Departamento de Zootecnia da UFVJM, no período de 16 de dezembro de 2011 a 26 de janeiro de 2012. Foram avaliados o peso corporal médio ao nascimento, aos 35 e aos 42 dias de idade; o consumo médio de dieta e a conversão alimentar do nascimento aos 35 dias e do nascimento aos 42 dias de idade. As análises dialélicas foram desenvolvidas de forma univariada, considerando-se a metodologia de dialelos completos, a partir das médias das combinações genotípicas resultantes de um experimento inteiramente ao acaso com três repetições. A capacidade geral de combinação foi significativa para todas as características avaliadas, com exceção do consumo médio de dieta e da conversão alimentar do nascimento aos 35 dias de idade. Houve efeito significativo da capacidade específica de combinação sobre o peso corporal ao nascimento (L2xL3; L2xL4; L1xL4); conversão alimentar do nascimento aos 35 dias (L1xL3; L2xL4) e do nascimento aos 42 dias (L1xL3; L2xL3; L2xL4); consumo médio de dieta do nascimento aos 35 dias de idade (L1xL3; L2xL3), o que permitiu a identificação de combinações híbridas mais favoráveis. O efeito recíproco foi significativo apenas sobre o peso ao nascimento. Com base na capacidade geral de combinação, as linhagens mais favoráveis para peso corporal foram a L1 e a L2. Para a conversão alimentar, pela capacidade específica de combinação, os cruzamentos L1xL3 e L2xL4 apresentaram o melhor resultado, enquanto para o consumo de dieta do nascimento aos 35 dias de idade, os cruzamentos L1xL3 e L2xL3 são os mais indicados.

The aim of this study was to evaluate the performance of four strains of meat type quails, designated L1, L2, L3 and L4 in diallel crosses. This study was carried out at the premises of the Genetic Improvement Program for Quails of UFVJM, from December 2011 to May 2012. The average body weight at hatch, at 35 and at 42 days old, the average daily feed intake at 35 and at 42 days old, and feed conversion at 35 and 42 days old were evaluated. Diallel analyzes were developed using univariate analyses, considering the methodology of complete diallel, from the average of the genotype combinations resulting in a complete randomized design with three replications. The combining ability analysis revealed significance for general combining ability for all traits, except for average feed intake and feed conversion at 35 days old. There was significant effect of specific combining ability for hatch weight (L2xL3; L2xL4; L1xL4); feed conversion from hatch to 35 days of age (L1xL3; L2xL4), and from hatch to 42 days (L1xL3; L2xL3; L2xL4); and average feed intake from hatch to 35 days of age (L1xL3; L2xL3), thus allowing the identification of more favorable hybrid combinations. The reciprocal effect showed significance only for hatch weight. Based on general combining ability, the strains which are more favorable for increased body weight were L1 and L2. For feed conversion, for the specific combining ability, the crosses L1xL3 and L2xL4 showed the best results, while for feed intake from hatch to 35 days old, the crosses L1xL3 and L2xL3 would be the most suitable.

Gene effect and heterosis in Capsicum baccatum var. pendulum / Efeito gênico e heterose em cruzamentos de Capsicum baccatum var. pendulum

Heterosis has been exploited in Capsicum annuum commercial hybrids; however, the use of heterosis in C. baccatum still remains to be explored, and studies related to the genetics and breeding of this species are scarce. The present study aimed to estimate the combining ability of five parents of C. baccatum var. pendulum , representatives of two distinct types of fruits (namely, lady's finger and cambuci), to calculate heterosis and to evaluate the agronomic potential of the hybrids for yield and fruit quality. The hybrids were produced from a complete diallel without reciprocals. The parents and hybrids were evaluated under field conditions in a randomized block design with three replications, and the following traits were assessed: number of fruits per plant, fruit weight, yield per plant, fruit length, fruit diameter and soluble solids. All traits were significant for general and specific combining ability, indicating that additive and non-additive effects are involved in the genetic control of these traits. The hybrid combinations between the types lady's finger and cambuci provided elongated fruits with smaller diameters and greater weight compared with the parents of the cambuci type. However, these factors did not lead to a significant increase in the yield per plant due to the decreased number of fruits except in hybrid UENF 1616 x UENF 1732. Considering only the parents and hybrids within each type of fruit, the genitor UENF 1624 (lady's finger) and the hybrid UENF 1639 x UENF 1732 (cambuci x cambuci) stood out for achieving a high yield per plant.

Embora heterose seja bem explorada na produção de híbridos comerciais de C. annuum, em C. baccatum, o uso da heterose permanece como um potencial e estudos relacionados à genética e ao melhoramento dessa espécie são escassos. Os objetivos deste trabalho foram estimar a capacidade combinatória entre cinco genitores de C. baccatum var. pendulum , representantes de dois grupos distintos de tipos de frutos (dedo-de-moça e cambuci); calcular a heterose e avaliar o potencial agronômico dos híbridos produzidos em termos de produção e qualidade dos frutos. Os híbridos foram produzidos a partir de um dialelo completo, sem recíprocos. Os genitores e os híbridos foram avaliados em condições de campo, no delineamento de blocos ao acaso, com três repetições, sendo avaliadas as seguintes características: número de frutos por planta, massa média do fruto, produção por planta, comprimento do fruto, diâmetro do fruto e teor de sólidos solúveis. Todas as características foram significativas para a capacidade geral e específica de combinação, indicando que efeitos aditivos e não-aditivos estão envolvidos no controle genético dessas características. As combinações híbridas entre os tipos dedo-de-moça e cambuci proporcionaram frutos alongados, com menores diâmetros e maior peso, quando comparado com os genitores do tipo cambuci. Contudo, esses fatores não favoreceram um aumento expressivo na produção por planta em virtude da diminuição do número de frutos, com exceção para o híbrido UENF 1616 x UENF 1732. Considerando somente os genitores e os híbridos dentro de cada tipo de fruto, destaca-se a linhagem UENF 1624 (dedo-de-moça) e o híbrido UENF 1639 x UENF 1732 (cambuci x cambuci) em relação à produção por planta.

Capacidade combinatória entre híbridos simples de milho em dialelo circulante / Combining ability in corn single-cross hybrids by circulant diallel

Onze híbridos comerciais de milho (AS 1550, DKB 214, DKB 215, DKB 330, Dow 2B150, Dow 8460, P 30F33, P 30F53, P 30P70, Penta e Premium Flex) foram intercruzados, obtendo-se 44 híbridos duplos, segundo um dialelo circulante com p=11 (onze genitores) e s=8 (intercruzados 8 a 8), avaliado em delineamento em blocos casualizados com três repetições. Foram conduzidos dois experimentos na Região Centro-sul do Paraná, nos municípios de Guarapuava e Goioxim. Os dados referentes à produção de grãos, altura média de planta e altura média de inserção de espiga foram submetidos à análise dialélica. Houve diferenças significativas entre os locais e entre os híbridos do dialelo para as três características avaliadas. Também houve efeito significativo da interação locais x híbridos do dialelo para a produção de grãos. Houve diferenças significativas para a capacidade geral de combinação (CGC) em todas as características e para a capacidade específica de combinação (CEC) apenas na produção de grãos. Destacaram-se por sua CGC os híbridos Penta, P 30F53 e Dow 8460 na produção de grãos, o híbrido AS 1550 quanto á menor altura de planta e de inserção da espiga. A melhor combinação híbrida para a produtividade foi Penta x P 30F53, por apresentar a maior média, elevada CEC e ambos os genitores terem as maiores estimativas de CGC. O genitor P 30F53 participou de três dos quatro híbridos duplos mais produtivos. É possível a obtenção de novas populações a partir de cultivares comerciais que se destacaram por sua CGC, e que, nos cruzamentos em que participaram, houve, também, estimativas favoráveis da CEC.

Estimatives of the general combining ability (CGA) and specific combining ability (SCA) among eleven commercial maize hybrids were obtained in this study. Single-cross hybrids AS 1550, DK B214, DK B215, DK B330, Dow 2B150, Dow 8460, P 30F33, P 30F53, P 30P70, Penta and Premium Flex were intercrossed in a circulant diallel scheme with p=11 (eleven parents) and s=8 (crossed 8 to 8) to obtain 44 double hybrids. These genotypes were evaluated in randomized block design with three replications. Two experiments were carried out in Center-South Paraná State, in Guarapuava and Goioxim, Brazil. The yield, plant height and ear height were obtained and submitted to diallel analysis. There were significant differences between localities and between diallel hybrids for both traits. Significant differences were observed for localities x diallel hybrids interaction for grain yield. Significant differences were detected for GCA in all characteristics and for SCA only in yield. Parents Penta, P 30F53 and Dow 8460 were outstanding for CGA values in yield, and parent AS 1550 in plant height and ear height. The best hybrid combination was Penta x P 30F53, since it showed the highest yield, high SCA value and both parents presented the highest GCA estimative. The hybrid P 30F53 was parent of three among four of the most productive double hybrids. It is possible to obtain good populations from the commercial cultivars that were outstanding because of GCA and SCA estimatives in hybrid combinations.

Genetic control on the performance of common bean differential cultivars to Colletotrichum lindemuthianum races

The aim of this work was to perform genetic control on differential cultivars Michelite, Michigan Dark Red Kidney, Perry Marrow, Cornell 49-242, PI 207262, AB 136 and G 2333 and its diallel hybrids by using Hayman's methodology. The entire F1s populations were evaluated in relation to race 89, whereas the race 31, the diallel scheme did not include the cultivar G 2333. The results showed that the additive effects were predominant for the 31 race, while non-additive effects were more important for race 89. The results demonstrated a high coefficient of genetic determination for the race 31. The G 2333, AB 136 and PI 207262 cultivars should be recommended obtaining cultivar resistant to anthracnose by backcross programs because theyshowed the highest proportion of resistant dominant alleles for the races 31 and 89.

Dentre as várias doenças que causam problemas no cultivo de feijão comum (Phaseolus vulgaris L.), uma das mais importantes é a antracnose causada pelo fungo Colletotrichum lindemuthianum (Saac. et Magn.) Scrib., a qual pode resultar em severas perdas na produtividade de grãos. O controle genético, nas cultivares diferenciais Michelite, Michigan Dark Red Kidney, Perry Marrow, Cornell 49-242, PI 207262, AB 136 e G 2333 e seus 21 híbridos dialélicos, foi obtido usando a metodologia de Hayman (1954). Todas as populações F1s foram avaliadas em relação à raça 89, enquanto que os híbridos envolvendo a cultivar G 2333 não foram avaliados com a raça 31. Os resultados demonstraram que os efeitos aditivos foram predominantes para a raça 31, enquanto os efeitos gênicos não aditivos foram mais importantes na reação de incompatibilidade das cultivares a raça 89. Os resultados ainda evidenciaram um elevado coeficiente de determinação genética para a raça 31. Os cultivares G 2333, AB 136 e PI 207262 são os mais indicados para programas de melhoramento visando à obtenção de cultivares resistentes à antracnose por possuírem maior proporção de alelos dominantes para resistência às raças 31 e 89.

Inferências genéticas em cultivares diferenciadoras de feijoeiro comun ao Colletotrichum lindemuthianum raça 69 / Genetic inferences in common bean differential cultivars to colletotrichum lindemuthianum race 69

A antracnose, causada pelo fungo Colletotrichum lindemuthianum Sacc. cet Magn, é uma das mais importantes doenças e pode causar severas perdas ao cultivo do feijão comun (Phaseolus vulgaris L.). Inferências genéticas sobre a resistência de sete cultivares diferenciais de feijão comun (Michelite, Michegan dark Red Kidney, Perry Marrow, Cornell 49-242, PI 207262, AB 136, G 2333) e seus 21 híbridos dialélicos foram obtidas em relação à raça 69, por meio da metodologia de Hayman. Os resultados mostraram que os efeitos dominantes foram superiores aos aditivos para resistência à referida raça. A ordem dos parentais em relação à concentração de genes dominantes obtida foi: G 2333, AB 136, PI 207262, Cornell 49-242, Michigan Dark Red Kidney, Perry Marrow e Michelite. Os parentais G 2333, AB 136 e PI 707262 são os mais indicados para programas de melhoramento visando à obtenção de cultivares resistentes à antracnose

A antracnose, causada pelo fungo Colletotrichum lindemuthianum Sacc cet Magn, é uma das maisimportantes doenças e pode causar severas perdas ao cultivo do feijão comum (Phaseolus vulgaris L.).Inferências genéticas sobre a resistência de sete cultivares diferenciais de feijão comum (Michelite,Michigan Dark Red Kidney, Perry Marrow, Cornell 49-242, PI 207262, AB 136, G 2333) e seus 21 híbridosdialélicos foram obtidas em relação à raça 69, por meio da metodologia de Hayman. Os resultadosmostraram que os efeitos dominantes foram superiores aos aditivos para resistência à referida raça. Aordem dos parentais em relação à concentração de genes dominantes obtida foi: G 2333, AB 136, PI207262, Cornell 49-242, Michigan Dark Red Kidney, Perry Marrow e Michelite. Os parentais G 2333, AB136 e PI 707262 são os mais indicados para programas de melhoramento visando à obtenção de cultivaresresistentes à antracnose