RESUMO O milho pipoca é uma importante cultura agrícola, consumida como petisco pela população mundial. No Brasil, a falta de cultivares com alto potencial de rendimento de grãos e elevado volume de expansão é considerada uma das principais dificuldades. Nesse contexto, o presente trabalho teve como objetivo avaliar a divergência genética entre linhagens elite de milho pipoca por meio de marcadores AFLP (Amplified Fragment Length Polymorphism), estimar a capacidade geral e específica de combinação (GCA e SCA, respectivamente) e correlacionar a distância genética com a SCA e a média dos híbridos. Para o estudo de divergência genética, foram avaliadas 45 linhagens de milho pipoca provenientes de diferentes híbridos e variedades. Posteriormente, dez linhagens foram selecionadas para análise dialélica; o rendimento de grãos (GY) e a capacidade de expansão (PE) foram avaliados em três ambientes. Com base nos marcadores AFLP, foi observada uma ampla variabilidade entre as linhagens avaliadas. Na avaliação dos híbridos, foi observado efeito significativo para GY e PE, sendo que alguns híbridos apresentaram alto potencial de GY e PE quando comparados às testemunhas comerciais. Por meio da análise dialélica, foi observado efeito significativo da GCA para GY e PE, indicando que as linhagens diferem na frequência de alelos favoráveis, com linhagens promissoras para a formação de híbridos ou variedades sintéticas. Por outro lado, para SCA, nenhum efeito significativo foi observado para essas características. A distância genética não se correlacionou com GY e Ŝij, demonstrando ausência de consistência na predição de grupos heteróticos para milho pipoca via marcadores AFLP.

ABSTRACT Popcorn is an important agricultural crop that is consumed as a snack food worldwide. In Brazil, the lack of cultivars with high potential grain yield and popping expansion volume is a vital problem. Therefore, the present study aimed to evaluate the genetic divergence among elite popcorn lines using amplified fragment length polymorphism (AFLP) markers to estimate the general and specific combining ability (GCA and SCA, respectively), and correlate the genetic distance with the SCA and hybrid means. For the genetic divergence study, 45 popcorn inbred lines of different hybrids and varieties were evaluated. Subsequently, 10 inbred lines were selected for diallel analysis; grain yield (GY) and popping expansion (PE) were evaluated in three environments. A wide variability of popcorn inbred lines was observed based on the AFLP markers. After evaluating the hybrids, a significant effect was observed for GY and PE, with some experimental hybrids with higher potential GY and PE than the commercial cultivars. From the diallel analysis, a significant effect was observed for GCA for GY and PE; therefore, the lines differed in the frequency of favorable alleles, with promising inbred lines for forming hybrids or synthetic varieties. However, for SCA, no significant effect was observed for these traits. Genetic distance did not correlate with GY and Ŝij, demonstrating an absence of consistency in the prediction of heterotic groups for popcorn using AFLP markers.

ABSTRACT The development of new popcorn cultivars that include wide adaptation, high stability and superior performance characteristics is one of the main alternatives to mitigate the effects of the genotype × environment interaction. In this sense, our main goal was to evaluate the adaptability and stability of new popcorn hybrids using Bayesian additive main effects and multiplicative interaction (BAMMI) method for grain yield (GY) and popping expansion capacity (PE) traits. We evaluated GY and PE from 45 new popcorn hybrids and three commercial cultivars (IAC–125, Pop Top and Top Ten) as checks in six different environments. Genotype × environment interaction, correlation and stability analyses were performed using Bayesian approaches. The full models tested presented the lowest deviance information criterion (DIC) values when compared to null models, indicating the presence of the genotype × environment interaction for both evaluated agronomic traits. Negative correlations were observed between GY and PE (r = –0.24, 95% highest posterior density [HPD] = –0.31; –0.17) and confirm the difficulty to perform selection simultaneously for both characteristics. UEM–3 and UEM–7 hybrids showed wide stability and high a posteriori averages for GY and PE. Both cultivars can be registered and recommended for cultivation in popcorn producing regions.

ABSTRACT Heirloom tomatoes are open-pollinated varieties bearing a wide diversity of colors and shapes that may be used by breeders aiming to improve physical and biochemical fruit traits. Hence, in this work heirloom tomato accessions were characterized, gathering information to genetic breeding programs focusing on human food. For that, 67 heirloom tomato accessions were evaluated for fruit size, fruit mass, fruit volume, color, vitamin C, titratable acidity, soluble solids content, phenolic compounds content, total flavonoid content, and antioxidant activity. The experiment was conducted in a randomized complete block design with three repetitions. Linear mixed model, Pearson’s correlation and hierarchical clustering were applied to data. Five groups were formed by Ward’s clustering method. The accession UEL 300 constituted group A, which had the greatest mass and volume fruit. Eight accessions formed group B and showed mostly yellow fruits. Group C was comprised of 13 accessions, which had the highest levels of carotenoids, vitamin C, and antioxidant activity. Thirty-three accessions that constituted group D did not stand out for any of the attributes, while 12 accessions into group E had the highest content of phenolic compounds and flavonoids, along with the highest ratio of soluble solids and acidity. Five accessions in this collection (UEL 296, UEL 146, UEL 238, UEL 231, and UEL 217) stood out for their biochemical traits. The wide diversity for physical and biochemical fruit traits can be explored in tomato breeding programs, seeking to develop new cultivars, and strengthening family farming.

Resumo O mirtilo é uma espécie de difícil enraizamento; sendo assim, alternativas que maximizem o potencial rizogênico de suas estacas são fundamentais para a expansão da cultura. O objetivo deste trabalho foi avaliar o efeito da lesão basal e diferentes métodos de aplicação de ácido indolbutírico (AIB) no enraizamento de estacas herbáceas de mirtilo ‘Woodard’, coletadas em duas épocas do ano. O delineamento experimental utilizado foi inteiramente casualizado, em arranjo fatorial 3x2x2, totalizando 12 tratamentos e cinco repetições. Os fatores consistiram em diferentes formas de aplicação de AIB (em talco e em álcool, na concentração de 1.000 mg L-1, e sem AIB), em épocas de coleta de estacas (outono e verão), e em dois tipos de estacas (com e sem lesão na porção basal). Após 200 dias do início do experimento, não foi observado efeito significativo da lesão basal no enraizamento das estacas. Porém, verificou-se que as estacas do mirtilo ‘Woodard’ são influenciadas pela época de coleta, com maior retenção foliar, massa seca, número de raízes por estaca, comprimento de raízes e comprimento da maior raiz, quando coletadas no verão. A aplicação de AIB em talco proporcionou maior porcentagem de estacas enraizadas (61,0%) em relação ao álcool (31,0%) e ao controle (41,0%), quando coletadas no outono. A aplicação em talco não diferiu entre as épocas, porém a aplicação em álcool e o controle resultaram em maiores porcentagens de estacas enraizadas no verão (70,0% e 67,0%, respectivamente). Conclui-se que o verão é a melhor época para a coleta de estacas de mirtilo ‘Woodard’, embora o AIB aplicado na forma de talco tenha aumentado a porcentagem de estacas enraizadas no outono. A lesão basal não promoveu incremento no enraizamento de estacas.

Abstract Blueberry cuttings are difficult to root, so alternatives that maximize their rhizogenic potential are essential for the expansion of the crop. The objective of this work was to evaluate the effect of the basal lesion and different methods of indolebutyric acid (IBA) on the rooting of ‘Woodard’ herbaceous cuttings, collected in two seasons. The experimental design used was completely randomized in a 3x2x2 factorial arrangement, totaling 12 treatments and five replications. The factors consisted of different ways of IBA application (talc and alcohol in the concentration of 1,000 mg L-1, and without IBA), season of collection (autumn and summer), and two types of cuttings (with and without lesion in the basal portion). Two hundred days after the beginning of the experiment, there was no significant effect of the basal lesion on the rooting of the cuttings. However, it was found that rooting is influenced by the season of collection, with greater leaf retention, dry weight, number of roots per cutting, length of roots and length of the largest root collected in summer. The application of IBA talc provided a higher percentage of rooted cuttings (61.0%) in relation to alcohol (31.0%) and control (41.0%) when collected in the autumn. There was no difference between seasons when IBA was applied with talc, however, the application with alcohol solution and the control resulted in higher percentages of rooted cuttings in the summer (70.0% and 67.0%, respectively). Summer was considered the best season to collect ‘Woodard’ blueberry cuttings, although the IBA applied with talc has increased the percentage of rooted cuttings in the autumn. The basal lesion did not promote an increase in rooting.

RESUMO O conhecimento da capacidade de combinação entre genótipos, diversidade genética e heterose desempenha um papel fundamental na obtenção de híbridos duplos com potencial produtivo. Este estudo teve como objetivo avaliar esses parâmetros em genótipos de tomate por meio de um cruzamento dialélico balanceado entre híbridos simples comerciais, gerando híbridos duplos. Os genótipos de tomate incluíram 15 híbridos duplos, seus genitores e dois genótipos comerciais como testemunhas. Dos 15 híbridos duplos, dois cruzamentos exibiram superioridade, Aguamiel × Compack e Dominador × Compack, principalmente em relação à produção de frutos comerciais. Para essa caracteristica, genes com efeito não aditivo controlam sua expressão. Para massa do fruto, diâmetro horizontal, diâmetro vertical e altura de inserção do cacho, genes com efeito aditivo são responsáveis pela sua expressão genotípica. Em relação à diversidade genética, as análises moleculares indicaram polimorfismo para 79% dos locos avaliados, evidenciando a alta variabilidade genética dos genitores. Os valores de heterose foram baixos para a maioria dos cruzamentos, exceto para a combinação Quarenta × Plutão, que apresentou heterose de 107% para a produção total de frutos. O cruzamento dialélico gerou combinações híbridas com desempenho superior em relação às testemunhas comerciais, sugerindo a possibilidade de obter híbridos duplos de tomate com heterose significante.

ABSTRACT Knowledge of the combining ability of genotypes, genetic diversity, and heterosis play the paramount role in obtaining double-cross hybrids with high productivity. This study was aimed at evaluating these parameters in tomato genotypes using partial diallel crosses among the commercial single-cross hybrids, which verified the possibility of using double-cross hybrids for commercial purposes. Tomato genotypes included 15 double-cross hybrids, their genitors, and two commercial genotypes as checks. Of the fifteen double-cross hybrids of tomato, two crosses exhibited superiority, such as Aguamiel × Compack and Dominador × Compack, mainly for the total and commercial fruit yields. The phenotypic expression of the trait is controlled by the genes with non-additive effects, whereas the genes with additive effects account for the genotypes of fruit mass, horizontal diameter, vertical diameter, and bunch insertion height. Regarding the genetic diversity, molecular analyses pointed out polymorphism for 79 percent of the evaluated loci evidencing a high genetic variability among the genitors. The heterosis values were low for most of the crosses, except for Forty × Plutão that represented 107 percent of heterosis for the total fruit yield. As compared with the commercial checks, the diallel cross generated superior quality hybrids, which inferred the possibility of obtaining double-cross hybrids of tomato with significant heterosis.

ABSTRACT Whiteflies (Bemisia tabaci) are a serious threat to tomato (Solanum lycopersicum) yield and production since all varieties are highly susceptible to this insect. The wild tomato Solanum pennellii shows resistance towards whiteflies infestation due the high contents of acylsugars presents in its leaflets, which is not observed in S. lycopersicum. Thus, plants from the F2BC2 population derived from the cross between the cultivar S. lycopersicum ‘Redenção’ and S. pennellii (accession LA-716) were selected for acylsugars levels and evaluated for resistance to whitefly and fumagine, a saprophyte fungus from genus Capnodium (sooty mold) that grows on leaves using whiteflies excretion. Biological behavior of B. tabaci was significantly influenced by the levels of acylsugars on the leaflets of the different genotypes. Solanum pennellii and the genotypes with higher acylsugars contents exhibited the lowest whitefly oviposition preference, number of nymphs, exuviae and adult survival. Also, the percentage of leaf coverage with fumagine was significantly reduced on leaves of the S. pennellii and the genotypes with higher acylsugars. Thus, it confirms that the use of S. pennellii LA-716 enabled the introgression of genes to increase the degrees of resistance in the F2BC2 genotypes. Finally, the results presented suggest that the genotypes RVTA-2010-31-177pl#39, RVTA-2010-31-319pl#214 and RVTA-2010-83-347pl#257 can be used as potential sources of genes for resistance to B. tabaci in tomato breeding programs.

ABSTRACT The evaluation of genetic diversity among the accessions of a germplasm collection results in information about promising materials suitable for breeding programs. Thus, the goal of this work was to characterize Capsicum baccatum accessions from different Brazilian regions, based on morphological, biochemical and molecular traits, aiming to support chili pepper breeding programs. The fruits were morphologically characterized based on fruit length, diameter, fresh mass and pericarp thickness, and biochemically analyzed for their content in ascorbic and phenolic acids, flavonoid and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and ferric reducing antioxidant power (FRAP) assays. All phenotypic traits showed significant differences among the chili pepper accessions, indicating a wide variability. The fruits were also characterized using amplified fragment length polymorphism (AFLP) molecular markers. The combination of six AFLP primers resulted in 1117 bands, 1033 of which were polymorphic. Divergence between accessions was estimated by the Ward’s hierarchical agglomerative clustering method, resulting in three and two clusters for fruit phenotypic traits and molecular data, respectively. In Bayesian analysis, molecular data also clustered the accessions in two groups. There was no association between the phenotypic descriptors and AFLP markers, indicating that both characterizations are important to better understand the genetic variability. Furthermore, it was not possible to group the accessions solely based on their origin for neither phenotypic descriptors and AFLP markers. The accessions G1, G5, G6, and G20 showed interesting characteristics and can be used in breeding programs, aiming the development of Capsicum spp. cultivars with desirable morphological and biochemical traits.

RESUMO A interação genótipo-ambiente (GA) é um complicador para a seleção de novos genótipos. A abordagem Bayesiana é uma ferramenta que pode aumentar a eficiência das metodologias de adaptabilidade e estabilidade. Nesse contexto, o objetivo deste estudo foi avaliar os parâmetros lineares e bi-lineares da análise AMMI (Additive Main Effects and Multiplicative Interaction) pela abordagem Bayesiana na seleção de genótipos de soja tipo alimento em ensaios multi-ambientes. A produtividade de grãos de cinco linhagens livres das enzimas lipoxigenases e destinadas ao consumo humano do Programa de Melhoramento de Soja da Universidade Estadual de Londrina e duas cultivares comerciais (BRS 257 e BMX Potência RR) foram avaliadas em quatro municípios do Estado do Paraná, nas safras 2014/15, 2015/16 e 2016/17. Das linhagens avaliadas, apenas a UEL 110 e UEL 122 tiveram efeitos genotípicos a posteriori positivos, superiores a 95% de confiabilidade a cultivar comercial BRS 257. Somente as linhagens UEL 115 e UEL 123 não contribuíram significativamente para a interação GA. As linhagens UEL 110 e UEL 122 foram adaptáveis ao maior número de ambientes de interação GA significativas e, portanto, são promissoras para o desenvolvimento de novas cultivares de soja tipo alimento. A utilização da AMMI1 (CP1 vs efeitos genotípicos) mostrou resultados para a estabilidade semelhantes ao AMMI2 (CP1 vs CP2), o que possibilitou uma seleção direta pelo biplot para produtividade e estabilidade.

ABSTRACT A complicating factor for the selection of plant strains is the influence of a genotype-environment (GE) interaction. The Bayesian approach is a tool to increase the efficiency of adaptability and stability methodologies. In this context, the objective of this study was to evaluate the linear and bi-linear parameters of the additive main effects and multiplicative interaction (AMMI) analysis using the Bayesian approach for selection of food-type soybean genotypes in multi-environment trials. The grain yields of five lipoxygenase-free lines intended for human consumption of from the soybean breeding program of the Londrina State University and two commercial standards (BRS 257 and BMX Potência RR) were evaluated in four counties of the State of Paraná, Brazil, in the 2014/15, 2015/16 and 2016/17 growing seasons. Of the evaluated lines, only UEL 110 and UEL 122 had positive posterior genotypic effects, exceeding a probability of 95% against the commercial standard BRS 257. Only lines UEL 115 and UEL 123 did not contribute significantly to the GE interaction. Lines UEL 110 and UEL 122 proved adaptable to the largest number of environments with significant GE interaction and are therefore promising for the development of new food-type soybean cultivars. The use of AMMI1 (PC1 vs. effects genotypes) showed results for the stability of genotypes similar to AMMI2 (PC1 vs PC2), allowing a direct selection by the biplot for productivity and stability.

ABSTRACT. The conservation of okra landraces [Abelmoschus esculentus (L.) Moench] in gene banks is essential for the success of their use in breeding programmes. This study evaluated the genetic diversity among okra landraces in Brazil based on morphoagronomic descriptors and AFLP markers. We studied 30 accessions of the vegetable gene bank of the Universidade Federal de Viçosa. To this end, 17 morphoagronomic descriptors and five combinations of AFLP primers were used. Genetic parameters were estimated for the quantitative traits and the accessions were grouped by Ward’s method, using the Gower’s and Jaccard’s distance measures, respectively, for the morphoagronomic and molecular data. Polymorphisms were observed for all qualitative traits, while the quantitative traits were significant by deviance analysis. The genetic parameters confirmed the existence of variability among accessions, and high accuracy and heritability indices were found for the traits related to fruit and plant height. Ward’s grouping showed no relationship between the clusters formed with the morphoagronomic and molecular data and the geographical origin of the accessions. No association between morphoagronomic descriptors and AFLP markers was observed. The lack of correlation suggests that both approaches of characterization are important to understand and differentiate the okra accessions.

ABSTRACT In the present study it is hypothesized that the germplasm of popcorn of tropical regions shows resistance to FAW, and the multivariate analysis can characterize the main traits of this resistance. Thus, the aim of this study was to identify key traits used to select fall armyworm resistance in popcorn by using factor and cluster analyses. Sixteen biological traits were evaluated at larval and pupae stages: total number of armyworm, time larval period, final mass of caterpillars, total mass of caterpillars, mean mass of caterpillars, pupae period, mass of pupae and some indices used to evaluate the food consumed by the caterpillars. Multicollinearity diagnosis, factor and canonical analysis, and the genetic divergence among the genotypes were performed to implement multivariate analysis. The groups were established according to Mojena (1977). After multicollinearity test, only five traits were retained for further analysis. The factor analysis divided the five traits into two factors: the first factor included time larval period, metabolized food and mass of pupae; the second was composed of total number of armyworm and stool mass. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) grouped the eighteen genotypes in three clusters. The present study provides insights of popcorn resistance to fall armyworm, and the multivariate analytical approach used here is directly applicable to any species and set of traits exhibiting correlation.

RESUMO A mamoneira (Ricinus communis L.) é uma oleaginosa encontrada em várias regiões do mundo, devido à sua fácil propagação e adaptação. O cultivo de genótipos mais produtivos, resistentes a doenças e que permitem o uso de mecanização traz maior retorno econômico para os produtores. Objetivou-se realizar a caracterização morfológica e seleção de acessos de mamoneira promissores para o cultivo mecanizado, sobretudo como fonte de variabilidade para programas de melhoramento com este propósito. Cinquenta acessos foram avaliados. Os dados foram submetidos a análise de variância, análise de agrupamento pelo método UPGMA e análise de componentes principais. A análise de dissimilaridade baseada na distância de Gower para variáveis qualitativas e quantitativas revelou três grupos de acessos e a análise de componentes principais possibilitou a seleção daqueles com características desejáveis. Os acessos BOC1, PRAT1 e SM2 exibiram características morfoagronômicas de interesse para o cultivo mecanizado, tais como altura de planta, diâmetro, peso de sementes e teor de óleo ideais. Tais genótipos mostram potencial para uso como genitores em programas de melhoramento genético de mamoneira.

ABSTRACT Castor bean (Ricinus communis L.) is an oilseed found in different regions worldwide, due to its easy propagation and adaptability. Cropping more productive disease-resistant genotypes that enable a mechanized production ensures greater economic returns for farmers. This study aimed to morphologically characterize and select promising castor bean accessions for mechanized cropping, mainly as a source of genetic variability for breeding programs with this purpose. Fifty accessions were assessed. Analysis of variance, dissimilarity clustering via the unweighted pair-group method with arithmetic mean (UPGMA) and principal component analysis were used to analyze the collected data. The dissimilarity analysis based on the Gower distance for qualitative and quantitative variables revealed three groups of accessions and the principal component analysis enabled the selection of those with desirable traits. The accessions BOC1, PRAT1 and SM2 exhibited morpho-agronomic characteristics of interest to the mechanized production, such as ideal plant height, diameter, seed weight and oil content. Such genotypes show a potential for use as genitors in genetic breeding programs of castor bean.

Resumo O feijão-vagem (Phaseolus vulgaris L.) é uma leguminosa economicamente importante em todo o mundo, devido à sua boa qualidade nutricional, considerada fonte de proteínas, fibras, vitaminas e minerais. Além disso, esta hortaliça apresenta altos níveis de compostos fenólicos e atividade antioxidante, fatores que contribuem para a prevenção contra os efeitos de oxidação por radicais livres. Assim, o presente estudo caracterizou cinco genótipos de feijão-vagem (UEL 1, UEL 2, UEL 405, UEL 415 e Alessa) em relação à concentração de aminoácidos, ao teor de compostos fenólicos totais e à atividade antioxidante. A análise de aminoácidos indicou que os genótipos UEL 415 e UEL 2 apresentaram as maiores concentrações de ácido glutâmico e histidina, com 12,9 e 2,27 g/ 100 g, respectivamente. No entanto, apenas o genótipo UEL 1 apresentou as maiores concentrações de compostos fenólicos totais (0,492 mg GAE / 100 g) e a capacidade antioxidante por captura de radicais DPPH• (64,71%). Os genótipos UEL 1, UEL 2 e UEL 415 apresentaram características desejáveis para o programa de melhoramento genético de feijão e exploração comercial por indústrias de alimentos.

Abstract The snap bean (Phaseolus vulgaris L.) is an economically important legume worldwide due to its good nutritional quality, being considered as a source of protein, fibre, vitamins and minerals. Furthermore, snap beans present high phenolic compound levels and antioxidant activity, factors that contribute in the prevention of the oxidation effects by free radicals. Hence, the present study characterized five snap bean genotypes (UEL 1, UEL 2, UEL 405, UEL 415 and Alessa) with respect to their amino acid concentrations, total phenolic compound contents and antioxidant activities. The amino acid analysis indicated that UEL 415 showed the highest glutamic acid content (12.9 g / 100 g) and UEL 2 the highest histidine content (2.27 g / 100 g). However, only the UEL 1 genotype showed the highest total phenolic compound content (0.492 mg GAE / 100 g) and highest antioxidant activity according to DPPH• radical scavenging (64.71%). The UEL 1, UEL 2 and UEL 415 genotypes presented desirable chemical characteristics for genetic improvement programmes and their commercial exploitation by food industries.

RESUMO O número de cultivares de milho doce adaptada às condições climáticas e com características agronômicas recomendadas para o mercado brasileiro ainda é restrito. Assim, objetivou-se investigar as capacidades de combinações gerais e específicas em relação ao rendimento de grãos (GY) e teor de sólidos solúveis totais (TSS) de sete linhagens de milho doce (su1) e oito linhagens de milho super-doce (sh2) pela análise de cruzamentos dialélicos. Para TSS, as linhagens SC6 e SC7 de milho doce, e SSC7 e SSC8 de milho super-doce apresentaram valores superiores para capacidade geral de combinação. Para rendimento de grãos, as linhagens SC1 e SC2 de milho doce, e SSC4 e SSC6 apresentaram valores superiores para capacidade geral de combinação. TSS em milho doce, os híbridos 4x6 e 1x7 apresentaram as estimativas Ŝijsuperiores em todos os ambientes avaliados. Para GY, o híbrido 5x7 foi o mais relevante pois apresentou amais alta estimativa Ŝij na grande maioria dos ambientes. Além disso, os híbridos 1x4, 3x4 e 1x7 destacaram-se com valores positivos em todos os ambientes. Em milho super-doce, os híbridos 2x8, 3x6 e 5x6 devem ser selecionados como os mais promissores para ambos os caracteres (TSS e GY), pois apresentaram estimativas Ŝij positivas e altas nos seis ambientes.

ABSTRACT The number of sweet corn cultivars adapted to the climatic conditions and with agronomic traits recommended to the Brazilian market is still limited. Thus, the aim was to investigate the general and specific combining ability (GCA and SCA, respectively) in relation to the grain yield (GY) and total soluble solid (TSS) contents of seven lines of sweet corn (su1) and eight lines of supersweet corn (sh2) by diallel crosses. For TSS, the inbred lines SC6 and SC7 of sweet corn, and SSC7 and SSC8 of supersweet corn showed higher GCA effect. For GY, the inbred lines SC1 and SC2 of sweet corn and SSC4 and SSC6 of supersweet corn showed higher GCA effect. For TSS in sweet corn, the hybrids '4 × 6' and '1 × 7' showed the superior Ŝij estimates across all evaluated environments. For GY, the hybrid '5 × 7' was the most relevant because it showed higher Ŝij estimates in most of the evaluated environments. Additionally, the hybrids '1 × 4', '3 × 4', and '1 × 7' showed positive Ŝij values across all environments. In supersweet corn, the hybrids '2 × 8', '3 × 6', and '5 × 6' should be selected as the most promising for both traits (TSS and GY), because they presented positive and high Ŝij estimates across the six environments.

ABSTRACT The Azospirillum is considered one of the most studied plant growth promoter genus. These bacteria are capable of promoting plant growth through several factors. However, the effect of Azospirillum spp. associated to nitrogen fertilization on maize grain yield has brought about controversial results. Thus, the objective of this study was to verify the influence of topdressing nitrogen on the effect of Azospirillum spp. inoculation on maize crops through meta-analysis. Data were collected from articles published in scientific journals, obtained from the Web of Science®, Scopus® and Google Scholar® databases. The bibliographic review included only articles with direct comparisons between maize yield in the presence and absence of Azospirillum spp. under field conditions in Brazil. The meta-analysis of the random effects was carried out using all entries. Subgroup and meta-regression analysis were realized to verify the influence of nitrogen fertilization on the explanation of the possible heterogeneity among effect measures. Maize inoculation with Azospirillum spp. showed an average yield increase of 651.58 kg·ha-1, considering all trials, and of 1034.28 kg·ha-1 considering only the trials without topdressing nitrogen. There was no significant increase in grain yield when inoculation with bacteria from the Azospirillum genus was realized together with nitrogen fertilization, indicating that such technologies are non-additive.