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 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.

Resumo: O objetivo do trabalho foi avaliar a germinação e vigor das sementes de milho submetidas a diferentes produtos e períodos de armazenamento. O delineamento experimental foi inteiramente casualizado em esquema de parcelas subdivididas no tempo. Na parcela foram distribuídos nove tratamentos: uma testemunha não tratada, um tratamento denominado de “tratamento padrão”, com adição de fungicida (fludioxonil + metalaxyl-M) e inseticida (thiamethoxam). A partir do tratamento padrão, seis tratamentos com combinações de inoculante (Azospirillum brasilense), micronutrientes (nitrogen + potassium + zinc + boron + copper + iron + manganese + molibdenium) e biorregulador. Por fim, um tratamento denominado de “tratamento completo”, incluindo todos os produtos. Na subparcela, os períodos de armazenamento 0, 15, 30, 45, 60 e 90 dias foram avaliados. O vigor das sementes de milho foi reduzido pelos tratamentos de sementes e pelo armazenamento. A adição de micronutrientes resultou em maior fitotoxicidade em comparação à adição de outros produtos, independente do período de armazenamento. O uso de fungicida, inseticida e inoculante se mostram viáveis, como os mais promissores tratamentos de sementes. Nenhum dos tratamentos estudados afetaram a germinação até 45 dias de armazenamento, porém o tratamento completo, com 3200 mL. 100 kg-1 reduziu o vigor de sementes.

Abstract: The aim of the study was to evaluate seed germination and vigor of maize subjected to different products and storage periods. The experimental design was completely randomized in a split plot on time. In the plots were distributed nine treatments: an untreated control, one treatment called “standard treatment”, with addition of fungicide (fludioxonil + metalaxyl-M) and insecticide (thiamethoxam). From the standard treatment, six treatments with combinations of inoculant (Azospirillum brasilense), micronutrients (nitrogen + potassium + zinc + boron + copper + iron + manganese + molibdenium) and bioregulator. Lastly, a treatment called “complete treatment” including all products. In subplots the storage periods of zero, 15, 30, 45, 60 and 90 days were evaluated. Seed vigour of maize was reduced by seed treatments and storage. Micronutrients addition resulted in higher fitotoxicity in comparison to the addition of other products, regardless of storage period. The treatment with the combination of fungicide, insecticide and inoculant proved to be feasible, and was the most promising seed treatments. None of the studied treatments affected the germination in up to 45 days of storage, however the complete treatment with 3200 mL .100 kg-1 reduced seed vigour.

RESUMO: O objetivo do estudo foi avaliar genótipos de milho pipoca para resistência à lagarta-do-cartucho, Spodoptera frugiperda. O experimento foi conduzido em delineamento inteiramente casualizado com 30 repetições. Foram avaliados os genótipos de milho pipoca Aelton, Arzm 05 083, Beija-Flor, Colombiana, Composto Chico, Composto Gaúcha, Márcia, Mateus, Ufvm Barão Viçosa, Vanin, Viviane e Zapalote Chico. Larvas recém-eclodidas foram individualizadas para avaliação do desenvolvimento biológico e consumo alimentar. Os dados foram submetidos à análise multivariada de variância e a divergência genética entre genótipos foi avaliada através dos métodos de agrupamento de Tocher, com base na distância generalizada de Mahalanobis e análise de variáveis canônicas. Sete genótipos,Aelton, Arzm 05 083, Composto Chico, CompostoGaúcha, Márcia, Mateus e Viviane formaram um cluster (cluster I) que apresentaram antibiose com o mecanismo de resistência à praga. Os genótipos do cluster I e Zapalote Chico podem ser usados para empilhar genes para resistência por antibiose e não-preferência.

ABSTRACT: The aim of this study was to evaluate popcorn genotypes for resistance to the fall armyworm, Spodoptera frugiperda. The experiment used a completely randomized design with 30 replicates. The popcorn genotypes Aelton, Arzm 05 083, Beija-Flor, Colombiana, Composto Chico, Composto Gaúcha, Márcia, Mateus, Ufvm Barão Viçosa, Vanin, and Viviane were evaluated,along with the common maize variety Zapalote Chico. Newly hatched fall armyworm larvae were individually assessed with regard to biological development and consumption of food. The data were subjected to multivariate analyses of variance and genetic divergence among genotypes was evaluated through the clustering methods of Tocher based on generalized Mahalanobis distances and canonical variable analyses. Seven popcorn genotypes, namely, Aelton, Arzm 05 083, Composto Chico, Composto Gaúcha, Márcia, Mateus, and Viviane,were shown to form a cluster (cluster I) that had antibiosis as the mechanism of resistance to the pest. Cluster I genotypes and the Zapalote Chico genotype could be used for stacking genes for antibiosis and non-preference resistance.