ABSTRACT Large amounts of nitrogen (N) fertilizers applied to maize cropping systems support high yields but cause adverse environmental impacts. The development of cultivars with higher N use efficiency is essential to maintain sustainable production. Thus, the present study aimed to select popcorn inbred lines efficient and responsive to N fertilization expressing high popping expansion. Fifty-one popcorn inbred lines from different origins were evaluated in the field under low and high N availability, arranged in a randomized complete block design with three replications. The two main traits of economic interest in the crop were evaluated: grain yield (GY) and popping expansion (PE). A joint analysis of variance was performed and a scatter plot was generated to classify the inbred lines regarding the response to the N use, focusing on GY. For PE, a Scott-Knott grouping of means was conducted. Within the panel of evaluated popcorn inbred lines, it was possible to identify sources of favorable alleles for nitrogen use efficiency and popcorn expansion, highlighting the inbred lines L205, L206, L217, and L395. These genotypes emerge as potential parents to be included in mating blocks for the development of hybrids and/or breeding populations with high nitrogen use efficiency and popping expansion.

Abstract The objective of this work was to select maize hybrids using the GGE biplot analysis, as well as to evaluate their stability and adaptability in different environments of the North and Midwest regions of Brazil. Thirty-six maize hybrids were evaluated in 2018, in the following five environments in the Northern and Midwestern regions, respectively: in the municipality of Vilhena, in the state of Rondônia; and in the municipalities of Sorriso, Sinop, Alta Floresta, and Carlinda, in the Northern region of the state of Mato Grosso. The experimental design was a randomized complete block design. The analysis of variance was performed, and adaptability and stability were estimated by the GGE biplot method based on grain yield performance. A significant interaction between genotypes and environments was detected, and the biplot analysis was efficient in explaining 62.74% of the total variation in the first two principal components, with the formation of three macroenvironments. The 1P2227, 'BRS 3042', and 1P2265 hybrids showed high yield, responsiveness, and stability in the evaluated environments. The DKB310VTPRO2 hybrid was the most unstable genotype. The recommended hybrids are: DKB310 for the Sorriso and Vilhena macroenvironment; 1M1810 and 1O2106 for the Carlinda environment; and 1M1807 for the Sinop environment.

Resumo O objetivo deste trabalho foi selecionar híbridos de milho, por meio da análise GGE biplot, bem como avaliar sua estabilidade e adaptabilidade em diferentes ambientes das regiões Centro-Oeste e Norte do Brasil. Trinta e seis híbridos de milho foram avaliados em 2018, nos seguintes cinco ambientes das regiões Norte e Centro-Oeste, respectivamente: no município de Vilhena, no estado de Rondônia; e nos municípios de Sorriso, Sinop, Alta Floresta e Carlinda, na região norte do estado de Mato Grosso. O delineamento experimental foi em blocos completos ao acaso. Realizou-se a análise de variância, e estimaramse a adaptabilidade e a estabilidade pelo método GGE biplot com base na produtividade. Detectou-se interação significativa entre genótipos e ambientes, e a análise biplot foi eficiente para explicar 62,74% da variação total nos dois primeiros componentes principais, com a formação de três macroambientes. Os híbridos 1P2227, 'BRS 3042' e 1P2265 apresentam alta produtividade, capacidade de resposta e estabilidade nos ambientes avaliados. O híbrido DKB310VTPRO2 foi o genótipo mais instável. Os híbridos recomendados são: DKB310 para o macroambiente Sorriso e Vilhena; 1M1810 e 1O2106 para o ambiente Carlinda; e 1M1807 para o ambiente Sinop.

Abstract The hybrids UENF N01, N02 and N03 have enhanced nitrogen-use efficiency, particularly in terms of N responsiveness, which makes them ideal for low-input cultivation. Even under abiotic stress, popping expansion is not reduced, indicating these hybrids for growth in the N and NW of Rio de Janeiro State. N01 N0 nitrogenuse nitrogen use efficiency responsiveness lowinput low input cultivation stress reduced State

Abstract The hybrids are responsive to phosphorus application, have high use efficiency and can produce high mean yields in environments with low and high phosphorus. The mean PE of these hybrids is high, therefore they are recommended for cultivation in the North and Northwest regions of Rio de Janeiro State, Brazil. application State Brazil

ABSTRACT Ear rot caused by fungi of genus Fusarium (FER) is one of the potentially harmful diseases to grain quality in maize. Given the capacity to produce mycotoxins, FER presents a risk to food safety. This study sought to identify parents and indicate hybrids of popcorn with a higher level of resistance to the incidence and severity of FER. Hybrids were produced from the crossing of 15 lines in S7 generation and 5 testers. The hybrids, together with the parents and five more genotypes used as control, were evaluated in a field trial. It was used a randomized block design arranged in 10 x 10 lattice. Data were submitted to analysis of variance by the F test (p < 0.05) and then by the mean grouping test of Scott Knott (p < 0.05). The results showed the possible to explore new sources of resistance to FER among germplasm evaluated. Both additive and non-additive gene effects are important in FER resistance. To obtain gains in FER resistance, the development of popcorn hybrids should consider the use of parental lines with low means of severity and good general combining ability.

ABSTRACT The objective of this study was to conduct a meta-analysis and test its efficiency in summarizing the heterogeneous data of heritability estimates for the traits of grain yield (GY) and popping expansion (PE), and to provide reliable estimates of selection gains in popcorn. Therefore, 97 heritability estimates (ĥ 2) for popcorn GY and PE in the broad and narrow sense were used. The main procedures underlying the estimation of the combined heritability (ĥ 2 + ) using the technique of meta-analysis consisted of i) an exploratory analysis of the set of heritability estimates to detect outliers using a box-plot chart, ii) the verification of the required statistical assumptions, iii) testing the involved heritability estimates for homogeneity, and iv) the calculation of the estimates of combined heritability. The meta-analysis facilitated the synthesis of the information pertaining to heritability in popcorn. The combined heritability estimates (ĥ 2 + ) in the broad sense for GY and PE were 0.5208 ± 0.0229 and 0.6356 ± 0.0209, respectively, and in the narrow sense were 0.3290 ± 0.0292 and 0.3083 ± 0.0298, respectively.

ABSTRACT: Multicollinearity is a very common problem in studies that employ path analysis in agronomic crops, which generates unrealistic results and erroneous interpretations. This study was aimed at assessing the path analysis in data obtained from guava tree full-sib based on modelling multiple regressions applying latent variables to neutralize the effects of multicollinearity. Seven explanatory variables were measured – fruit mass (FM), fruit length (FL), fruit diameter (FD), mesocarp thickness (MT), peel thickness (PT), pulp mass (PM), total number of fruits (NTF) –, plus the main dependent variable, total yield per plant (YIELD). In accordance with the multicollinearity scenario, eleven values were tested with the addition of the constant K to the diagonal of the correlation matrix X’X. Path analysis was applied in two models: all the explanatory variables with direct effect on the dependent one and another model with multiple regression with more than one chain and the presence of latent variables. The path analysis in the multivariate methodology of structural equation modelling (SEM), which uses latent variable prediction, provided better results than the traditional and ridge path analyses.

Abstract The UENF WS01 is a hybrid that has an early cycle and high grain yield capacity under low water and nitrogen availability. It maintains popping expansion even under abiotic stress, thus being recommended for cultivation in the North and Northwest of the State of Rio de Janeiro.

ABSTRACT. Our objectives were to evaluate general and specific combining ability (SCA) and genetic divergence among tropical maize inbred lines using single sequence repeat (SSR) markers. Thirteen inbred lines were crossed based on a complete diallel scheme. Hybrids and three checks were evaluated in a lattice experimental design. Silk and anthesis flowering, average plant height, average ear height, white spot (Pantoea ananatis) and gray leaf spot (Cercospora zeae-maydis) severity, and grain yield were evaluated. Significant differences (p < 0.05) for general and specific combining abilities were observed for all traits. Based on additive effects, inbred lines 1 (Flash) and 12 (SG 6015) were selected to reduce the flowering period and plant and ear height. Inbred lines 2 (CD 303) and 3 (AG 8080) were selected to reduce disease severity. For the simultaneous increase in grain yield and reduced severity of diseases, line 11 (AG 9090) as a parent or tester in topcross schemes is recommended. According to non-additive effects, crosses 2 (CD 303) × 13 (DKB 747) and 11 (AG 9090) × 12 (SG 6015) were selected for grain yield and future breeding programs. Six groups were identified using SSR markers; a major group contained six inbred lines. Because of the minor relationship between genetic divergence and SCA effects on grain yield limits, the use of the groups for future divergent crosses is recommended.

RESUMO: A expressão potencial da produtividade das culturas constitui um desafio constante aos criadores de plantas frente às oscilações das variáveis ambientais, dificultando a seleção e onerando os custos operacionais e metodológicos na obtenção da cultivar ideal para determinada região. O objetivo do trabalho foi investigar os efeitos da interação genótipos x ambientes na seleção de linhagens de feijão-caupi com alta produtividade de grãos, adaptabilidade e estabilidade genotípica simultaneamente, em ambientes da região Noroeste do estado do Rio de Janeiro, usando modelos mistos (Máximo Verosimilhança Restrita - REML/Melhor Predição Linear não Viesado - BLUP). Avaliou-se 27 genótipos de feijão-caupi em seis ambientes pela combinação de local (Cambuci-RJ e Bom Jesus do Itabapoana-RJ) e ano (2016, 2017 e 2018). Foi utilizado o delineamento em blocos casualizados com quatro repetições. Os parâmetros genéticos foram estimados via procedimento REML/BLUP, e a seleção baseou-se no método da média harmônica do desempenho relativo dos valores genéticos (HMRPGV). Observou-se diferença significativa para ambiente e interação genótipo x ambiente. A variância residual e a variância da interação genótipo x ambiente formaram as maiores frações da variância fenotípica. As linhagens 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-ouro 1-5-4), 5 (Pingo-de-ouro 1-5-26) e 9 (Pingo-de-ouro 1-5-8) foram classificadas como superiores quanto a estabilidade e adaptabilidade e rendimento de grãos pelo critério da HMRPGV. As cultivares comerciais 13 (BRS-Tumucumaque) e 26 (BRS-Itaim) reuniram elevada produtividade de grãos, adaptabilidade e estabilidade específica nas condições edafoclimáticas avaliadas.

ABSTRACT: The potential expression of crop productivity is a constant challenge for plant breeders in the face of oscillations in environmental variables, making selection difficult and increasing the operational and methodological costs in obtaining the ideal cultivar for a determined region. The objective of the research was to investigate the effects of genotype x environment interaction in the selection of cowpea lines with high grain yield, adaptability, and genotypic stability simultaneously, in environments of the Northwest region of Rio de Janeiro State, using mixed models (Maximum Restricted Likelihood - REML/Best Linear Unbiased Prediction - BLUP). 27 cowpea genotypes were evaluated in six environments by combining location (Cambuci-RJ and Bom Jesus do Itabapoana-RJ) and year (2016, 2017 and 2018). A randomized block design with four replications was performed. The genetic parameters were estimated via the REML/BLUP procedure, and the selection was based on the harmonic mean method of the relative performance of the genetic values (HMRPGV). A meaningful difference was observed for environment and genotype x environment interaction. The residual variance and the variance of the genotype x environment interaction formed the most significant fractions of the phenotypic variance. Lines 4 (Bico-de-ouro 1-5-24), 6 (Pingo-de-Ouro 1-5-4), 5 (Pingo-de-Ouro 1-5-26), and 9 (Pingo-de-Ouro 1-5-8), stood out as superior in terms of stability and adaptability and grain yield by HMRPGV. Commercial cultivars 13 (BRS-Tumucumaque) and 26 (BRS-Itaim) had high grain yield, adaptability, and specific stability in the evaluated edaphoclimatic conditions.

ABSTRACT The objective of this study was to estimate the varietal and heterotic effects related to grain yield, popping expansion and resistance of popcorn against fall armyworm. Twelve open-pollinated varieties were intercrossed in a complete diallel mating scheme. The 66 experimental hybrids, together with their parents and controls Zapalote Chico, BRS 1030 and IAC 125, resulted in a total of 81 treatments, evaluated in an experiment in a 9x9 triple-square lattice design, in Maringá-PR and Araruna-PR. The data were analyzed according to the diallel model of Gardner and Eberhart (1966). The following traits were evaluated: grain yield (GR); mean plant height (PH) and insertion height of the highest ear in the stem (EI); silking (SIL); final plant density (FD) and popping expansion (PE). Variety PR 023 is indicated for intrapopulation improvement for grain yield. Regarding popping expansion, the results indicated cross SAM x UNB 2U C5 for recurrent reciprocal selection. In relation to resistance to fall armyworm, the varieties PARA 172, PA 091, PR 023, and SE 013 were selected for intrapopulation improvement. On the other hand, the crosses PARA 172 x BOZM 260, PA 091 x BOYA 462 and SAM x UNB 2U C5 can be indicated for interpopulation improvement.

Resumo: O objetivo deste trabalho foi avaliar as influências dos fatores genótipos de milho (Zea mays), safras agrícolas, texturas dos endospermas, fundo genético e bases genéticas nas taxas de haploides putativos (THPs), conforme a expressão do gene R1-navajo (R1-nj). Foram avaliados 41 genótipos de milho como receptores de pólen, em cruzamentos com o indutor “Krasnodar haploid inducer”, em duas safras (verão e inverno), no município de Maringá, no estado do Paraná, Brasil. O delineamento experimental foi o inteiramente casualizado com dez repetições (espigas). A variável resposta analisada foi a THP determinada pela proporção de haploides putativos, obtidos com base no marcador R1-nj, em relação ao número de sementes diploides por espiga. Posteriormente, foram utilizados modelos lineares generalizados para escolher o mais adequado para explicar a THP em função dos fatores testados. As safras, os genótipos e a interação safras x genótipos afetaram significativamente a THP, o que evidencia a dependência destes fatores na expressão do marcador fenotípico baseado na pigmentação por antocianina e determinado pelo gene dominante R1-nj. O número de agrupamentos formados pelos genótipos foram diferentes em cada safra. Dez genótipos apresentaram taxas maiores no verão do que no inverno. As texturas dos endospermas, as bases genéticas e o fundo genético não interferiram na THP.

Abstract: The objective of this work was to evaluate the influences of the factors corn (Zea mays) genotypes, crop seasons, endosperm texture, genetic background, and genetic basis on putative haploid rates (PHRs) according to the expression of gene R1-navajo (R1-nj). Forty-one corn genotypes were evaluated as pollen receptors, in crosses with the Krasnodar haploid inducer, in two crops (summer and winter), in the municipality of Maringá, in the state of Paraná, Brazil. The experimental design was completely randomized with ten replicates (ears). The response variable analyzed was the PHR, determined by the proportion of putative haploids, obtained through the R1-nj marker, in relation to the number of diploid seeds in each ear. Subsequently, generalized linear models were used to choose the one best fit to explain the PHR in function of the tested factors. Crop seasons, genotypes, and the crop seasons x genotypes interaction affected significantly the PHR, showing the dependence of these factors on the expression of the phenotypic marker based on anthocyanin pigmentation and determined by gene R1-nj. The number of clusters formed by the genotypes was different in each crop season. Ten genotypes showed higher rates in summer than in winter. Endosperm texture, genetic basis, and genetic background did not affect the PHR.

Abstract The major hindrance to guava fruit (Psidium guajava L.) growing is the low availability of cultivars for use by Brazilian producers, who usually rely on few options of genotypes to implement the crop. In the present study, 11 full-sib families were evaluated in a randomized-block experimental design with three replicates, in order to more efficiently select superior genotypes. Genetic parameters were estimated and the best genotypes were selected based on genetic value by applying the REML/BLUP statistical procedure. Additionally, genetic divergence was estimated based on the mean Euclidian distance between the individuals selected via BLUP. Based on genetic divergence, the best genotypes were selected for use as parents in new crosses aiming at continuity of the guava breeding program. The mean values of the traits of selected individuals surpassed the mean values of their parents, confirming that the strategy of obtaining full-sib families is effective in generating considerable gains.

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.

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 A ocorrência da correlação negativa entre produtividade de grãos (PG) e capacidade de expansão (CE) no milho-pipoca contribui para dificultar o processo seletivo. No intento de contornar esse inconveniente, foi proposto, o caráter de importância, volume por pipoca expandida por hectare (VP). O objetivo deste estudo foi desenvolver o nono ciclo da população UENF-14 de milho-pipoca, estimar o efeito direto e indireto de VP e averiguar o progresso genéticos entre todos os ciclos seletivos. Duzentas progênies endogâmicas foram obtidas e avaliadas em blocos casualizados, com arranjos em repetições dentro de sets, sendo nove sets, oito constituídos por 25 progênies e um set com todos ciclos anteriores (oito) com três repetições. Avaliou-se a altura média da planta, prolificidade, peso de cem grãos, produtividade de grãos, capacidade de expansão e volume por pipoca expandida por hectare. Realizou-se a análise de trilha para desdobrar os efeitos diretos e indiretos e o índice de seleção Mulamba e Mock para seleção de quarenta progênies superiores. Houve variabilidade genética entre as progênies para todas características. Existe relação de causa e efeito entre o VP com a PG e CE, permitindo ganhos simultâneos com a seleção indireta. A seleção das progênies superiores com a utilização do peso atribuído por alternativas proporcionou maiores ganhos preditos de VP (20,73%). As médias obtidas em todos os ciclos indicaram aumentos, demonstrando a eficiência do uso da seleção recorrente em programas de melhoramento de milho-pipoca.

ABSTRACT The occurrence of negative correlations between grain yield (GY) and popping expansion (PE) in popcorn complicates the selection process. In an attempt to overcome this inconvenience, we proposed the use of the importance characteristic volume per popcorn per hectare (PV). The objectives of this study were to develop the ninth cycle of the UENF-14 popcorn population, to estimate the direct and indirect effects of PV and to verify the genetic progress among all selective cycles. We obtained and evaluated 200 inbred progenies in randomised blocks arranged in replicates within sets, with nine sets consisting of 25 progenies and one set with all previous eight cycles with three replicates. The average height of the plants, prolificacy, 100-grain weight, grain yield, grain popping expansion and volume per popcorn per hectare were evaluated. Track analysis was performed to determine the direct and indirect effects, and the Mulamba and Mock selection index was calculated for the selection of the 40 superior progenies. There was genetic variability among progenies in all evaluated traits, with a cause-and-effect relationship between PV with GY and PE, allowing simultaneous gains with indirect selection. The selection of the best progenies was more effective when using arbitrarily assigned weights, which provided higher predicted gains for PV (20.73%). The means obtained in all cycles indicated increases, demonstrating the efficiency of using continuous recurrent selection in popcorn breeding programs.