Minimizing inter-genotypic competition effects to predict genetic values and selection in forestry genetic tests

The effect of competition is an important source of variation in breeding experiments. This study aimed to compare the selection of plants of open-pollinated families of Eucalyptus with and without the use of competition covariables. Genetic values were determined for each family and tree and for the traits height, diameter at breast height and timber volume in a randomized block design, resulting in the variance components, genetic parameters, selection gains, effective size and selection coincidence, with and without the use of covariables. Intergenotypic competition is an important factor of environmental variation. The use of competition covariables generally reduces the estimates of variance components and influences genetic gains in the studied traits. Intergenotypic competition biases the selection of open-pollinated eucalypt progenies, and can result in an erroneous choice of superior genotypes; the inclusion of covariables in the model reduces this influence

Prediction of genetic gains in sweet potato genotypes by polycross

Sweet potato crops present a wide genetic diversity, but genetic parameters of populations should be estimated in breeding programs, mainly when the selection is focused on multiple traits. Thus, the objective of this study was to estimate genetic parameters and select clones via a selection index in a sweet potato population obtained from uncontrolled crosses. The experiment was carried out in Ilha Solteira, Sao Paulo, Brazil, from June to November 2020, to evaluate 144 clones and three controls, totaling 147 treatments. A randomized block design was used, with two replications and three plants per plot. The data were analyzed through mixed modeling (REML/BLUP), and the selection index proposed by Mulamba & Mock was applied using a selection pressure of 17.3% for the selection of superior clones. The direct selection enabled a higher prediction of gains for each trait, but the joint analysis maximized the selection gains for all traits of interest. Clones 38, 63, 79, 77, and 5 are recommended, among the selected clones, for further stages of sweet potato breeding focused on improving traits for production and table consumption.   Keywords: Genetic parameters, Genetic variability, Ipomoea batatas (L.) Lam, Selection gain, Selection indexSweet potato crops present a wide genetic diversity, but genetic parameters of populations should be estimated in breeding programs, mainly when the selection is focused on multiple traits. Thus, the objective of this study was to estimate genetic parameters and select clones via a selection index in a sweet potato population obtained from uncontrolled crosses. The experiment was carried out in Ilha Solteira, Sao Paulo, Brazil, from June to November 2020, to evaluate 144 clones and three controls, totaling 147 treatments. A randomized block design was used, with two replications and three plants per plot. The data were analyzed through mixed modeling (REML/BLUP), and the selection index proposed by Mulamba & Mock was applied using a selection pressure of 17.3% for the selection of superior clones. The direct selection enabled a higher prediction of gains for each trait, but the joint analysis maximized the selection gains for all traits of interest. Clones 38, 63, 79, 77, and 5 are recommended, among the selected clones, for further stages of sweet potato breeding focused on improving traits for production and table consumption.   Palavras-chave: Ipomoea batatas (L.) Lam, Variabilidade genética, Índice de seleção, Parâmetros genéticos, Ganho com seleçã

Neighborhood analysis in evaluation of sugarcane genotypes

O objetivo deste trabalho foi estudar diferentes covariáveis de competição em análises de vizinhança, e verificar sua eficiência no aumento da precisão experimental e as consequências no ordenamento de genótipos de cana-de-açúcar em termos de potencial produtivo. Foram utilizados dados da rede de ensaios do programa de melhoramento de cana-de-açúcar do Instituto Agronômico, instalados em 2002. O delineamento foi em blocos ao acaso, com três repetições. As parcelas constituíram-se de cinco sulcos de 8 m, espaçados 1,50 m entre si. A produtividade de colmos por hectare (TCH, Mg ha-1) foi avaliada no primeiro e terceiro cortes. As covariáveis "lateral", "ponta" e "quatro vizinhos" foram incluídas nos métodos de Papadakis, em duas variações do método médias móveis. Os métodos de Papadakis e médias móveis 1 não alteraram a precisão experimental em comparação à análise tradicional. O método médias móveis 2 reduziu a variância ambiental, mas alterou as estimativas da variância genotípica e o ordenamento dos genótipos, o que pode induzir a conclusões equivocadas na seleção. Embora a covariável "lateral" tenha sido influente na competição, o efeito em parcelas de cinco sulcos é pequeno.The objective of this work was to study different competition covariates in neighborhood analysis and to check the efficiency of this analysis in the increase of the experimental precision and the consequences in the ranking of sugarcane genotypes in terms of productive potential. Data used were from the state experimental network of the sugarcane breeding program installed in 2002, of the Instituto Agronômico, Campinas, SP, Brazil. The experimental design was in randomized complete blocks, with three replicates. The plots were formed of five 8 m rows with 1.5-m spacing between rows. The stalk productivity (TCH, Mg ha-1) was evaluated in the first and third harvests. The covariates "side", "tip" and "4 neighbors" were included in the Papadakis method and in two variations of the moving average method. The Papadakis and moving average 1 methods did not change the experimental precision in comparison with traditional analysis. The moving average 2 method reduced the environmental variance. However, it changed the estimates of the genetic variance and the genotype ranking, and could lead to erroneous conclusions in the selection. Although the "side" covariate was influential on competition, its effect or on five row-plots was small

EVALUATION OF COMPETITION EFFECT IN Eucalyptus PROGENY TESTS

Muitos estudos t\ueam recomendado o uso de parcelas pequenas na experimenta\ue7\ue3o florestal, por\ue9m, n\ue3o consideram o aumento da competi\ue7\ue3o intergenot\uedpica que isto acarreta e que pode resultar na sele\ue7\ue3o incorreta dos materiais gen \ue9ticos. O objetivo deste trabalho foi o de avaliar sete covari\ue1veis de competi\ue7\ue3o sobre o car\ue1ter volume de madeira em dois testes de prog \ueanies de Eucalyptus spp. O delineamento utilizado foi de blocos casualizados, com seis repeti\ue7\uf5es de 10 plantas. As sete covari\ue1veis analisadas foram \uedndice de competi\ue7\ue3o de Hegyi (IC), autocompeti\ue7\ue3o (AT), alocompeti\ue7\ue3o (AL), m\ue9dia da autocompeti\ue7\ue3o (MAT), m\ue9dia da alocompeti\ue7\ue3o (MAL) e m\ue9dia aritm \ue9tica dos quatro (M4) e oito vizinhos mais pr\uf3ximos (M8). Essas covari\ue1veis foram avaliadas individualmente bem com em todas as suas poss \uedveis combina\ue7\uf5es, obtendo-se estimativas de componentes de vari \ue2ncias e suas altera\ue7\uf5es com o emprego das mesmas. A competi\ue7\ue3o influenciou os resultados de an\ue1lises de testes de prog \ueanies de eucalipto, em que, autocompeti\ue7\ue3o e alocompeti\ue7\ue3o interferem de forma diferenciada. As covari\ue1veis mais influentes s\ue3o a MAT, a MAL e o IC. A rotina de an\ue1lise que apresentou melhores resultados foi a que incluiu as covari\ue1veis IC/MAT, sendo eficiente na redu\ue7\ue3o do efeito competicional em testes de prog \ueanies de eucalipto.Many studies have recommended the use of small plots for forest experiments, although they do not consider the inter-genotype competition increase. If this competition is not isolated from the mathematics model, it can lead to incorrect selection of genetic materials. The aim of this work was to evaluate the effect of seven competition covariates in two Eucalyptus spp. progeny tests. Data from the two half-sib eucalyptus progenies were analyzed, using the randomized blocks design. The seven analyzed covariates were HegyI\u2019s competition index (IC), self-competition (AT), alo competition (AL), self-competition mean (MAT), alo competition mean (MAL), and arithmetic means of four (M4) and eight (M8) nearest neighbors. Individual and combined analyses of covariates were used for the wood volume trait. All the variance components and the changes caused by covariates use were evaluated. The competition affects the results of eucalypt progeny analysis in different ways, according to its type, self or alo competition. Most influential covariates were MAT, MAL and IC. Most promising results of competition effects reduction were observed for the IC/ MAT covariates inclusion in eucalypt progeny tests

Época de semeadura x grupos de maturação nos componentes de rendimentos de soja

A época de semeadura e o cultivar adaptada a cada região são fatores importantes para se obter a máxima produtividade de soja. Conhecer quais caracteres influenciam, de forma direta ou indireta, para a obtenção da maior produtividade, torna-se viável e por isso objetivou-se avaliar o efeito da época de semeadura em três cultivares com grupos de maturação (Semiprecoce, Médio e Semiprecoce, respectivamente) e de soja na região de Francisco Santos - PI. O experimento foi conduzido na fazenda Joaquim Isac na cidade de Francisco Santos Piauí, localização geográfica 6º 59 34 S 41º 8 16 W; 270 m de altitude. O delineamento experimental foi instalado em blocos casualizados com quatro repetições em esquema fatorial 4x3, totalizando 12 tratamentos. O primeiro fator constituiu de quatro épocas de semeadura: 30/12/2015, 06, 13, e 20 /01/2016. O segundo por três cultivares com grupos de maturação 8,2, 8,6 e 8,3. Observou-se efeito significativo da interação (CxE) para a maioria dos caracteres, exceto para a variável peso de mil grãos. Os elementos climáticos nas quatro épocas de semeadura na safra 2015/16 afetaram diretamente o desenvolvimento e produtividade da soja, sendo a segunda época a mais adequada; o cultivar 2 apresentou-se melhor que as demais e os caracteres número de grãos por planta e massa seca de caule produziram causa e efeito na produtividade de grãos em soja podendo ser recomendado na seleção direta com a produtividade

Esterase activity in homogenates of Helicoverpa armigera (Hubner) (Lepidoptera: noctuidae) exposed to different insecticides and the behavioral effect

The toxicity of some insecticides to Helicoverpa armigera was studied through sublethal effects, evaluating the enzymatic activity of esterase and the behavioral response. The commercial formulation of insecticides selected were chlorpyrifos, spinosad, indoxacarb, chlorantraniliprole, lambda-cyhalothrin and Bacillus thuringiensis, corresponding the most used by farmers to control of H. armigera. To determine the esterase activity, the larvae were fed with soybean leaf discs dipped in insecticide solution using the lethal concentration (LC50). For the behavioral response, filter paper were immersed in three concentrations of insecticides (LC50, LC95 and recommend dose.), then the behavior of the larvae observed in Videomex-One. The results for the enzymatic activity showed an increase in the activity of the esterase, with variation along the treatments and the time of exposure of the insects to the insecticides. With exception of spinosad, other insecticides showed an increase in EST-α activity, 6 and 24 hours after contact of caterpillars with insecticide.Different behavioral patterns of walking (walking distance, walking speed and resting time) were observed for H. armigera exposed to different insecticides. H. armigera exposed to chlorpyrifos, lambda-cyhalothrin and B. thuringiensis insecticides show greater esterase activity. Regarding walking behavior, the results confirms enzymatic activity, where H. armigera have behavioral alteration after exposure to insecticide

GERMINAÇÃO E CRESCIMENTO INICIAL DE PLÂNTULAS DE ESPÉCIES DE DIFERENTES PROCEDÊNCIAS DO GÊNERO Schizolobium spp.

Este trabalho foi realizado com o objetivo de avaliar o efeito das diferentes espécies e procedências do gênero Schizolobium na germinação das sementes e crescimento inicial das plântulas. Foram avaliadas duas espécies, sendo elas o S. parahyba e o S. amazonicum, onde as procedências da primeira foram de Ribeirão Grande – SP e Jaboticabal – SP e as da segunda foram de Belém – PA e Dom Elizeu – PA, estado do Acre e Mato Grosso. O delineamento utilizado foi inteiramente casualizado com 4 repetições e 25 sementes por parcela experimental. Foram avaliados no trabalho a porcentagem de germinação, o índice de velocidade de germinação, o índice de velocidade de emergência, porcentagem de sobrevivência, o comprimento da radícula e o comprimento da parte aérea da plântula. A procedência do Acre mostrou-se inferior às demais, em que se pressupõe que a mesma apresente menor potencial para plantio comercial. Das procedências apresentadas, a originada do estado de Mato Grosso foi a que apresentou os melhores resultados

Toxicity of Anadenanthera macrocarpa (Fabaceae: Mimosoideae) and Bougainvillea buttiana (Nyctaginaceae) extracts to lepidopteran pests

For small and medium agricultural production, vegetal extracts are highly efficient at managing pests because they control a wide range of arthropods. The objective of this research was to evaluate the toxic effects of Anadenanthera macrocarpa (Fabaceae: Mimosoideae) and Bougainvillea buttiana (Nyctaginaceae) extracts on Helicoverpa armigera (Hübner), Spodoptera cosmioides (Walker) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Helicoverpa armigera and S. cosmioides caterpillars were maintained on soybean leaf discs, and S. frugiperda was maintained on corn leaf discs, treated with diluted aqueous extracts at concentrations of 0, 500, 1,000, 2,500, 4,000, 5,000, 10,000 and 15,000 mg.L-1. The lethal and sublethal effects of the extracts on the insects were measured. According to the results, the concentration of 500 mg.L-1 of the A. macrocarpa extract caused the highest percentage of mortality (93.33%) of H. armigera. The extract of B. buttiana caused 86.67% and 60% mortality of H. armigera (1,000 mg.L-1) and S. cosmioides (4,000 mg.L-1), respectively. The reduction of the emergence of adults was the main sublethal effect found for S. cosmioides and S. frugiperda. Considering the results, the vegetal extracts used in this research are a potential alternative for the management of lepidopteran pests