Reciprocal recurrent selection for obtaining water-deficit tolerant maize progeny / Seleção recorrente recíproca para obtenção de progênies de milho tolerantes ao déficit hídrico

In view of the need to increase genetic variability to obtain materials with a significant capacity to drought tolerance, this study conducted a cycle of a reciprocal recurrent selection of full-sib families of maize. To this end, 64 full-sib families of maize were evaluated in two environments according to their morpho-agronomic data in a randomized block design with two replicates. It were analyzed of Male flowering (MF); Female flowering (FF); Flowering interval (IF); days for flowering (DF); Plant height (PH); Ear height (EH); number of plants at the Stand (NPS); Number of broken plant (NBrP); Number of bedded plants (NBeP); Strawing (St); Ear length (EL); Ear diameter (ED); Ear number (EN); Prolificacy (Pr); Number of diseased ears (NDE); Number of ears attacked by pests (NEP); Ear weight (EW); Yield (YIE) and Total Chlorophyll Index (TCI). The analysis of variance was performed by the F test at 5% significance level, and also the evaluation of genetic parameters. Regarding morpho-agronomic data, the analysis of variance and the analysis of genetic parameters showed that there was no interaction genotype x environment with regard to the genetic variability among the families under study. Lastly, the final selection of the superior genotypes was made on the basis of the ranking of the 40 most productive families, from which, combined with the molecular data, the 30 most productive, most drought-tolerant, and most genetically diverse ones were selected to compose the next cycle of recurrent maize selection aiming water-stress tolerance.

Tendo em vista a necessidade de aumentar a variabilidade genética para obter materiais com significativa capacidade de tolerância à seca, este estudo conduziu um ciclo de seleção recorrente recíproca de famílias de irmãos completos de milho. Para tanto, 64 famílias de irmãos completos de milho foram avaliadas em dois ambientes de acordo com seus dados morfoagronômicos em um delineamento de blocos casualizados com duas repetições. Foram analisados o florescimento masculino (MF); florescimento feminino (FF); Intervalo de florescimento (IF); dias para florescimento (DF); Altura da planta (PH); Altura da espiga (EH); número de plantas na parcela (NPS); Número de planta quebrada (NBrP); Número de plantas com acamadas (NBeP); empalhamento (St); Comprimento da espiga (EL); Diâmetro da espiga (DE); Número de espigas (EN); Prolificidade (Pr); Número de espigas doentes (EQM); Número de espigas atacadas por pragas (NEP); Peso de espiga (EW); Rendimento de grãos (YIE) e Índice de clorofila total (TCI). A análise de variância foi realizada pelo teste F com nível de significância de 5% e também pela avaliação dos parâmetros genéticos. Em relação aos dados morfoagronômicos, a análise de variância e a análise dos parâmetros genéticos mostraram que não houve interação genótipo x ambiente no que diz respeito à variabilidade genética entre as famílias em estudo. Por fim, a seleção final dos genótipos superiores foi feita com base no ranking das 40 famílias mais produtivas, das quais, combinadas com os dados moleculares, foram selecionadas as 30 mais produtivas, mais tolerantes à seca e mais geneticamente diversificadas. para compor o próximo ciclo de seleção recorrente de milho visando tolerância ao estresse hídrico.

Combining ability of recombined F4 papaya lines: a strategy to select hybrid combination

The growing demand for quality of papaya by the domestic and international markets requires the development of genotypes that are capable of incorporating traits, such as high yield and fruit quality. This study estimated the genetic parameters and the specific combining ability of F4 papaya lines crossed to the SS-72/12 tester to identify genotypes with higher genetic value for hybrid production. We evaluated 169 treatments consisting of 62 topcross hybrid combinations, 97 F5 lines, and 10 controls in a 13 × 13 lattice design with five replicates and two plants per plot. The following traits were evaluated: plant height (PH), stem diameter (SD), first-fruit insertion height (FFIH), number of marketable fruits (NMF), number of deformed fruits (NDF), number of fruitless nodes (NFN), average fruit weight (FW), and yield (YLD). Differences p < 0.05 were found in most traits evaluated. The specific combining ability estimates indicate that hybrids formed by the cross between SS-72/12 tester and the following lines are promising, considering the multiple traits: UCLA08-088, UCLA08-101, UCLA08-071, UCLA08-014, UCLA08-025, UCLA08-028, UCLA08-122, UCLA08-055, UCLA08-026, and UCLA08-092. These hybrids meet the demands for domestic and international markets and may be available to producers as new papaya cultivars.

Combining ability of recombined F4 papaya lines: a strategy to select hybrid combination

The growing demand for quality of papaya by the domestic and international markets requires the development of genotypes that are capable of incorporating traits, such as high yield and fruit quality. This study estimated the genetic parameters and the specific combining ability of F4 papaya lines crossed to the SS-72/12 tester to identify genotypes with higher genetic value for hybrid production. We evaluated 169 treatments consisting of 62 topcross hybrid combinations, 97 F5 lines, and 10 controls in a 13 × 13 lattice design with five replicates and two plants per plot. The following traits were evaluated: plant height (PH), stem diameter (SD), first-fruit insertion height (FFIH), number of marketable fruits (NMF), number of deformed fruits (NDF), number of fruitless nodes (NFN), average fruit weight (FW), and yield (YLD). Differences p < 0.05 were found in most traits evaluated. The specific combining ability estimates indicate that hybrids formed by the cross between SS-72/12 tester and the following lines are promising, considering the multiple traits: UCLA08-088, UCLA08-101, UCLA08-071, UCLA08-014, UCLA08-025, UCLA08-028, UCLA08-122, UCLA08-055, UCLA08-026, and UCLA08-092. These hybrids meet the demands for domestic and international markets and may be available to producers as new papaya cultivars.(AU)

A two-location trial for selecting corn silage hybrids for the humid tropic: forage and grain yields and in vitro fermentation characteristics

The goal of our study was to evaluate the nutritional potential of dented corn hybrids for silage production. We performed a two-location trial in which 19 dented corn hybrids and five corn controls grew in four randomized blocks within two experimental areas located in the Northern (Campos dos Goytacazes) and Northwestern (Itaocara) Rio de Janeiro State, Brazil. We recorded yields of fresh and dry forage matter and yields of fresh and dry grain matter, as well as chemical composition variables. We interpreted variables by assuming a Normal distribution for yield variables and a Beta distribution for chemical composition and ratios. The SAS GLIMMIX procedure fitted the linear model under those assumptions. Dual-pool models fitted the gas production profiles generated by in vitro anaerobic fermentations. We used the nlme of R software to fit the dual-pool models and the information-theoretic approach to evaluate their quality of fit. We did a cluster analysis (NbClust of R) to group corn hybrids based on fresh and DM yields and kinetic parameters of in vitro gas production. Three clusters of corn hybrids stood out, their basic differences relied on fresh and DM yields. Nonetheless, the least-squares means for gas production characteristics among groups did not present disjoint confidence intervals. Therefore, we can infer that dented corn hybrids rank by forage yield, but not by forage quality, and recommend the most productive ones that consistently outstand in both locations (hybrids UENF-2203, UENF-2192, UENF-2193, and UENF-506-11).

Papaya recombinant inbred lines selection by image-based phenotyping

The selection of superior Carica papaya (L) genotypes depends on the availability of genetic variability and on the favorable and simultaneous response of the genotypes to those traits of most interest. However, manual phenotyping (MP) demands intensive labor, is time-consuming and expensive. The aim of the current study is to access the efficiency of image-based phenotyping (IBP) in estimating genetic parameters and in selecting F4 recombinant inbred lines. The genetic parameters and values were estimated in accordance with the REML/BLUB procedure and combined selection using the selection index based on standardized genetic values. The majority of traits accessed through IBP showed experimental coefficients of variation similar to those found through MP. Both methodologies showed genetic parameters of similar magnitude, indicating expressive genetic variability between lines in the traits accessed in this study. The same superior lines were indicated in both methodologies and expressive genetic gains obtained through the lines were selected for all traits. IBP performance was similar to that of MP with respect to the estimates of breeding-relevant traits such as commercial fruits and yield. Thus, IBP showed efficient phenotypic assessment, as well as selective accuracy in accessing genetic variability and genetic gains, when it was compared to MP. Since IBP is far less dependent on labor, it is expected to be incorporated into the routine of papaya breeding programs as a way of increasing the number of accessed lines and, consequently, increasing genetic gains.

Papaya recombinant inbred lines selection by image-based phenotyping

The selection of superior Carica papaya (L) genotypes depends on the availability of genetic variability and on the favorable and simultaneous response of the genotypes to those traits of most interest. However, manual phenotyping (MP) demands intensive labor, is time-consuming and expensive. The aim of the current study is to access the efficiency of image-based phenotyping (IBP) in estimating genetic parameters and in selecting F4 recombinant inbred lines. The genetic parameters and values were estimated in accordance with the REML/BLUB procedure and combined selection using the selection index based on standardized genetic values. The majority of traits accessed through IBP showed experimental coefficients of variation similar to those found through MP. Both methodologies showed genetic parameters of similar magnitude, indicating expressive genetic variability between lines in the traits accessed in this study. The same superior lines were indicated in both methodologies and expressive genetic gains obtained through the lines were selected for all traits. IBP performance was similar to that of MP with respect to the estimates of breeding-relevant traits such as commercial fruits and yield. Thus, IBP showed efficient phenotypic assessment, as well as selective accuracy in accessing genetic variability and genetic gains, when it was compared to MP. Since IBP is far less dependent on labor, it is expected to be incorporated into the routine of papaya breeding programs as a way of increasing the number of accessed lines and, consequently, increasing genetic gains.(AU)

Diallel mixed-model analysis of papaya fruit deformities / Análise dialélica via modelos mistos das deformidades em frutos de mamoeiro

Changes in the shape of fruits from hermaphrodite flowers due to floral anomalies are quite common. The aim of this study was to estimate the effects of the general and specific combining ability on the proportions of normal and deformed (carpelloid and pentandric) papaya fruits in hermaphrodite plants using mixed models. The JS12-N, Waimanalo and Golden parents showed the potential to decrease the number of deformed fruits. In contrast, the Maradol x JS12-N, Maradol x Waimanalo, Maradol x Golden, JS12-N x JS12-4, JS12-N x Sekati, JS12-N x Waimanalo, Waimanalo x JS12-N, Waimanalo x JS12-4, Waimanalo x Golden, Waimanalo x Sunrise Solo 72/12, Golden x Maradol, Golden x JS12-N, Golden x Sekati, Golden x Waimanalo and São Mateus x JS12-N hybrids have the potential to increase the number of marketable fruits while decreasing the number of carpelloid and pentandric fruits.

Alterações na forma dos frutos originários de flores hermafroditas são bastante comuns. Estas alterações são provocadas por anomalias florais. Este trabalho teve como objetivo obter via modelos mistos estimativas de capacidade geral e específica de combinação para proporção de frutos de mamoeiro normais e com deformidades: carpeloidia e pentandria, em plantas hermafroditas. Os genitores JS12-N, Waimanalo e Golden apresentam potencial para redução de frutos com deformidades. Os híbridos Maradol x JS12-N, Maradol x Waimanalo, Maradol x Golden, JS 12-N x JS12-4, JS 12-N x Sekati, JS 12-N x Waimanalo, Waimanalo x JS12-N, Waimanalo x JS12-4, Waimanalo x Golden, Waimanalo x Sunrise Solo 72/12, Golden x Maradol, Golden x JS12-N, Golden x Sekati, Golden x Waimanalo e São Mateus x JS12-N apresentaram potencial para aumento do número de frutos comerciais e redução de frutos carpelóides e pentândricos.

Diallel mixed-model analysis of papaya fruit deformities / Análise dialélica via modelos mistos das deformidades em frutos de mamoeiro

Changes in the shape of fruits from hermaphrodite flowers due to floral anomalies are quite common. The aim of this study was to estimate the effects of the general and specific combining ability on the proportions of normal and deformed (carpelloid and pentandric) papaya fruits in hermaphrodite plants using mixed models. The JS12-N, Waimanalo and Golden parents showed the potential to decrease the number of deformed fruits. In contrast, the Maradol x JS12-N, Maradol x Waimanalo, Maradol x Golden, JS12-N x JS12-4, JS12-N x Sekati, JS12-N x Waimanalo, Waimanalo x JS12-N, Waimanalo x JS12-4, Waimanalo x Golden, Waimanalo x Sunrise Solo 72/12, Golden x Maradol, Golden x JS12-N, Golden x Sekati, Golden x Waimanalo and São Mateus x JS12-N hybrids have the potential to increase the number of marketable fruits while decreasing the number of carpelloid and pentandric fruits.(AU)

Alterações na forma dos frutos originários de flores hermafroditas são bastante comuns. Estas alterações são provocadas por anomalias florais. Este trabalho teve como objetivo obter via modelos mistos estimativas de capacidade geral e específica de combinação para proporção de frutos de mamoeiro normais e com deformidades: carpeloidia e pentandria, em plantas hermafroditas. Os genitores JS12-N, Waimanalo e Golden apresentam potencial para redução de frutos com deformidades. Os híbridos Maradol x JS12-N, Maradol x Waimanalo, Maradol x Golden, JS 12-N x JS12-4, JS 12-N x Sekati, JS 12-N x Waimanalo, Waimanalo x JS12-N, Waimanalo x JS12-4, Waimanalo x Golden, Waimanalo x Sunrise Solo 72/12, Golden x Maradol, Golden x JS12-N, Golden x Sekati, Golden x Waimanalo e São Mateus x JS12-N apresentaram potencial para aumento do número de frutos comerciais e redução de frutos carpelóides e pentândricos.(AU)

Model-assisted phenotyping by digital images in papaya breeding program

Manual phenotyping for papaya Carica papaya (L) breeding purposes limits the evaluation of a great number of plants and hampers selection of superior genotypes. This study aimed to validate two methodologies for the phenotyping of morpho-agronomic plant traits using image analysis and fruit traits through image processing. In plants of the THB variety and UENF/Caliman-01 hybrid two images (A and B) were analyzed to estimate commercial and irregularly shaped fruits. Image A was also used in the estimation of plant height, stem diameter and the first fruit insertion height. In THB fruits, largest and smallest diameters, length, and volume were estimated by using a caliper and image processing (IP). Volume was obtained by water column displacement (WCD) and by the expression of ellipsoid approximation (EA). Correlations above 0.85 between manual and image measurements were obtained for all traits. The averages of the morpho-agronomic traits, estimated by using images, were similar when compared to the averages measured manually. In addition, the errors of the proposed methodologies were low compared to manual phenotyping. Bland-Altman's approach indicated agreement between the volume estimated by WCD and EA using caliper and IP. The strong association obtained between volume and fruit weight suggests the use of regression to estimate this trait. Thus, the expectation is that image-based phenotyping can be used to expand the experiments, thereby maintaining accuracy and providing greater genetic gains in the selection of superior genotypes.

Model-assisted phenotyping by digital images in papaya breeding program

Manual phenotyping for papaya Carica papaya (L) breeding purposes limits the evaluation of a great number of plants and hampers selection of superior genotypes. This study aimed to validate two methodologies for the phenotyping of morpho-agronomic plant traits using image analysis and fruit traits through image processing. In plants of the THB variety and UENF/Caliman-01 hybrid two images (A and B) were analyzed to estimate commercial and irregularly shaped fruits. Image A was also used in the estimation of plant height, stem diameter and the first fruit insertion height. In THB fruits, largest and smallest diameters, length, and volume were estimated by using a caliper and image processing (IP). Volume was obtained by water column displacement (WCD) and by the expression of ellipsoid approximation (EA). Correlations above 0.85 between manual and image measurements were obtained for all traits. The averages of the morpho-agronomic traits, estimated by using images, were similar when compared to the averages measured manually. In addition, the errors of the proposed methodologies were low compared to manual phenotyping. Bland-Altman's approach indicated agreement between the volume estimated by WCD and EA using caliper and IP. The strong association obtained between volume and fruit weight suggests the use of regression to estimate this trait. Thus, the expectation is that image-based phenotyping can be used to expand the experiments, thereby maintaining accuracy and providing greater genetic gains in the selection of superior genotypes.(AU)

Predicting the genetic gain in the Brazilian white maize landrace / Predição de ganho genético em população crioula de milho branco

The objectives of this research were to evaluate the genetic variability and predict genetic gain in the white maize landrace rescued in Barbacena, Minas Gerais, Brazil. The Brazilian maize landraces have economic and social importance for certain areas in Brazil, and research on this germplasm is very important for local food security. Three experiments were carried out with 100 half-sib progenies, in Campos dos Goytacazes, RJ, Coimbra and Barbacena, Minas Gerais, Brazil. These sites were chosen for their soil and climatic differences. An analysis of variance was significant among the progeny for all characters, indicating the presence of genetic variability between the three populations. In Campos dos Goytacazes and Coimbra, the genetic variation of the white maize landrace was responsible for most of the phenotypic variance in grain yield and can be used in selection cycles. There was no significant genetic variance in grain yield in Barbacena. For the white maize landrace it was concluded that: the characters of the component of productivity such as plant density and number of plants with kernels can produce indirect genetic gain for grain yield and are suitable for breeding; prebreeding of the maize landrace is necessary before being used directly in the elite germplasm; the population contains high genetic variability and opportunities for genetic gain; the average agronomic traits are suitable only for traditional production systems with few inputs, and polyculture; the difference between environments produces specific responses in the progeny i.e. there is a progeny x environment interaction.(AU)

Os objetivos deste trabalho foram avaliar a variabilidade genética e predizer os ganhos genéticos de uma população crioula de milho branco resgatada em Barbacena, Minas Gerais (MG), devido à importância social e econômica do milho branco em determinadas localidades brasileiras, à manutenção e ao resgate de populações crioulas e aos poucos trabalhos sobre esse tipo de grão. Para tanto foram instalados três experimentos, com 100 progênies de meios-irmãos, em Campos dos Goytacazes, Rio de Janeiro (RJ), Coimbra e Barbacena (MG), escolhidos pelas diferenças edafoclimáticas. Pela análise de variância foram verificadas diferenças significativas entre as progênies para todos os caracteres, o que indicou a presença de variabilidade genética na população para os três locais. Em Campos dos Goytacazes e Coimbra, a variância genética da população crioula de milho branco foi responsável pela maioria da variância fenotípica para produtividade de grãos, podendo ser explorada em ciclos de seleção. Em Barbacena, não foi detectada variância genética significativa para a produtividade de grãos. Para a população crioula de milho branco Barbacena, conclui-se que caracteres do componente primário de produtividade como estande final e número de plantas com grãos podem apresentar ganhos genéticos direto e indireto com a produtividade e são adequados para o melhoramento. No entanto, é necessário o pré-melhoramento da população antes desta ser utilizada diretamente em germoplasma elite. Além disso, foi observado que a população apresenta variabilidade genética e ganhos genéticos preditos altos; as médias das características agronômicas são adequadas somente para o sistema produtivo tradicional com poucos insumos e policultivo; e a diferença entre os ambientes proporciona resposta específica das progênies, ou seja, interação progênie x ambiente.(AU)