ABSTRACT. To be considered drought-tolerant, a tomato cultivar is required to present some level of tolerance at all developmental stages of plant growth. Since drought tolerance is a stage-specific phenomenon, genotype assessment must be performed separately at all developmental stages. In this study, we used a multi-trait index based on factor analysis and genotype-ideotype distance (FAI-BLUP index) to properly rank 49 tomato genotypes according to their tolerance to drought stress conditions at germination and seedling stages. Seeds of 47 introgression lines, which cultivar M82 is considered drought-sensitive, and the Solanum pennellii wild accession LA 716, which is considered drought-tolerant, were subjected to a control condition, where seeds were soaked in distilled water, and a drought condition, where seeds were soaked in a polyethylene glycol (PEG) solution (-0.3 MPa). Drought stress, induced by PEG, had a significant impact on all nine germination and growth performance-related traits; there was a reduction in shoot length (SL), total length (TL), initial germination percentage (IGP), final germination percentage (FGP), germination velocity index (GVI), and germination rate (GR). In contrast, the root-to-shoot ratio (R/S) and time to reach 50% germination (T50) increased under drought stress. Root length (RL) was less affected by drought, and in some genotypes, it was even increased. As expected, LA 716 ranked closest to the drought tolerance ideotype. IL 1-4-18, IL 2-3, IL 1-2, IL 9-2, and IL 10-1 were the most drought-tolerant at the germination stage. These results will serve as guidance for breeders who are aiming at developing drought-resistant tomato cultivars.

ABSTRACT. The selection of superior genotypes of soybean entails a simultaneous evaluation of a number of favorable traits that provide a comparatively superior yield. Disregarding the population effect in the statistical model may compromise the estimate of variance components and the prediction of genetic values. The present study was undertaken to investigate the importance of including population effect in the statistical model and to determine the effectiveness of the index based on factor analysis and ideotype design via best linear unbiased prediction (FAI-BLUP) in the selection of erect, early, and high-yielding soybean progenies. To attain these objectives, 204 soybean progenies originating from three populations were examined for various traits of agronomic interest. The inclusion of the population effect in the statistical model was relevant in the genetic evaluation of soybean progenies. To quantify the effectiveness of the FAI-BLUP index, genetic gains were predicted and compared with those obtained by the Smith-Hazel and Additive Genetic indices. The FAI-BLUP index was effective in the selection of progenies with balanced, desirable genetic gains for all traits simultaneously. Therefore, the FAI-BLUP index is an adequate tool for the simultaneous selection of important traits in soybean breeding.

ABSTRACT Combining longitudinal data and statistical models from perennial crops enabled us to estimate the optimum number of measures (harvests), implying accurate discrimination of superior genotypes in those crops. Herein, the goal of this study was to determine the optimum number of harvests based on yield traits and recommend a superior graft/rootstock combination (GRC) for Citrus latifolia Tanaka. Twenty-four GRCs of 'Tahiti' acid lime were evaluated from July 2017 to August 2018 for fruit yield per plant (FYP), number of fruits per plant (NFP), and longitudinal (LFD) and transversal fruit diameter (TFD). The experimental design was a randomized complete block with 4 replications. The experimental unit consisted of three individuals, totalling 244 individuals. The GRCs were composed of (i) two hybrids that were used as rootstock, citrumelo ‘Swingle’ (Citrus paradisi x Poncirus trifoliata) and cintrandarin ‘Riverside’ (Citrus sunki x Poncirus trifoliata); and (ii) 12 different C. latifolia genotypes that were used as grafts: Bello Fruit, Eledio, Iconha, Itarana, Santa Rosa, Bearss lime, CNPMF 01, CNPMF 02, CNPMF 2001, CNPMF 5059, BRS Passos, and Persian 58. Mixed models were employed to estimate the variance components. The optimum number of harvests was determined based on selective efficiency values above 0.9. The estimated repeatability coefficients presented values of 0.14 (LFD), 0.16 (TFD), 0.36 (FYP), and 0.38 (NFD). Based on the results, four harvests were able to choose genotypes based on FYP and NFP, whereas LFD and TFD were considered inefficient traits for recommending superior GRCs.

ABSTRACT Tree breeders are prioritizing the increase of the interspecific diversity in the breeding programs due to the pronounced environmental changes, and expansion of the forest frontier to less productive areas. In this scenario, there is a growing interest for species of the genus Corymbia due to their good growth, resistance to biotic and abiotic factors, and industrial properties. Also, Corymbia spp. can cross with each other, generating interspecific hybrids. However, there are great difficulties on defining the best crosses. Thus, the objectives of this study were to evaluate the genetic variability of 64 progenies of Corymbia maculata and 64 progenies of Corymbia torelliana and to use the GGE biplot method to point the most appropriated crosses to broad and specific environments in order to generate stable and productive interspecific hybrids of C. maculata and C. torelliana. The GGE biplot was an efficient method for evaluating the genetic variability between progenies, for visualizing the genotype by environment interaction pattern and for identifying the best crosses in order to generate interspecific hybrids of the species. By adopting a selection intensity of 10%, the recommended progenies to generate interspecific hybrids for the Aracruz municipality (ARA) were 10, 40, 49, 64, 20, 9 and 47 of C. maculata and 24, 56, 41, 64, 43, 31 and 12 of C. torelliana. For Três Lagoas municipality (TLA), the recommended progenies were 11, 17, 1, 48, 7, 63 and 21 of C. maculata and 42, 46, 61, 44, 10, 63 and 28 of C. torelliana.

ABSTRACT An accurate, efficient and informative statistical method for analyses of genotype × environment (G × E) interactions is a key requirement for progress in any breeding program. Thus, the objective of this study was to quantify individual variation in reaction norms using random regression models fitted through Legendre polynomials in eucalyptus (Eucalyptus spp.) breeding. To this end, a data set with 215 eucalyptus clones of different species and hybrids evaluated in four environments for diameter at breast height (DBH) and Pilodyn penetration (PP) was used. Variance components were estimated by restricted maximum likelihood, and genetic values were predicted by best linear unbiased prediction. The best-fitted model for DBH and PP was indicated by the Akaike information criterion, and the significance of the genotype effects was tested using the likelihood ratio test. Genetic variability between eucalyptus clones and very high accuracies ( r g ^ g ≥ 0 . 90) were detected for both traits. Reaction norms and eigenfunctions generated genetic insights into G × E interactions. This is the first study that quantified individual variation in reaction norms using random regression models fitted through Legendre polynomials in eucalyptus breeding and demonstrated the great potential of this technique.

ABSTRACT Jatropha curcas L. is a perennial plant with great potential for biodiesel production. Thus, the aim of this study was to select J. curcas genotypes for bioenergy purpose considering multitrait, multiharvest and effective population size. To this end, a data set with 70 J. curcas families, obtained through controlled crosses, evaluated in a randomized block design, with six replications, three plants per plot, spaced at 4 × 2 m was used. The following traits were evaluated: plant height in the 2014 and 2015 crop seasons; canopy projection in the row (2015 crop season); canopy projection between rows (2015 crop season); and grain yield (2015, 2016, and 2017 harvests). The mixed model methodology was used to estimate the variance components and to predict the genetic values. Superior genotypes were selected through Multitrait index based on factor analysis and genotype-ideotype distance (FAI-BLUP index), considering the effective population size. According to this index, 98% of all additive genetic variability were summarized in three factors. By adopting the selection intensity that allows maintaining the effective population size equal to 30 (i.e., selection of 214 individuals), the predicted gains were 15.56, 21.75, 4.16, and 5.37% for the traits grain yield in the 2015 and 2016 harvests, canopy projection in the row, and canopy projection between rows in the 2015 crop season, respectively. Thus, the results suggest that the FAI-BLUP index can be successfully used in J. curcas breeding.

Resumo: Estudos da transmissão de Pyricularia graminis-tritici pela semente de trigo podem auxiliar no estabelecimento de padrões de tolerância do patógeno na cultura. Quatro genótipos diferentes quanto à reação à brusone foram inoculados com cinco volumes da suspensão fúngica (1,5x105 esporos.mL-1), de modo a obter 0, 5, 10, 20 e 30% de plantas inoculadas na unidade experimental. O potencial de transmissão de P. graminis-tritici planta-semente foi avaliado pela incidência do fungo nas sementes produzidas. Em condições controladas, avaliou-se a taxa de transmissão do fungo da semente à plântula. A incidência da brusone no campo possibilitou elevada incidência de P. graminis-tritici nas sementes, principalmente nos genótipos considerados suscetíveis. Ocorreu transmissão do fungo da semente para plântula aos 7, 14 e 21 dias após a semeadura e as taxas foram baixas. Existe relação entre a presença da brusone no campo e a incidência de P. graminis-tritici nas sementes produzidas pelos genótipos BRS 264, VI 98053, CD 116 e CD 104. A inoculação de 5, 10, 20 e 30% de plantas com o fungo pode gerar alta incidência do patógeno no campo e nas sementes produzidas, mas não garante elevada taxa de transmissão da semente para a plântula, que é baixa em condições controladas.

Abstract: Transmission studies of Pyricularia graminis-tritici by wheat seed can help establishing pathogen tolerance standards in crops. Four genotypes, each one with different responses to blast, were inoculated with five volumes of fungal suspension (1,5x105 spores.mL-1), in order to obtain 0, 5, 10, 20 and 30% of plants inoculated in the experimental unit. The potential of transmission of P. graminis-tritici from plant to seed was evaluated by the incidence of the fungus in the seeds produced. Under controlled conditions, the transmission rate of the fungus from seed to seedling was evaluated. Blast incidence in field allowed a high incidence of P. graminis-tritici in the seeds, especially in the genotypes considered susceptible. The transmission of fungus from the seeds to seedlings occurred 7, 14 and 21 days after sowing, at low rates. There was a relationship between the presence of blast in field and the incidence of P. graminis-tritici in seeds produced by the genotypes BRS 264, VI 98053, CD 116 and CD 104. Inoculation of 5, 10, 20 and 30% of plants with fungus can generate a high incidence of the pathogen in field and in the seeds produced, but it doesn`t guarantee a high transmission rate from seed to seedling, which is low under controlled conditions.

A necessidade de obtenção de cultivares de trigo tolerantes ao calor, para a consequente expansão da área de cultivo para regiões mais quentes, é premente, diante da alta demanda desse cereal para alimentação humana. O objetivo deste trabalho foi avaliar o efeito da temperatura elevada sobre a produtividade de grãos de trigo e os componentes da produção, além de caracterizar genótipos de trigo quanto à tolerância ao calor em diferentes estádios de desenvolvimento. Os genótipos foram avaliados em campo, em presença e ausência de estresse de calor. A temperatura elevada reduziu o número de espiguetas/espiga (21%), número de grãos por espiga (39%), número de grãos por espigueta (23%), massa de mil grãos (27%) e produtividade de grãos (79%). Os cultivares MGS 1 Aliança, Embrapa 42, IAC 24-Tucuruí e IAC 364-Tucuruí III são mais tolerantes ao estresse de calor entre o estádio de duplo anel e espigueta terminal; MGS 1 Aliança, BRS 264, IAC 24-Tucuruí, IAC 364-Tucuruí III e VI 98053, entre a meiose e a antese; e BRS 254, IAC 24-Tucuruí, IAC 364-Tucuruí III e VI 98053, entre a antese e a maturação fisiológica. A temperatura elevada diminui a produtividade de grãos e os componentes da produção. O número de grãos/espiga é o componente que mais se reduz sob condições de estresse de calor. Os genótipos de trigo diferem quanto ao estádio fenológico em que são mais tolerantes ao estresse de calo

Abstract: There is a need for heat tolerant wheat cultivars adapted to the expansion of cultivation areas in warmer regions due to the high demand of this cereal for human consumption. The objective of this study was to evaluate the effect of high temperatures on grain yield and yield components of wheat and characterize heat tolerant wheat genotypes at different development stages. The genotypes were evaluated in the field with and without heat stress. High temperatures reduced the number of spikelets per spike (21%), number of grains per spike (39%), number of grains per spikelet (23%), 1000-grain weight (27%) and grain yield (79%). Cultivars MGS 1 Aliança, Embrapa 42, IAC 24-Tucuruí and IAC 364-Tucuruí III are the most tolerant to heat stress between the stages double ridge and terminal spikelet; MGS 1 Aliança, BRS 264, IAC 24-Tucuruí, IAC 364-Tucuruí III and VI 98053, between meiosis and anthesis; and BRS 254, IAC-24-Tucuruí, IAC-364-Tucuruí III and VI 98053, between anthesis and physiological maturity. High temperatures reduce grain yield and yield components. The number of grains per spike is the most reduced component under heat stress. The genotypes differed in tolerance to heat stress in different developmental stages.

Causada pelo fungo Pyricularia grisea, a brusone do trigo constitui-se num dos principais entraves à expansão da produção tritícola no Brasil Central. O objetivo deste trabalho foi avaliar a eficiência de fungicidas no controle da brusone em trigo. Foram utilizados três fungicidas, com princípios ativos distintos, combinados com quatro genótipos de trigo. Realizaram-se duas aplicações do produto comercial, sendo estas no estádio 45 e 65 da escala de Zadokset al. A inoculação artificial com os esporos de P. grisea ocorreu no estádio 58-60 da referida escala. Determinou-se a área abaixo da curva de progresso da doença (AACPD), a severidade em folhas bandeira (SEVFB) e em espigas (SEVEsp) e quantificou-se a produção de grãos (PG).Ao final do trabalho, os diferentes parâmetros analisados foram submetidos à análise de correlação de Pearson.Os fungicidas epoxiconazol+piraclostrobina e tebuconazol+trifloxistrobina foram os que proporcionaram menor AACPD nos genótipos VI 03061, VI 07505 e BRS 254. Não houve diferença para SEVFB entre os genótipos na presença de fungicidas. As linhagens VI 98053 e VI 07505 apresentam menor SEVFB na ausência de fungicidas.O fungicida tebuconazole+trifloxistrobina proporcionou maior PG e menor SEVEsp. A severidade da doença em espigas foi maior do que em folhas bandeira. O controle da brusoneem trigo através da aplicação de fungicidas mostrou-se eficiente em folhas bandeira, mas não eficiente para o controle nas espigas.

Wheat blast, caused by the fungus Pyricularia grisea, constitutes one of the major obstacles to the expansion of wheat production in Central Brazil. The aim of this study was to evaluate the efficiency of fungicides in the control of wheat blast. Three fungicides with different active ingredients and combined with four wheat genotypes were used. Two applications of the commercial product were performed in stages 45 and 65 of the scale of Zadoks et al. Artificial inoculation with P. grisea spores was done in stages 58-60 of the above-mentioned scale. The area under the disease progress curve (AUDPC), the severity on flag leaves (SEVFL) and the severity on spikes (SEVEsp) were determined, and grain yield (GY) was quantified. At the end of the experiment, different analyzed parameters were subjected to Pearson's correlation analysis. The fungicides epoxiconazole+pyraclostrobin and tebuconazole+trifloxystrobin provided the lowest AUDPC for the genotypes VI 03061, VI 07505 and BRS 254. There was no difference for SEVFL among genotypes in the presence of fungicides. The genotypes VI 98053 and VI 07505 showed the lowest SEVFL in the absence of fungicide. Tebuconazole+trifloxystrobin provided higher GY and lower SEVEsp. The disease severity on the ears was greater than on flag leaves. Control of wheat blast by means of fungicide application was effective for flag leaves but not for ears.

O objetivo deste trabalho foi estimar os parâmetros genéticos e predizer o valor genético de populações e indivíduos oriundos de populações segregantes de trigo, com o uso da metodologia de modelos mistos ("restricted maximum likelihood"/"best linear unbiased prediction", REML/BLUP). Trinta e seis populações segregantes de trigo e quatro controles foram avaliados na geração F3, em delineamento de blocos ao acaso, com informações de indivíduo retiradas de dentro das parcelas. Os caracteres avaliados foram: produção de grãos, índice de colheita, número de perfilhos e altura de planta. Observou-se a existência de variabilidade genética entre populações em todos os caracteres avaliados. A herdabilidade média variou de 39,15 a 92,78%, e a acurácia, de 62,57 a 96,32%, na seleção de populações. A herdabilidade individual no sentido restrito foi baixa dentro das populações, em todos os caracteres. A acurácia na seleção individual apresentou magnitude média, quanto ao caráter altura de plantas, e baixa quanto aos demais caracteres. A herdabilidade individual contribui para maior ganho nos caracteres altura de planta e índice de colheita com o uso do BLUP individual, em comparação ao BLUP de populações. As populações segregantes Embrapa22/BRS207, Embrapa22/VI98053, Embrapa22/IVI01041, BRS254/BRS207, BRS254/VI98053, BRS254/UFVT1Pioneiro e BRS264/BRS207 destacam-se por apresentar valor genético aditivo elevado em dois ou mais caracteres.

The objective of this work was to estimate the genetic parameters and to predict the genotypic value of populations and individuals from wheat segregating populations, using the methodology of mixed models (restricted maximum likelihood/best linear unbiased prediction, REML/BLUP). Thirty-six wheat segregating populations and four controls were evaluated in the F3 generation, in a randomized complete block design, with individual information taken from within the plots. The evaluated traits were: grain yield, harvest index, number of tillers, and plant height. Genetic variability between populations was observed for all evaluated traits. The mean heritability varied from 39.15 to 92.78%, and accuracy varied from 62.57 to 96.32% in the selection of populations. The narrow-sense individual heritability was low within populations for all traits. The accuracy for individual selection had a moderate value for plant height, and low values for the other traits. Individual heritability contributes to a greater gain for the traits plant height and harvest index with the use of individual BLUP, in comparison to population BLUP. The segregating populations Embrapa22/BRS207, Embrapa22/VI98053, Embrapa22/IVI01041, BRS254/BRS207, BRS254/VI98053, BRS254/UFVT1Pioneiro, and BRS264/BRS207 stand out with high additive genetic value, for two or more traits.

O objetivo deste trabalho foi estimar, em gerações avançadas, os efeitos da capacidade geral e específica de combinação de genitores de trigo, bem como selecionar populações segregantes superiores. Doze genitores e suas 36 populações nas gerações F2 e F3, obtidas em arranjo de dialelo parcial, foram avaliados quanto à produtividade de grãos. Utilizou-se o delineamento em látice 7x7, com duas repetições, mais um tratamento para completar o látice. O efeito de capacidade geral de combinação foi significativo, nas duas gerações. Observou-se alta correlação (0,83) dos efeitos de capacidade geral de combinação entre gerações, mas inexpressiva influência dos efeitos de gerações e de anos na classificação dos cruzamentos. As populações provenientes do cruzamento entre os genitores BRS 254, BRS 264 e IAC 364 (Tucuruí III) e os genitores MGS 1 Aliança, VI 98053 e UFVT 1 Pioneiro apresentam maior potencial para obtenção de linhagens superiores, quanto à produtividade de grãos. O uso da análise dialélica parcial em gerações avançadas é promissor para programas de melhoramento de trigo por hibridação.

The objective of this work was to estimate the effects of general and specific combining ability of wheat parental lines in advanced generations, and to select superior segregating populations. Twelve parental lines and their 36 populations in F2 and F3 generations, obtained in a partial diallel arrangement, were evaluated for grain yield. The experimental design used was a 7x7 simple lattice with two replicates, plus a treatment to complete the lattice. The effect of general combining ability was significant in both generations. There was high correlation (0.83) of the effects of general combining ability between generations, but inexpressive influence of the effects of generations and years were observed on the classification of crossings. The populations derived from the crossings between the parental lines BRS 254, BRS 264, and IAC 364 (Tucuruí III) and the parental lines MGS 1 Aliança, VI 98053, and UFVT 1 Pioneiro show the greatest potential for obtaining superior lines for grain yield. The use of the partial diallel analysis in advanced generations is promising for wheat breeding programs through hybridization.