RESUMO O feijão-caupi verde é uma importante alternativa para a geração de emprego e renda para os agricultores familiares, contribuindo para expansão de sua produção e consumo. No entanto, fatores bióticos como insetos, fungos, bactérias, nematoides e vírus têm limitado sua produção, destacando-se os vírus Cowpea Severe Mosaic Virus (CPSMV) e Cowpea aphid-borne mosaic virus (CABMV). O controle mais eficiente desses vírus é por meio da utilização de variedades resistentes, porém poucas são as variedades destinadas para a produção de feijão verde que são resistentes. Dessa forma, objetivou-se desenvolver e identificar linhagens superiores de feijão-caupi quanto à resistência simultânea aos vírus CPSMV e CABMV com características associadas à produção de grãos verdes. Foram realizados cruzamentos em casa de vegetação no Instituto Agronômico de Pernambuco-AIP entre os genótipos Sempre Verde Salgueiro (suscetível), CNC-0434 (imune ao CPSMV) e TVu-966 (resistente ao CABMV). A partir dos cruzamentos foram selecionadas 50 linhagens F2:5 com coloração do grão tipo Sempre Verde, sendo avaliada a resistência aos vírus em casa de vegetação e as suas características agronômicas para produção de grãos verdes em experimento na Estação Experimental do AIP em Belém do São Francisco-PE. O delineamento experimental foi em blocos casualizados completos, com três repetições. As linhagens L300.026, L300.039, L300.040 e L300.049 mostraram-se resistentes a ambos os vírus e possuem elevado potencial para a produção de grãos verdes; o índice de seleção de Mulamba e Mock facilitou a seleção de linhagens superiores e promissoras para futuro lançamentos de novas variedades resistentes destinadas à produção de grãos verdes.

ABSTRACT Green cowpea is an important alternative for generating employment and income for family farmers and helps broaden production and consumption of the grain. However, biotic factors such as insects, fungi, bacteria, nematodes and viruses have hampered production, especially the Cowpea Severe Mosaic Virus (CPSMV) and Cowpea Aphid-Borne Mosaic Virus (CABMV). The most efficient control of these viruses is via the use of resistant varieties, but few varieties intended for green-grain production are resistant. As such, the aim of this study was to develop and identify superior strains of cowpea in terms of joint resistance to the CPSM and CABM viruses that show characteristics associated with green-grain production. Crosses were carried out in a greenhouse at the Agronomic Institute of Pernambuco (AIP) between the following genotypes: Sempre Verde Salgueiro (susceptible), CNC-0434 (immune to CPSMV) and TVu-966 (resistant to CABMV). From these crosses, fifty F2:5 strains with the Sempre Verde type of grain colouring were selected, their resistance to the viruses assessed in a greenhouse, and their agronomic characteristics for green-grain production evaluated in an experiment at the Experimental Station of the AIP in Belém do São Francisco, Pernambuco. The experimental design was of completely randomised blocks, with three replications. The L300.026, L300.039, L300.040 and L300.049 strains proved to be resistant to both viruses, with a high potential for green-grain production. The Mulamba-Mock selection index facilitated the selection of superior strains that are promising for the future launch of new resistant varieties destined for the production of green grains.

ABSTRACT The germplasm characterization and the analysis of genetic divergence are fundamental requirements to determine the genetic diversity available and peppers have considerable variability not most explored and quantified. Thus, the aim of this study was to characterize morphological and agronomically pepper accessions and their genetic divergence. The experiment was conducted in a greenhouse of the Department of Agronomy of the Universidade Federal Rural de Pernambuco, Recife, between the months of December 2014 to June 2015. Thirteen pepper accessions in pots were sown, the experimental design was a randomized block with six replications, and the experimental unit consisted of three pots. Seedling, leaves, plant and fruit characteristics were evaluated. For the analysis of genetic divergence, the Mahalanobis distance and the UPGMA method were used. It was observed the formation of three distinct groups, being fruit width the trait that most contributed to the genetic discrimination of the accessions. Group I presented larger fruits, Group II showed heavier and wider fruits and Group III had mostly smaller, lighter and thinner fruits. There were differences for most of the evaluated characteristics, showing great morphological and agronomic variability among the accessions. The peppers have a high potential to be exploited in breeding.

Abstract This study aimed to define a methodology that, when combined with temperature, can overcome the dormancy and also to determine the adequate substrate and light conditions for germination of Colubrina glandulosa Perkins, contributing to seed analysis and restoration projects. In the experiment of dormancy and temperature, seeds were immersed in sulfuric acid for 30, 60, 90, 120 and 150 minutes and set to germinate at temperatures of 20-30 °C, 25 °C and 30 °C. The used substrates were sand, vermiculite, Tropstrato® substrate, coconut powder, blotting paper and paper towel. As for the light supplied, the seeds were subjected to four luminosity regimes: white light, far-red light, red light and light absence. Temperatures of 20-30 °C and 30 °C achieved better results, with exposure in sulfuric acid for 120 and 150 minutes. The substrates sand and vermiculite were the most suitable. The species germinated in all light regimes treatments used.

ABSTRACT The cultivation of genotypes non-adapted to the cultivation region of interest is among the main factors responsible for low yield. The aim of the present study is to select hybrid maize through GGE biplot analysis and to assess its adaptability and stability in different environments in Northeastern Brazil. Twenty-five hybrid maize cultivars were assessed in ten different environments in Northeastern Brazil in 2012 and 2013 based on the randomized block design, with two replications. The analysis of variance and assessment of genotype adaptability and stability were made through GGE biplot analysis, based on grain yield. Analysis of variance results showed different performances depending on the genotype, as well as genotype/environment interaction. The biplot analysis was efficient on data interpretation and represented 63.73% of the total variation in the first two main components, it also allowed classifying the ten environments into three macro-environments. Most environments were positively correlated. Hybrids 2 B 604 HX, 30 A 95 HX, 2 B 587 HX and 2 B 710 HX were responsive and stable. Hybrid 30 A 16 HX was recommended for macro-environments2 and 3. Cultivar 30 A 68 HX was recommended to environment 1. São Raimundo das Mangabeiras and Nova Santa Rosa counties were discriminating and representative. Nossa Senhora das Dores, Umbaúba, Teresina, Brejo, Frei Paulo, Colinas and Balsa counties were ambiguous and non-recommended for further evaluations.

RESUMO A seleção genômica ampla (Genome Wide Selection - GWS) utiliza simultaneamente o efeito de milhares de marcadores cobrindo todo o genoma para predizer o valor genético genômico dos indivíduos no processo de seleção. Os possíveis benefícios de seu uso são a redução do ciclo de melhoramento, propiciando maior ganho por unidade de tempo e diminuição de custos. O sucesso da GWS está atrelado a escolha do método de predição dos efeitos dos marcadores. Assim, neste trabalho, visou-se aplicar as redes neurais artificiais (Artificial Neural Networks - ANNs), com a finalidade de predizer os valores genéticos genômicos (Genomic Breeding Values - GEBVs) baseado na estimação dos efeitos dos marcadores comparados a regressão de cumeeira - melhor preditor não viesado/seleção genômica ampla (Ridge Regression - Best Linear Unbiased Predictor/Genome Wide Selection - RR-BLUP/GWS). Foram efetuadas simulações por meio do software R, fornecendo as correlações referentes às ANNs e a RR-BLUP/GWS. Os métodos de predição foram avaliados utilizando correlações entre o valor fenotípico e valor genotípico com o valor genético genômico predito. Os resultados demonstraram superioridade das ANNs na predição dos GEBVs nos cenários com maior e menor densidade de marcadores, paralelo a níveis mais altos de desequilíbrio de ligação e maior herdabilidade.

ABSTRACT Genome-wide selection (GWS) uses simultaneously the effect of the thousands markers covering the entire genome to predict genomic breeding values for individuals under selection. The possible benefits of GWS are the reduction of the breeding cycle, increase in gains per unit of time, and decrease of costs. However, the success of the GWS is dependent on the choice of the method to predict the effects of markers. Thus, the objective of this work was to predict genomic breeding values (GEBV) through artificial neural networks (ANN), based on the estimation of the effect of the markers, compared to the Ridge Regression-Best Linear Unbiased Predictor/Genome Wide Selection (RR-BLUP/GWS). Simulations were performed by software R to provide correlations concerning ANN and RR-BLUP/GWS. The prediction methods were evaluated using correlations between phenotypic and genotypic values and predicted GEBV. The results showed the superiority of the ANN in predicting GEBV in simulations with higher and lower marker densities, with higher levels of linkage disequilibrium and heritability.

RESUMO: A exposição de plantas a condições de estresse múltiplo pode causar uma superprodução de espécies reativas de oxigênio promovendo desequilíbrio no sistema redox. O objetivo deste trabalho foi estudar a resposta antioxidante de variedades de cana-de-açúcar sob condições adversas visando a compreensão de mecanismos de defesa de genótipos tolerantes e sensíveis. Mudas micropropagadas de cana-de-açúcar de seis genótipos, RB966928, RB98710, RB855453, RB99395, RB867515 e RB855156 foram submetidas à avaliação da ação isolada do estresse por alta temperatura e da sua combinação com o estresse hídrico e salino. Avaliou-se a atividade das enzimas superóxido dismutase (SOD), catalase (CAT) e ascorbato peroxidase (APX), bem como a peroxidação lipídica (teor de MDA) e teor de peróxido de hidrogênio (H2O2), indicadores de estresse. A variedade RB867515 destacou-se por apresentar sincronia entre a atividade enzimática na regulação e desintoxicação das ROS, produzidas na célula vegetal durante situações de estresse ambiental, garantindo a manutenção do teor relativo de água sem incremento da peroxidação lipídica e, consequentemente, a manutenção dos processos fisiológicos e o crescimento da planta. Os resultados indicam que a peroxidação lipídica associada ao baixo teor relativo de água podem ser bons marcadores bioquímicos de sensibilidade da cana-de-açúcar à estresses múltiplos.

ABSTRACT: The exposure of plants to multiple stress conditions can cause over production of reactive oxygen species promoting an imbalance in the redox system. The aim of this study was to examine the antioxidant response from varieties of sugarcane under adverse conditions, to understand the defense mechanisms of tolerant and sensitive genotypes. Micropropagated sugarcane of six genotypes, RB966928, RB98710, RB855453, RB99395, RB867515, and RB855156, were subjected to isolated action of high-temperature stress and a combination of water and saline stress, and effects were evaluated. Activities of enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), as well as stress indicators such as lipid peroxidation (MDA content) and hydrogen peroxide (H2O2) content were evaluated. The RB867515 variety showed synchrony between the enzymatic activity and ROS regulation and detoxification, in the plant cell under environmental stress situations, thereby ensuring the maintenance of the relative water content without increment of lipid peroxidation; and consequently, the maintenance of physiological processes and plant growth. These results indicated that lipid peroxidation associated with relative water content can be good biochemical markers of sensitivity to multiple stresses in sugarcane.

Abstract The aim of the present study was to estimate the genetic improvement in the last recurrent selection cycles applied in two ‘Valenciana’ onion populations in Petrolina, PE. The experiments were carried out between October 2014 and January 2015, in Petrolina and Juazeiro, BA. The experiment consisted of a randomized block design, with 12 treatments and three replications. Analyses of variances were carried out separately for each population. The control population CNPH6400 was the comparison basis. Heritability and genetic gain were estimated for total (Prototal) and commercial (Procom) bulb yields. Significant differences were observed for Prototal and Procom in both populations and in both environments, except for the 25CA10 population, in Juazeiro. The highest Procom genetic gains were observed in Petrolina for 25CA10 and T811CR13 populations (510.5% and 522.1%, respectively), proving the efficiency of recurrent selection cycles. Genetic gains were nonlinear, and fluctuations may have occurred due to genetic drift.

Essential oils of Lippia sidoides, Lippia gracilis and their main chemical components were investigated for in vitro control of Thielaviopsis paradoxa. Mycelial growth and a number of pathogen conidia were inhibited by the essential oil of L. sidoides at all concentrations tested (0.2; 0.5; 1.0; 3.0 µL mL-1). L. sidoides oil contained 42.33% thymol and 4.56% carvacrol, while L. gracilis oil contained 10% thymol and 41.7% carvacrol. Mycelial growth and conidial production of T. paradoxa were completely inhibited by thymol at a 0.3 µL m-1 concentration. The results suggest that thymol could potentially be used for controlling coconut stem bleeding.

Objetivou-se, no presente trabalho, avaliar o comportamento de linhagens de alface quanto à resistência ao nematoide das galhas Meloidogyne javanica, identificando a provável existência de linhagens homozigotas para o caráter. Foram utilizados como tratamentos cinco linhagens F4 e seis linhagens F5, juntamente com as testemunhas 'Grand Rapids' (resistente) e 'Regina 71' (suscetível), além da cultivar de tomateiro Santa Clara. A semeadura foi feita em bandejas de poliestireno expandido, sendo o substrato infestado com ovos de M. javanica, na proporção de 30 ovos cm-3 de substrato. Aos quarenta e sete dias após a infestação, cada planta foi avaliada individualmente quanto aos seguintes caracteres: índice visual de galhas, número de ovos, fator de reprodução e índice de reprodução. Cada linhagem foi comparada com as testemunhas 'Regina 71' e 'Grand Rapids', para cada característica, através do teste de Dunnett (5%), obtendo-se a significância em relação a cada uma das testemunhas, permitindo a classificação de cada linhagem como homozigota resistente, homozigota suscetível ou segregante. Pelos resultados obtidos conclui-se que seis linhagens (AFX 018C 002 23 15, AFX 018C 002 23 22, AFX 018C 005 42 20, AFX 018C 005 44 22, AFX 018C 005 44 28 e AFX 022B 010 31) foram consideradas homozigotas resistentes para as características avaliadas, podendo ser utilizadas como novas fontes de resistência ao M. javanica em programas de melhoramento de alface.

The objective of the present work was to evaluate the behavior of lettuce lineages as for resistence to nematode from the Meloidogyne javanica root-knots, identifying probable existence of homozigote lineages for the characteristics. Five F4 and six F5 lineages were used as treatments together with the controls 'Grand Rapids' (resistent) and 'Regina 71' (susceptible), apart from the Santa Clara tomato plant cultivar. The sowing was done over expanded polystyrene trays with the substrate infested by M. javanica eggs in the proportion of 30 eggs cm-3 of substrat. At 47 days after infestation, each plant was evaluated individually as for the following characteristics: visual level of root-knots, number of eggs, level and factor of reproduction. Every lineage was compared to the 'Regina 71' and 'Grand Rapids' for each characteristic, through Dunnett (5%) test, obtaining the significance in relation to each control, allowing the classification of each lineage as resistant homozigote, susceptible homozigote or segregated. The results obtained showed that six lineages (AFX 018C 002 23 15, AFX 018C 002 23 22, AFX 018C 005 42 20, AFX 018C 005 44 22, AFX 018C 005 44 28 and AFX 022B 010 31) were considered resistant homozigote for the evaluated characteristics, and maybe being used as new sources of resistance to M. javanica in lettuce breeding program.

A divergência genética é um dos mais importantes parâmetros avaliados por melhoristas de plantas na fase inicial de um programa de melhoramento genético. O objetivo deste trabalho foi caracterizar 15 acessos de mamoneira por meio de caracteres morfoagronômicos. O experimento foi conduzido em Lavras, MG, no período de fevereiro a agosto de 2008. O delineamento experimental foi o de blocos ao acaso, com três repetições, e 25 plantas por parcela. Os caracteres avaliados foram: altura da planta, altura do caule, número de internódios, diâmetro do caule e número de racemos. Verificou-se a ocorrência de diferenças significativas pelo teste de F (P < 0,01), para o efeito de acessos para todas as variáveis estudadas. Foram estimadas as distâncias genéticas entre os acessos pelo método euclidiano. De acordo com o agrupamento, utilizando o método de Tocher e o método Hierárquico do "Vizinho Mais Próximo", baseado na distância euclidiana houve a formação de quatro grupos distintos. Com base nos resultados obtidos neste trabalho, recomendam-se os cruzamentos entre acessos dos grupos I e IV, II e IV, e III e IV.

Genetic divergence is one of the most important breeding parameters evaluated in the initial phase of a genetic improvement program. The objective of this work was to characterize 15 accessions of castor bean using morphoagronomic traits. The trial was carried out in Lavras, MG, Brazil, from February to August 2008. The experimental design was a randomized complete block design with three replicates and 25 plants per plot. The traits evaluated were: plant height (cm), stem height (cm), number of nodes, diameter of stem and number of clusters. Significant differences (F test: P < 0.01) were found for accession effects on all studied traits. Genetic distances among accessions were estimated using the Euclidean method. Four distinct groups were formed using the methods of Tocher and the hierarchical nearest neighbor clustering, based on the Euclidean distance. The results of this work indicate crossings between accessions from groups I and IV, II and IV and III and IV.

Um dos grandes desafios atuais da pesquisa agrícola é a produção de cultivares melhoradas de mamoneira, com estabilidade genética, alta qualidade e potencial produtivo. Objetivou-se, no presente trabalho, estimar as correlações genotípica, fenotípica e de ambiente entre caracteres de mamona para facilitar a caracterização dos acessos. Foram avaliados em Lavras, MG, no delineamento de blocos casualizados com três repetições, quinze acessos de mamona. Os caracteres avaliados foram altura da planta, altura do caule, número de internódios, diâmetro do caule, número de cachos, estande final e peso de 100 sementes. Observou-se que houve correlação fenotípica positiva do número de internódios e altura do caule, altura do caule e altura da planta, altura da planta e diâmetro do caule e por fim entre diâmetro do caule e peso de 100 sementes. Houve também correlação ambiental positiva entre as correlações altura de caule e altura de planta, altura de planta e diâmetro do caule, altura da planta e estande final e diâmetro do caule e número de cachos, concluindo que as correlações estimadas possibilitaram conhecer as associações entre os caracteres, fornecendo importantes informações para o estabelecimento de um plano de melhoramento genético da mamona, a partir dos acessos avaliados.

One of the great current challenges of agricultural research is the production of improved castor bean cultivars, with genetic stability, high quality and high yielding potential. The objective this work was to estimate genotypic, phenotypic and environmental correlations among traits of the castor bean plant to make the characterization of the accessions easy. They were evaluated in Lavras, MG, Brazil, in a randomized block design with three replicates, fifteen castor bean accessions. The traits evaluated were: plant height, stem height, number of nodes, stem diameter, final number of clusters, stand and 100-seed weight. It was observed that there was a positive phenotypic correlation of the node number and stem height, stem height and plant height, plant height and stem diameter and at last between stem diameter and 100-seed weight. There was also a positive environmental correlation among the correlations stem height and plant height, plant height and stem diameter, plant height and final stand and stem diameter and number of clusters, concluding that the estimated correlations make it possible to know the associations among the traits, giving important information to the establishment of a genetic improvement plan of castor bean from the accessions evaluated.

O objetivo do trabalho foi verificar o efeito de tratamentos inseticidas, na produção e no controle da disseminação de vírus por afídeos vetores e o teor de resíduos observados nos tubérculos submetidos a esses tratamentos. Foram empregadas as cultivares, Ágata e Emeraude com Potato vírus Y. O modelo utilizado foi o de blocos inteiramente casualizados, com 12 tratamentos e 4 repetições, sendo: 1) pulverização semanal (PS), com a última aos 55 dias após o plantio (DAP); 2) PS com a última aos 69 DAP; 3) PS, com a última aos 69 DAP + aplicação de Cabrio Top; 4) pulverização a cada cinco dias, sendo a última aos 69 DAP; 5) PS sendo a última aos 80 DAP e 6) controle, sem pulverização, todos combinados com dois tratamentos de sulco (Imidacloprid e Phorate). Observou-se que a maioria dos tratamentos não impediu a disseminação dos vírus.

The objective the work was to investigate the effect of insecticide treatments on virus spread and in potato yield, as well as to evaluate the residue value of the insecticides employed in the tubers subjected to these treatments. The experiment was carried out with two cultivars in randomized blocks with 40 tubers, 4 replications and 12 treatments, as follows: 1) insecticide spraying (SI) on leaves once a week, with the last application at 55 days after planting (DAP); 2) SI on leaves once a week, with the last application at 69 DAP; 3) SI on leaves once a week, with the last application at 69 DAP + application of Cabrio Top; 4) SI on leaves every five days, with the last application at 69 DAP; 5) SI on leaves once a week, with the last application at 80 DAP; and 6) control, with no insecticides after plant emergence; and all of them combined with 2 soil treatments (Imidacloprid and Phorate). Those results show that the application of insecticides is useless when the potato seed has a high PVY incidence.

O objetivo deste trabalho foi avaliar a capacidade combinatória de linhagens de tomateiro com hábito de crescimento determinado, com resistência múltipla a espécies dos gêneros Begomovirus e Tospovirus, e identificar combinações híbridas superiores. O experimento foi realizado em casa de vegetação, com 14 híbridos obtidos do cruzamento de sete linhagens femininas (grupo I) com duas linhagens masculinas (grupo II), em um dialelo parcial. As seguintes características agronômicas foram avaliadas: produção total, produção precoce, massa média de frutos, formato, firmeza inicial e firmeza na meia-vida. As linhagens genitoras TOM-680 e TOM-682, do grupo I, se destacaram por exibir as maiores estimativas de capacidade geral de combinação (CGC) quanto às características produção total, produção precoce e massa média de frutos, enquanto a linhagem TOM-585 se destacou quanto aos maiores valores de produção total e massa média de frutos. No grupo II, a linhagem TOM-698 apresentou estimativas superiores de CGC para as características de produção total, produção precoce, massa média dos frutos e firmeza inicial dos frutos. O híbrido TOM-682xTOM-698 apresenta as maiores estimativas de capacidade geral e específica de combinação para produção total, produção precoce e meia-vida da firmeza, e é o genótipo mais promissor entre os materiais testados.

The objective of this work was to evaluate the combining ability of determinate-growth-habit tomato inbred lines with multiple resistance to Tospovirus and Begomovirus species, ant to identify superior hybrid combinations. The experiment was carried out in greenhouse, with 14 hybrids obtained from crosses of seven lines of the group I (female parents) with two lines of the group II (male parent), in a partial diallel. The following agronomical traits were assessed: total production, early production, mean fruit mass, shape, initial firmness and half life firmness. The parental lines TOM-680 and TOM-682, from group I, stand out with the largest general combining ability (GCA) concerning total production, early production and average fruit mass, while line TOM-585 stood out as to higher values of total production and average fruit mass. In group II, TOM-698 showed higher estimates of GCA as to total production, early production, average fruit mass and initial consistence of the fruits. The hybrid TOM-682xTOM-698 had the highest estimate of general and specific combining ability to total production, early production and average fruit mass, and it is the most promising genotype among the materials tested.

A alface é uma espécie cujas plantas possuem grande variabilidade no que diz respeito à forma, cor e textura das folhas, caracterizando diferentes tipos comerciais. O grupo folhas lisas ainda se mantém como um dos mais consumidos. A caracterização do tipo de folha é essencial no desenvolvimento de um programa de melhoramento, principalmente, quando a população segregante é oriunda de parentais contrastantes para o caráter. Além disso, a maior parte das cultivares utilizada é sensível ao calor, emitindo a haste floral precocemente. Assim, o objetivo deste trabalho foi avaliar características comercias de progênies F4 de alface e a sua tolerância ao calor, visando obter cultivares com folha lisa tolerantes ao florescimento precoce, resistentes aos nematóides e ao LMV. Avaliaram-se 22 progênies F4 originadas do cruzamento envolvendo as cultivares 'Regina 71' e 'Salinas 88', previamente selecionadas para tolerância ao calor, resistência aos nematóides das galhas e ao LMV (lettuce mosaic virus). O delineamento foi em blocos casualizados, com quatro repetições. Foram avaliados os tipos de limbo e borda foliares, formação de cabeça e número de dias para a primeira antese. Dentre as 22 progênies avaliadas, três mostraram-se mais promissoras à obtenção de linhagens de alface de folhas lisas resistentes ao calor, nematóides das galhas e ao LMV.

The lettuce is a plant that features great variability in form, color and texture. The butterleaf variety had remained one of the most consumed lettuce types. The evaluation of leaf type for commercial characters is essential for the development of any improvement program, especially when the parents are divergent types. Furthermore, most cultivars are susceptible to heat. Thus, the objective of the present work was to evaluate F4 progenies of butterleaf lettuce, aiming to select new genotypes for nematode resistance, tolerance to heat and LMV. Twenty-two F3:4 progenies were originated from crosses involving the 'Regina 71' and 'Salinas 88' cultivars, previously selected for heat tolerance, nematode resistance and LMV (lettuce mosaic virus). The experiment was carried out in a randomized block design, with four replications. The limb, edge, head formation and the number of days until flowering were evaluated. Among the 22 evaluated progenies, three are butterleaf and may lead to new lettuce lines resistant to root-knot nematodes, heat and LMV.

O objetivo deste trabalho foi selecionar famílias F4 de alface, oriundas do cruzamento entre as cultivares Verônica e Salinas 88, para o cultivo no verão, com relação ao tipo de folha, e à resistência ao Lettuce mosaic virus (LMV) e ao nematóide-das-galhas Meloidogyne javanica. Primeiramente, avaliaram-se a coloração da folha, tipos de borda e limbo foliares, além da tolerância ao calor no campo, em blocos ao acaso compostos pelas 15 famílias F4 previamente selecionadas, pelas cultivares parentais e pela cultivar testemunha Regina 71 (folhas lisas e tolerante ao calor), com cinco repetições e oito plantas por parcela. Na segunda etapa, as famílias foram avaliadas quanto à resistência ao LMV e ao nematóide-das-galhas, em bandejas de 128 células acondicionadas em estufa. As médias das notas atribuídas a cada família foram comparadas às médias de cada cultivar parental pelo teste de Dunnet (5%). A família AFX007B-140-21, homozigota resistente aos nematóides e ao LMV e, também, tolerante ao calor, foi a mais promissora. O cruzamento entre uma cultivar de folhas crespas e soltas com uma de folhas crespas e repolhuda, pode originar linhagens promissoras tanto de folhas crespas quanto de folhas lisas.

The aim of this work was to select F4 lettuce families, derived from the cross 'Veronica' x 'Salinas 88 ', for summer cropping, type of leaves, and for resistance to Meloidogyne javanica and to Lettuce mosaic virus (LMV). First, evaluations were made for leaf colour, leaf limb, border type, and heat tolerance in the field, in a complete blocks desing, in 15 F4 families previously selected, parent cultivars and, as control, the cultivar Regina 71 (butterleaf and tolerant to heat). Five replicates and eight plants per plot were used. As second step, the families were evaluated in greenhouse, in 128-cell expanded polystyrene trays, for resistance to LMV and root-knot nematodes. Score means of each family were compared to the means of each parental cultivar by Dunnett test at 5% probability. Family AFX007B-140-21, homozygous for root-knot nematodes, for LMV and heat tolerant, was the most promising. The cross between crisp and butter leaf cultivars can originate promising lineages both with crisp and butter leaves.