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To assess the influence of melon genotypes on the feeding and oviposition preferences and survival of L. sativae immatures, a study was carried out by offering 21 melon genotypes (no-choice tests). Among the genotypes, 18 were the least preferred by L. sativae for oviposition, as demonstrated by the reduced numbers of eggs laid on the leaves, while 7 were least preferred for feeding, as demonstrated by the reduced feeding punctures inflicted on the leaves. Genotypes CNPH 06–1047-333 and CNPH 06–1047-341 exhibited strong antibiosis resistance, as confirmed by the occurrence of 100% larval mortality. Scanning electron microscopy revealed that for both abaxial and adaxial surfaces of the leaves, the genotypes CNPH 06–1047-343, CNPH 06–1047-341 and CNPH 11–1071-43 had a lower density of trichomes and higher thickness of leaf epidermis when compared to the susceptible genotype. We also found a positive and significant correlation between the number of trichomes and the number of eggs of L. sativae on the abaxial and adaxial surfaces and with the feeding punctures on the adaxial surface of the melon leaves. On the other hand, the thickness of the leaf epidermis was negatively correlated with the number of insect eggs on the abaxial and adaxial surfaces and with the feeding punctures on the adaxial surface of the leaves. Antixenosis (feeding and oviposition preferences) on melon plants towards L. sativae is associated with a lower number of trichomes and to a higher thickness of the epidermis of leaves. Causes implicated to antibiosis should be further investigated.

Foliar anthracnose is one of the main diseases of onion (Allium cepa L.) under tropical and subtropical conditions. Thus far, only Colletotrichum gloeosporioides has been reported as the causal agent of this disease in Brazil. However, there are no extensive studies characterizing Colletotrichum isolates associated with onion anthracnose in the country. Here, 38 Colletotrichum isolates obtained from onion plants displaying foliar anthracnose across major Brazilian onion-producing regions were characterized using morphometric and molecular information. The Bayesian and Maximum Liklihood methods were used for an initial analysis of the β-tubulin gene (tub2) sequences of all isolates, resulting in the discrimination of nine haplotypes. Three haplotypes grouped with the reference species of the C. acutatum complex and six with the C. gloeosporioides complex. Sequences of either the glyceraldehyde-3-phosphate dehydrogenase (gapdh), actin (act), and calmodulin genes or the intergenic spacer (IGS) region between DNA lyase (apn2) gene and the mating-type mat1–2-1 locus were used to characterize a subset of isolates representing these nine distinct tub2 gene haplotypes. These analyses revealed five anthracnose-inducing Colletotrichum species, including three members of the C. acutatum species complex (C. nymphaeae, C. scovillei, and C. tamarilloi) and two of the C. gloeosporioides species complex (C. fructicola and C. theobromicola). Bioassays confirmed that all these Colletotrichum species are pathogenic to onion, inducing typical anthracnose symptoms on bulbs and leaves. Twenty-six out of 38 isolates were identified as C. theobromicola, indicating this fungus as the prevalent anthracnose pathogen under Brazilian conditions. This Colletotrichum species diversity will affect anthracnose management strategies, including chemical and cultural control as well as the identification and deployment of onion cultivars with species-specific and/or wide-spectrum tolerance/resistance.

The aim of this research was to prospect genetic resistant sources to root-knot-nematode in Cucurbitaceae accessions. Two assays were conducted, the first to evaluate the resistance to root-knot nematode, M. incognita race 1 in accessions of Lagenaria vulgaris; Sicana odorifera; Cucurbita facifolia; Luffa sp.; Citrullus lanatus cv. Citroides; Lagenaria vulgaris; Cucurbita moschata; Cucurbita moschata x Cucurbita maxima; Cucumis melo and Cucumis metuliferus. The second to evaluate the reaction to nematode M. incognita race 1, M. javanica and M. enterolobii of the three accessions of Cucumis metuliferus (‘Kino’) considered resistant to M. incognita race 1 in the first experiment. The assays were carried out in a greenhouse at Embrapa Hortaliças in a completely randomized design with six replications. The seedlings in pots were inoculated with 5000 eggs and juveniles of 2nd stage (J2) of each Meloidogyne species alone. Fifty-three and eighty-four days after inoculation, respectively in both experiments, the plants were evaluated for egg mass index (IMO), gall index (IG), number of eggs per gram of root (NEGR) and reproduction factor (RF). The melon Cucumis metuliferus known as ‘Kino’ was identified as genetic source of resistance to root-knot nematodes and can be explored in breeding program as resistant rootstock. RESUMO O objetivo desse trabalho foi prospectar fontes de resistência aos nematoide-das-galhas em acessos de cucurbitáceas. Foram realizados dois experimentos, o primeiro para avaliar a resistência ao nematoide-das-galhas, M. incognita raça 1 em acessos das espécies Lagenaria vulgaris; Sicana odorífera; Cucurbita facifolia; Luffa sp.; Citrullus lanatus cv. Citroides; Lagenaria vulgaris; Cucurbita moschata; Cucurbita moschata x Cucurbita máxima; Cucumis melo e Cucumis metuliferus. O segundo para avaliar a reação aos nematoides M. incognita raça 1, M. javanica e M. enterolobii em três acessos de Cucumis metuliferus (‘Kino’) considerados resistentes a M. incognita raça 1 no primeiro experimento. Os experimentos foram conduzidos em casa-de-vegetação na Embrapa Hortaliças, em delineamento inteiramente casualizado com seis repetições. As mudas mantidas em vasos foram inoculadas com 5000 ovos e eventuais juvenis de 2º estádio (J2) das espécies de Meloidogyne, isoladamente. Cinquenta e três, e oitenta e quatro dias após a inoculação, para os dois experimentos respectivamente, as plantas foram avaliadas quanto ao índice de massas de ovos (IMO), índice de galhas (IG), número de ovos por grama de raiz (NEGR) e fator de reprodução (FR). Verificou-se que a espécie de melão conhecida como ‘Kino’, é um recurso genético que pode ser explorado para a resistência a M. incognita raça 1, M. javanica e M. enterolobii com potencial uso como porta enxerto resistente.

Line A915.34.01.08 is a new source of resistance to Liriomyza sativae in melon. It was obtained by the genealogical method from a heterozygous plant with antibiosis type of resistance found within the accession CNPH 00-915. This line allows making introgression of this resistance in melon lines to develop commercial hybrids.

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.

This study aimed to evaluate onion accessions regarding their resistance to Thrips tabaci Lindeman, in order to enable the development of cultivars that are resistant to this pest. The experiments ...

Fusarium oxysporum f. sp. lactucae (FOLac) is responsible for significant economic losses across major lettuce-producing regions around the world. Thus far, only FOLac race 1 isolates have been reported associated with Fusarium wilt outbreaks in Brazil. The most sustainable strategy for disease control is the pyramidization of race-specific resistance factors in lettuce cultivars. The loose-leafy cultivar ‘Vanda’ was found as one of the most promising sources of resistance to FOLac race 1. The genetic basis of this resistance was determined by analyzing the reaction to this pathogen of segregating populations derived from the cross ‘Gisele’ (susceptible) × ‘Vanda’ (pollen donor). A single molecular marker-genotyped F1 hybrid plant was selfed and individual plants of a segregating F2 population as well as 63 families F2:F3 were inoculated with a FOLac race 1 isolate by using the root-dipping method (3 × 106 conidia/ml). Our results confirmed the high levels of resistance of ‘Vanda’ even under very harsh experimental conditions. Overall, the reaction of the F1 plants and the segregating patterns of the F2 population (n = 82) and of the F2:F3 families (n = 838 plants) fit a single dominant gene/locus model. However, the phenotypic expression of resistance might suffer effects of additional genetic factor(s) (e.g., locus dosage, minor modifying genes, and incomplete penetrance). Notwithstanding, the high levels of FOLac race 1 resistance and its relatively simple genetic control makes ‘Vanda’ a major germplasm source for lettuce-breeding programs aiming to incorporate this trait in a wide array of elite lines from distinct varietal groups.

A mosca minadora Liriomyza sativae Blanchard é um inseto polífago, considerada umas das principais pragas do meloeiro na região semiárida brasileira. A definição de um método de amostragem é fundamental para a implementação de um programa de manejo integrado dessa praga. Sendo assim, o presente trabalho teve como objetivo definir a folha amostral para larvas de L. sativae na cultura do meloeiro. O estudo foi desenvolvido em duas áreas comerciais de melão no município de Juazeiro (BA). Após a emergência das plântulas, semanalmente realizou-se o monitoramento para acompanhar a ocorrência de mosca minadora até o término do ciclo. O ramo principal era observado para a presença de larvas de L. sativae, com a constatação, a folha era destacada e identificada a sua posição a partir da base do ramo. Sob microscópio óptico (40x) com luz por transmissão foi contabilizado o número de larvas vivas por folha. Foram realizadas sete coletas semanais a partir do décimo quinto dia após o plantio. Verificou-se que, de acordo com a fenologia da planta, difere a folha a ser amostrada. Para o monitoramento da mosca minadora deve-se amostrar as folhas da base para o ápice do ramo principal do meloeiro. Para as semanas 1, 2, 3, 4, 5 e 6 após o plantio, as folhas a serem amostradas devem ser a 1, 2 ou 3, 4, 6, 9, 14 e 20, respectivamente.

Brown onions of the ‘Valenciana’ type are not available for short-day growing conditions in the Northeast of Brazil. The goal of this study was to estimate parameters of adaptability and stability in order to release ‘Valenciana’ onion cultivars in the Northeast of Brazil. Eight populations of onions derived from a cross between ‘Baia population’ בValcatorce INTA’ and improved by recurrent selection were associated with six commercial onion cultivars, included as controls; they were evaluated in five experiments carried out in the municipalities of Petrolina, Pernambuco, Juazeiro, Bahia and Belem do Sao Francisco, Pernambuco. The experimental design was a randomized block design with three replications. Total and commercial bulb productions were evaluated for adaptability and stability parameters according to the methodologies of Eberhart and Russell, Lin and Binns and Main Effects and Multiplicative Interaction (AMMI). Significant genotype × environment interaction was observed for the two analysed variables. Eberhart & Russell and AMMI showed similar results for the overall cultivars, while some discrepancies were observed under the Lin & Binns method. The three methodologies produced concordant results for the ‘Valenciana’ onion types. The 25CA10 and T811CR13B’Valenciana’populations demonstrated broad adaptability and stability, associated with bulb production close to some cultivars and the commercial hybrid, and will be protected and released as new cultivars in the Northeast region of Brazil.

RESUMO: A mancha púrpura é uma das doenças mais limitantes da cebola, e a resistência genética é forma de controle mais viável da doença. O objetivo deste trabalho foi avaliar a reação de genótipos de cebola a alternaria porri em campo. Foram avaliados 64 genótipos (cultivares, populações e linhagens do programa de melhoramento da embrapa) em sistema convencional de cultivo. Utilizou-se como testemunha resistente a população cnph 6342 e como suscetível a linhagem macho-fértil 420. A cultura foi implantada pelo método de semeadura direta com população de 500 mil plantas por hectare. Foi utilizado o delineamento de blocos ao acaso com cinco repetições. As parcelas foram constituídas de seis fileiras no sentido longitudinal do canteiro, espaçadas de 15 cm (área total de 0,9 m²). A doença ocorreu de forma natural no campo e, a severidade foi avaliada em dez plantas por parcela aos 80, 110 e 140 dias após a semeadura. A produtividade e a massa média de bulbos comerciais (diâmetro ≥35 mm) foram avaliadas em apenas 45 genótipos, os quais exibiram adaptação às condições de clima local e bulbificaram adequadamente. 'crioula mercosul', '446', 'bola precoce', 'juporanga l2', 'caeté', 'rainha', 'dourada', 'juporanga l7', 'cnph 6342', 'crioula alto vale' e 'roxa do barreiro' apresentaram maior resistência ao patógeno, com áreas abaixo da curva de progresso da severidade da doença (aacpsd) inferiores a 437,33, enquanto a linhagem macho-fértil 420 apresentou aacpsd de 1.177,94. Os genótipos 'brs 367' e 'shinju', por sua vez, associaram alta produtividade de bulbos comerciais e moderada resistência à doença, com produtividades superiores a 43,9 t/ha e aacpsd inferiores a 567,28, sendo considerados os mais tolerantes à mancha púrpura.

The need to adapt agricultural crops to climate change and to develop more sustainable cultivation systems has been a major challenge for agriculture. In this study the effects of soil conservation practices were evaluated on production aspects of melon (Cucumis melo), cultivar BRS Araguaia, cultivated in a greenhouse under soil and climatic conditions of the Brazilian Cerrado. The adopted experimental design was of randomized blocks with three treatments (soil managements) and six replicates. We evaluated the following soil management systems: no-tillage (PD), minimum tillage (CM) and conventional tillage (PC) in two cycles. Increases in commercial productivity and average number of marketable fruits were observed for PD (61.5 and 61.2 t/ha; 56,000 and 44,300 fruits/ha in the first and second cycles, respectively) and CM (59.7 and 57.5 t/ha; 55,700 and 42,400 fruits/ha in the first and second cycles, respectively). No effects of management systems on fruit quality were observed. PD and CM were effective in increasing the melon production under evaluated conditions. RESUMO A necessidade de adaptação de cultivos agrícolas às mudanças climáticas, aliada à necessidade de desenvolvimento de cultivos mais sustentáveis constitui um grande desafio para a agricultura. O presente trabalho teve como objetivo avaliar os efeitos de sistemas de manejo de solo conservacionistas sobre aspectos produtivos de melão amarelo (Cucumis melo), cultivar BRS Araguaia, cultivado em ambiente protegido em condições edafoclimáticas do Cerrado brasileiro. O experimento foi conduzido em delineamento de blocos ao acaso, com três tratamentos (manejos de solo) e seis repetições. Foram avaliados os seguintes sistemas de manejo de solo: plantio direto na palha (PD), cultivo mínimo (CM) e plantio convencional (PC), em dois ciclos culturais. Foram observados incrementos na produtividade e no número médio de frutos produzidos quando do uso do PD (61,5 e 61,2 t/ha no primeiro e segundo ciclo, respectivamente) e do CM (59,7 e 57,5 t/ha no primeiro e segundo ciclo, respectivamente). Nenhum efeito dos sistemas de manejo sobre a qualidade dos frutos foi observado. O PD e o CM foram eficientes em aumentar a produção do melão amarelo nas condições avaliadas.

The aim of this research was to prospect genetic resistant sources to root-knot-nematode in Cucurbitaceae accessions. Made available in DSpace on 2019-11-08T18:16:40Z (GMT). No. of bitstreams: 1 ArtigoNematodesemCucurbitaceasPinheiroetal2019.pdf: 505825 bytes, checksum: 7571cfedc76199e6e15423e22fc34c69 (MD5) Previous issue date: 2019

A cultivar, sozinha, não é garantia de sucesso de uma lavoura de cebola, mas a escolha equivocada certamente comprometerá a produção até inviabilizar a lavoura.

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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.

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Uma das principais doenças que afetam a cebola, especialmente em regiões de clima quente, Setophoma terrestris registra crescimento de incidência no Brasil, principalmente pela ausência de rotação de culturas e plantio de cultivares altamente suscetíveis. Os prejuízos, em condições ambientais favoráveis ao patógeno, podem alcançar 100%, com o consequente abandono da lavoura por conta da má qualidade dos bulbos. Evitar cultivos sucessivos, buscar cultivares resistentes/tolerantes e realizar adubação equilibrada estão entre as medidas para prevenir e minimizar o problema.