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Made available in DSpace on 2022-05-01T09:30:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 During the winter, there is a high occurrence of downy mildew on lettuce caused by Bremia lactucae. This oomycete shows variability in virulence, so understanding the genetic structure of the pathogen population becomes essential for obtaining resistant cultivars. Thus, the objective of this study was to determine sexual compatibility in Brazilian populations of B. lactucae and investigate the occurrence of sexual reproduction of the pathogen on lettuce (Lactuca sativa) and prickly lettuce (Lactuca serriola). Leaf samples were collected in 33 municipalities in seven Brazilian states. The virulence structure of the populations was monitored using the EU-C sextet code. B. lactucae populations from the states of São Paulo, Paraná, Rio de Janeiro, and Rio Grande do Sul shared six of the 15 virulence factors evaluated. Twenty-five virulence phenotypes (v-phenotypes) were found, with the sextet codes 31-00-02, 31-16-02, 31-24-02, and 31-01-02 being more frequent. The predominance of some v- phenotypes indicates that clonal reproduction is still the main form of B. lactucae propagation. The genes and resistance factors of the cultivars Argelès (Dm38), Balesta, and Bartoli are recommended as suitable sources of lettuce resistance in Brazil. Natural occurrence of oospores was detected in most sampled locations, in lettuce and prickly lettuce plants. Virulence variability of Brazilian isolates is the result of the pathogen's ability to reproduce both sexually and asexually, with a prevalence of homothallic isolates; although the majority were of the predominant B2 mating type, there was a high incidence of predominant B1 in addition to B1 = B2. Department of Agricultural Production Sciences São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences, SP Department of Plant Pathology Gulf Coast Research and Education Center University of Florida Research Department – Lettuce Breeding Agristar do Brasil, SP Department of Botany Faculty of Science Palacký University in Olomouc Department of Agricultural Production Sciences São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences, SP

Made available in DSpace on 2021-06-25T10:16:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Lettuce downy mildew caused by Bremia lactucae is one of the main diseases in high humidity and low temperature conditions. The identification of virulence factors appearing in the pathogen population could help improve breeding programs against this disease. This study aimed to monitor and evaluate virulence dynamic changes in B. lactucae virulence among two Brazilian regions to recommend resistance genes for breeding programs. Isolates from São Paulo, Rio Grande do Sul, and Paraná states were assessed using the sextet code EU-C composed by 16 Lactuca spp. genotypes, between 2015 and 2016. To understand the population dynamics, the frequencies of virulence phenotypes and factors and the virulence complexity per isolate (Ci), phenotype (Cp), and Gleason (Ig), indexes were calculated. B. lactucae virulence from Paraná, Rio Grande do Sul and São Paulo were similar and shared nine out of the 15 evaluated virulence factors. In total, 90 isolates were analyzed, and 27 virulence phenotypes were found. The most frequent sextet codes were 31–00-00, 31–00-02, 31–01-00, and 31–01-02. The genes or resistance factors present in ‘Argelès’ (Dm38), ‘Balesta’, and ‘Bartoli’ could be used as sources of resistance by Brazilian lettuce breeders. Department of Crop Production School of Agricultural and Veterinarian Sciences UNESP- São Paulo State University (Unesp) Gulf Coast Research and Education Center University of Florida Department of Plant Pathology School of Agricultural and Veterinarian UNESP- São Paulo State University (Unesp) Department of Crop Production School of Agricultural and Veterinarian Sciences UNESP- São Paulo State University (Unesp) Department of Plant Pathology School of Agricultural and Veterinarian UNESP- São Paulo State University (Unesp)

Made available in DSpace on 2022-05-01T00:03:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) For the lettuce crop, there is no specific or standard methodology to evaluate genotype resistance of lettuce against downy mildew. Therefore, the aim of this work was to compare three methodologies for the identification of resistance to downy mildew. The experiment was carried out at Universidade Federal de Uberlândia, Monte Carmelo Campus between 2017 and 2018. The statistical method used was a completely randomized design with 12 treatments (cultivar Solaris, used as a control; and 11 genotypes of lettuce F5: 6: UFU-Crespa 75 # 2, UFU-Crespa 189 # 2, UFU-Crespa 206 # 1, UFU-Lisa 66 # 3, UFU-Lisa 66 # 7, UFU-Lisa 215 # 3, UFU-Lisa 215 # 6, UFU-Lisa 215 # 10, UFU-Lisa 215 # 12, UFU-Lisa 215 # 13, UFU-Lisa 215 # 14) and four replications. The seeding of genotypes was carried out in transparent boxes and after 15 days the inoculation was performed using a spore suspension (1x104 sporangia/ml) and sterile deionized water for the controls. The disease progression was assessed by three methods: Mesquita, Dickinson & Crute and Horsfall & Barrat. The data were standardized and submitted to the univariate analysis of variance by the F test and multivariate analyzes. The univariate clustering results allowed the separation of the genotypes into two distinct resistance groups for the Dickinson & Crute and Mesquita methods. In the multivariate analysis, more formation of groups among genotypes with different levels of resistance to downy mildew in the Mesquita method was observed. The methodology proposed by Mesquita was more efficient in discriminating genotypes with different levels of resistance to downy mildew, separating them in a larger number of groups. Instituto de Ciências Agrárias Universidade Federal de Uberlândia, Campus de Monte Carmelo Gulf Coast Research and Education Center University of Florida Departamento de Produção Vegetal Universidade Estadual Paulista 'Júlio de Mesquita Filho' Departamento de Produção Vegetal Universidade Estadual Paulista 'Júlio de Mesquita Filho'

The objective of this work was to estimate the stability and genotypic adaptability of advanced lines and cultivars of curled green-leaf lettuce (Lactuca sativa), in different growing environments and seasons, using the REML/Blup mixed model. Ten genotypes, seven cropping environments, and two growing seasons were studied in 2015. Plant yield traits were evaluated, and data were subjected to the Selegen-REML/Blup software. Genotype stability and adaptability were analyzed using the harmonic mean of genotypic values (HMGV) and the relative performance of genotypic values (RPGV), respectively. The harmonic mean of RPGV (HMRPGV) was used to simultaneously estimate the stability, adaptability, and yield of breeding lines or cultivars. Considering the combined analysis of the two seasons for the set of traits, the lines L6, L7, and L8 were selected as promising ones and recommended for planting. The breeding lines selected for all season exhibit good yield and are considered superior to the commercial cultivars Vanda and Vera. Resumo: O objetivo deste trabalho foi estimar a estabilidade e a adaptabilidade genotípica de linhagens avançadas e cultivares de alface-crespa (Lactuca sativa), em diferentes sistemas de cultivos e épocas, pelo modelo misto REML/Blup. Foram avaliados dez genótipos de alface, sete sistemas de cultivo e duas épocas, em 2015. Avaliaram-se os caracteres de produção das plantas, e os dados foram submetidos ao programa Selegen-REML/Blup. A estabilidade e a adaptabilidade genotípica foram analisadas pelos métodos da média harmônica dos valores genotípicos (MHVG) e do desempenho relativo dos valores genotípicos (PRVG), respectivamente. A média harmônica do PRVG (MHPRVG) foi utilizada para estimar simultaneamente a estabilidade, a adaptabilidade e a produtividade das linhagens e das cultivares. Ao se considerar a análise conjunta das duas épocas para o conjunto dos caracteres, as linhagens L6, L7 e L8 foram selecionadas como promissoras e recomendadas para plantio. As linhagens selecionadas para todas as épocas apresentam bons rendimentos e são consideradas superiores às cultivares comerciais Vanda e Vera.

Made available in DSpace on 2021-07-14T10:53:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2017. Added 1 bitstream(s) on 2021-07-14T11:40:43Z : No. of bitstreams: 1 S1983-40632017000400440.pdf: 248406 bytes, checksum: 1732a3392a61a00c38a4cd31105ca06b (MD5) O uso de resistência genética é um dos métodos mais adequados para o controle de oídio das cucurbitáceas em melão, causado por Podosphaera xanthii ou Golovinomyces orontii. Contudo, muitas raças desses patógenos têm sido descobertas, o que pode comprometer a eficácia desse método. Fazem-se, então, necessários o constante monitoramento de raças de oídio e a busca por novas fontes de resistência. Objetivou-se identificar em nível de raça uma população natural de oídio das cucurbitáceas em casa-de-vegetação, bem como avaliar a reação de genótipos locais e exóticos de meloeiro à raça identificada. A identificação da raça foi baseada na reação de oito linhagens diferenciadoras (PI 414723, PMR 45, PMR 5, WMR 29, Edisto 47, Nantais Oblong, PI 124111 e Védrantais). Foram avaliados 59 genótipos de meloeiro, sendo 53 destes acessos de germoplasma e seis linhagens de melão rendilhado, além de duas cultivares (Louis e Fantasy). As plantas foram avaliadas com base em escala visual para lesões nas folhas. A espécie P. xanthii foi confirmada como o agente causal, pela visualização de corpos de fibrosina nos conídios e pela resistência da abóbora d’água (Benincasa hispida). A raça 4 foi identificada pela primeira vez no estado de São Paulo. Os genótipos A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 e Solarking mostraram-se resistentes à raça 4. Genetic resistance is one of the most suitable strategies to control cucurbit powdery mildew (CPM) on melon, incited by Podosphaera xanthii or Golovinomyces orontii. However, many races of these pathogens have been reported worldwide in recent years, what may compromise the effectiveness of this method. Thus, annual surveys of CPM races and the screening of germplasm for new sources of genetic resistance provide a vital support to melon breeding programs. This study aimed at identifying a natural population of CPM race under greenhouse conditions, as well as evaluating the reaction of local and exotic melon germplasm for CPM-resistance. CPM race identity was based on the reaction of eight race differentials: Védrantais, Nantais Oblong, PMR 45, PMR 5, WMR 29, Edisto 47, PI 414723 and PI 124111. Fifty-nine melon genotypes were evaluated, 53 of them being germplasm accessions, and six net melon elite-inbred lines, besides two net melon-type cultivars (Louis and Fantasy). Plants were evaluated using a visual scale for leaf lesions. The causal pathogen was confirmed to be P. xanthii, based on the presence of fibrosin bodies in conidia and the complete resistance response of winter melon (Benincasa hispida). Race 4 was identified for the first time in the São Paulo state, Brazil. Genotypes A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 and Solarking showed to be resistant to the race 4. Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agrárias e Veterinárias United States Department of Agriculture, Agricultural Research Service Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agrárias e Veterinárias

The okra (Abelmoschus esculentus L. Moench) is one of the most important vegetables in the world and is a popular food item in many tropical and subtropical countries. Besides its cultivation for fresh consumption, okra also has potential industrial uses. Nonetheless, pests and diseases remain the most damaging factors affecting its crop yield. Among these, root-knot nematodes are the main pests limiting okra production. This study aimed to determine the responses of plant species of the Malvaceae family to Meloidogyne incognita and M. enterolobii root-knot nematodes, and to also assess the compatibility of the same with the okra commercial 'Colhe Bem IAC'. Resistance was evaluated using the reproduction factor in two commercial okra cultivars ('Colhe Bem IAC' and 'Santa Cruz 47'), five cotton (Gossypium hirsutum L.) plant genotypes (PRO 277, IAC 29-233, PR 136, IAC 24, and IAC 03-979), and vinagreira (Hibiscus sabdariffa L.) Other resistance-related traits measured were the percentage of healing, plant height, root length, rootstock stem diameter, scion stem diameter, number of leaves, total fresh weight, and fresh weight of the scion, rootstock, and root parts. While the cotton and vinagreira genotypes tested were resistant to both species of nematodes, okra cultivars were not. The okra, however, showed successful adaptation to grafting, which may offer an important physical resistance against attacks by root-knot nematodes, while vinagreira showed the greatest potential for use as rootstock for protecting okra crops.

Made available in DSpace on 2022-04-29T07:32:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-23 The objective of this study was to evaluate the influence of tray type and substrate on the initial development of the mini watermelon hybrid 'Ki Kodama'. The following treatments were compared: Three types of tray, 128, 200 and 288 cells, and three types of substrate, Bioplant HT, Biofibra, Bioflora. Treatments were factorially combined. Evaluations were performed 30 days after sowing, and the following parameters were determined: fresh and dry weights of shoot, fresh and dry weights of root, seedling height, number of leaves, root length, stem and root diameters, and leaf and root areas. There was a significant interaction between tray and substrate treatments for fresh and dry weights of shoot and root, stem diameter, and leaf and root areas. For the factor tray, only the root diameter differed, and 128-cell trays showed better performance, while for substrate, height, root length and number of leaves showed significant differences, with Bioflora providing better development of seedlings. For the other parameters, the best performance was observed in 288-cell trays filled with Bioplant HT. The results obtained can be explained because the volume occupied by substrate in each cell varies, which causes root and leaf development also to differ. Thus, for the conditions under which the experiment was conducted, seedlings of mini watermelon 'Ki Kodama' should be grown in 128 or 288 cell trays, filled with the commercial substrate Bioplant Prata HT or Bioflora. Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista

Made available in DSpace on 2022-04-29T07:32:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-23 Reusing the substrate in subsequent crops has been proposed due to several advantages, especially economic and environmental ones. Furthermore, the electrical conductivity of the nutrient solution can directly influence the nutrient content present in the substrate, especially when it is reused, thus interfering with absorption by plants. In this way, the present study aimed to determine the feasibility of reusing the substrate and determine the optimal concentration of the nutrient solution in tomato cultivation. The experiment was conducted in a greenhouse at the Department of Vegetable Crops and Aromatic Medicinal Plants, belonging to FCAV-UNESP. The 'Paronset' hybrid was cultivated in pots containing coconut husk fiber as substrate. The nutrient solution was evaluated at five concentrations, namely 25, 50, 100 (original solution), 150 and 200% of recommended solution, and the substrate at two usage levels (new and reused). Fertigation was performed by dripping with nutrient solution as recommended. The characteristics evaluated were: Production per plant, yield, number of fruits per plant, average fruit weight, soluble solids, and transverse and longitudinal fruit diameter. There was no interaction between the reuse of the substrate and nutrient solution concentration; moreover, there was no difference between the characteristics evaluated for all treatments. Under the conditions of this study, the reuse of the substrate is recommended, at least once, and the use of nutrient solution at a concentration of 25% of the original for the cultivation of 'Paronset' tomato hybrid. Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Solos E Adubos Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Solos E Adubos Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista