Abstract The objective of this work was to evaluate the performance of okra grafted onto Hibiscus spp. in the presence and absence of three root knot nematode species. The experimental design was completely randomized in a 4x4 factorial arrangement with ten replicates. The first factor consisted of the following four rootstocks: kenaf (Hibiscus cannabinus), false roselle (Hibiscus acetosella), self-grafted, and non-grafted. The second factor was the inoculation of 5,000 eggs and second-stage juveniles of Meloidogyne incognita, Meloidogyne javanica, and Meloidogyne enterolobii in okra plants, plus an uninoculated control. Vegetative development, agronomic performance, and nematode reproduction were evaluated. The grafting of okra onto Hibiscus spp. in the presence of root-knot nematodes provided a greater plant height, scion length, fresh shoot mass, number of fruits, and yield, when compared with self-grafted and non-grafted plants. The averages of the root-knot nematode reproduction factor were low in the plants grafted onto Hibiscus spp., indicating that grafting in the presence of root-knot nematodes is capable of maintaining okra vegetative development and yield.

Resumo O objetivo deste trabalho foi avaliar o desempenho de quiabo enxertado em Hibiscus spp. na presença e na ausência de três espécies de nematoides-de-galha. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial 4x4, com dez repetições. O primeiro fator foi constituído pelos quatro seguintes porta-enxertos: vinagreira-roxa (Hibiscus cannabinus), vinagreira-flor-de-veludo (Hibiscus acetosella), autoenxertia e pé-franco. O segundo fator foi a inoculação de 5.000 ovos e juvenis de segundo estágio de Meloidogyne incognita, Meloidogyne javanica e Meloidogyne enterolobii em plantas de quiabo, além de testemunha não inoculada. Foram avaliados desenvolvimento vegetativo, desempenho agronômico e reprodução do nematoide. A enxertia de quiabo em Hibiscus spp. na presença de nematoides proporcionou maiores altura de planta, comprimento de enxerto, massa fresca da parte aérea, número de frutos e produtividade, em comparação às plantas autoenxertadas e pé-franco. As médias do fator de reprodução dos nematoides foram baixas nas plantas enxertadas em Hibiscus spp., o que indica que a enxertia na presença de nematoides é capaz de manter o desenvolvimento vegetativo e a produção do quiabo.

RESUMO Há poucas fontes de resistência genética a nematoides-de-galha relatadas em algodoeiro, e não há cultivares no Brasil que combinem simultaneamente resistência e bons atributos agronômicos. Técnicas que possibilitem selecionar eficientemente fontes de resistência genética promissoras são necessárias. Objetivou-se identificar genótipos de algodoeiro resistentes a Meloidogyne incognita raça 3, por meio de REML/Blup. O experimento foi inteiramente casualizado, com 32 genótipos e sete repetições, em ambiente protegido. Foi utilizado o modelo estatístico 83. Foram estimados a massa de raízes, população final, fator de reprodução e índice de reprodução. A população final e o índice de reprodução apresentaram os maiores valores de variância genotípica e coeficientes de variação genética, sinalizando situação favorável à seleção de genótipos de algodão resistentes ao nematoide. A herdabilidade média do genótipo (h2mg) foi superior a 85 % para população final, fator de reprodução e índice de reprodução, abrindo a possibilidade de sucesso de seleção com base nas médias dos genótipos. Os genótipos CS8601, SA2572, Coodetec 404 e BJ 3128 são promissores para cruzamentos visando à seleção de genótipos resistentes ao nematoide.

ABSTRACT Few genetic resistance sources to root-knot nematodes are known for cotton, and there are no cultivars combining both resistance and good agronomic attributes in Brazil. Techniques that allow an efficient selection of promising sources of genetic resistance are needed. This study aimed to identify cotton genotypes resistant to Meloidogyne incognita race 3 via REML/Blup. The experiment was completely randomized, with 32 genotypes and seven replicates, in a protected environment. The statistical model 83 was used. The root weight, final population, reproduction factor and reproduction index were estimated. The final population and reproduction index presented the highest values for genotypic variance and genetic variation coefficients, indicating a favorable situation for the selection of cotton genotypes resistant to the nematode. The mean heritability (h2mg) of the genotype was higher than 85 % for the final population, reproduction factor and reproduction index, opening a possibility of selection success based on genotype means. The genotypes CS8601, SA2572, Coodetec 404 and BJ 3128 are promising for crosses aiming the selection of genotypes resistant to the nematode.

Abstract The exploration of heterosis can be an efficient alternative to increase okra yield. The partial diallel strategy optimizes resources by guiding crosses based on genetic diversity between various genotypes. This study aimed to identify potential hybrid combinations through diallel analysis in comparison with commercial cultivars. The hybrids were evaluated by means of a partial diallel scheme based on the genetic divergence of the genotypes. Fourteen hybrids and their reciprocals were evaluated in the winter and summer conditions of Jaboticabal - SP for yield, number of fruits and precocity. No line showed significant general combining ability. The reciprocal effect was not significant for the evaluated characteristics. Four hybrid combinations showed significant and positive specific combining ability for number of fruits, which were considered promising hybrids. In the winter, the experimental hybrids 1 x 8 and 3 x 8 showed superior performance compared to the commercial hybrids. No significant differences were observed in the summer.

Abstract Ethylene can change the flowering pattern of some cucurbits, favoring the emergence of female flowers. The objective was to determine the influence of doses and number of ethephon applications in sex reversal of zucchini (Cucurbita pepo L.). The experiment was conducted in a 4 x 4 factorial arrangement, plus a control (natural flowering), the first factor being the ethephon doses (125, 250, 375 and 500 mg·L-1) and the second the number of applications (1, 2, 3 and 4). Ethephon influenced the sexual expression of zucchini, but not enough to achieve complete sex reversal. The 500 mg·L-1 dose provided the largest feminization for all applications. Ethephon might be a useful tool for zucchini breeding programs.

Resumen El etileno puede cambiar el patrón de floración de algunas cucurbitáceas, lo que favorece la aparición de flores femeninas. El objetivo de este estudio fue determinar la influencia de las dosis y el número de aplicaciones de etefón en la reversión sexual de flores de calabacita (Cucurbita pepo L.). El experimento se realizó bajo un arreglo factorial 4 x 4, más un testigo (floración natural); el primer factor fue la dosis de etefón (125, 250, 375 y 500 mg·L-1), y el segundo fue el número de aplicaciones (1, 2, 3 y 4). El etefón influyó en la expresión sexual de la calabacita, pero no lo suficiente como para lograr una reversión sexual completa. La dosis de 500 mg·L-1 de etefón proporcionó la mayor feminización en todas las aplicaciones; por lo que, el etefón podría ser una herramienta útil en los programas de reproducción de calabacita.

ABSTRACT. The development of melon lines resistant to gummy stem blight (GSB) is an important strategy for decreasing losses caused by this disease. Thus, selecting the best parents for such a goal is essential. We evaluated the general (GCA) and specific (SCA) combining abilities of lines and accessions to guide the selection of the most promising parents to develop GSB-resistant lines. Six genotypes representing two groups (group I - susceptible: group II - resistant) were crossed in a partial diallel mating design. The genotypes were evaluated for disease expression using a rating scale from 0 (resistant) to 4 (susceptible). Estimates of GCA were negative and significant for the accessions PI 420145 and PI 482398, which can be suggested for crosses aimed at obtaining melon lines resistant to GSB. There is a reciprocal effect for the resistance of melon genotypes to Didymella bryoniae, especially when PI 482398, PI 420145, and PI 140471 are crossed with JAB-20. Such results indicate that maternal effects may be involved in the resistance to gummy stem blight.

Resumo: O objetivo deste trabalho foi estimar os danos causados por Meloidogyne enterolobii em quiabeiro (Abelmoschus esculentus) e verificar a confiabilidade do fator de reprodução como medição adequada para a seleção de genótipos de quiabeiro resistentes. Avaliaram-se populações crescentes de M. enterolobii - 0, 500, 1.500, 3.000, 5.000 e 7.000 ovos e juvenis de segundo estádio (J2) por planta -, em um delineamento inteiramente casualizado. O patógeno apresentou padrão de parasitismo similar ao de M. incognita, tendo causado redução significativa de parâmetros morfológicos e agronômicos. O fator de reprodução do patógeno deve ser usado na seleção de genótipos de quiabeiro quanto à tolerância a M. enterolobii, em populações acima de 3.000 ovos ou J2.

Abstract: The objective of this work was to estimate the damage caused by Meloidogyne enterolobii in okra (Abelmoschus esculentus) and to verify the reliability of the reproduction factor as a suitable measure for selecting resistant okra genotypes. Increasing populations of M. enterolobii - 0, 500, 1,500, 3,000, 5,000, and 7,000 eggs and second-stage juveniles (J2) per plant, - were evaluated, in a completely randomized design. The pathogen showed a parasitism pattern similar to that of M. incognita, causing a significant decrease in morphological and agronomic traits. The pathogen reproduction factor should be used in the selection of okra genotypes for tolerance to M. enterolobii, in populations above 3,000 eggs or J2.

ABSTRACT Root-knot nematodes are among the main agents that negatively affect the pepper and sweet pepper crop (Capsicum annuum L.), especially Meloidogyne incognita, M. javanica, and M. enterolobii. The objective of this study was to evaluate genotypes of C. annuum L. var. annuum in their response to infection by M. incognita race 3, M. javanica, and M. enterolobii. The experiment was conducted using a completely randomized design arranged in a 27 × 3 factorial scheme with six replicates and each plot consisted of one plant. The experiment was carried out at the UNESP-FCAV in Jaboticabal, Sao Paulo, Brazil. The genotypes were in plastic pots containing an autoclaved mixture of soil, sand, and bovine manure under greenhouse conditions, and they were evaluated for the reproduction index and reproduction factor at 90 d after inoculation. Thirteen genotypes were classified as resistant, based on the reproductive factor, and highly resistant, based on the reproduction index, to M. javanica, while six were resistant and highly resistant materials to M. incognita race 3. No materials resistant to M. enterolobii were identified. The genotypes CNPH 698, CNPH 701, CNPH 702, CNPH 717, and CNPH 718 were simultaneously classified as resistant to M. incognita race 3 and M. javanica based on the reproduction factor.

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.

Abstract: 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.

<p>A temperatura elevada do local de cultivo pode afetar a qualidade pós-colheita dos frutos do tomateiro. Nessa situação, uma alternativa para os produtores, é o uso de cultivares híbridas que produzem frutos longa vida com maior tempo de conservação em pós-colheita, quando comparado com cultivares de frutos normais. Neste trabalho, objetivou-se avaliar a conservação em pós-colheita de frutos de híbridos de tomateiro longa vida estrutural e com mutante <italic>rin</italic> cultivados em duas épocas sobre ambiente protegido na região Sul do estado do Tocantins. Os tratamentos foram constituídos de 15 genótipos, sendo quatro híbridos com frutos tipo longa vida (com alelo <italic>rin</italic>) que foram: Tyler, Rebeca, Carmem e AF 13527; nove híbridos com frutos tipo longa vida estrutural: Lumi, Débora Max, Michelli, Tammy, AF 12525, AF 11097, AF 13363, AF 13364 e AF 13525 e duas cultivares de frutos normais: Santa Clara e Drica. Os frutos foram colhidos no estádio de <italic>breaker</italic>e armazenados em ambiente controlado (20 ºC e umidade relativa de 60%). A meia vida da firmeza dos frutos dos genótipos com <italic>background</italic> genotípico longa-vida estrutural variou de 6,25 a 13,44 dias nos genótipos Tammy e AF13525, respectivamente, não diferindo dos genótipos longa-vida com alelo <italic>rin</italic>. Apesar das temperaturas diurnas terem sido superiores às recomendadas para o cultivo do tomate, observou-se que, se os frutos forem colhidos no estádio de "breaker" a coloração e firmeza dos frutos nos genótipos longa-vida <italic>rin</italic> e <italic>background</italic> genotípico estrutural evolui mais lentamente que os frutos de genótipo normal, necessitando de 8 dias depois de colhidos para estarem com mais de 80% da superfície do fruto vermelha.</p>

<p>The high temperature of growth environment can affect the postharvest quality of tomato fruits. In this situation, an alternative for the farmers is the use of hybrid cultivars that produce long shelf life fruit with longer postharvest shelf life when compared to normal varieties of fruits. The objective of this research was to compare the postharvest conservation of fruits of structural long shelf life tomato hybrids and with the mutant<italic> rin</italic>. The fruits evaluated were from fifteen tomato genotypes produced under the edaphoclimatic conditions of the southern State of Tocantins, being four of them long shelf life type hybrids (with <italic>rin</italic> allele) which were: Tyler, Rebeca, Carmem and AF 13527; nine of them structural long shelf life hybrids: Lumi, Débora Max, Michelli, Tammy, AF 12525, AF 11097, AF 13363, AF 13364 and AF 13525; and two normal fruit cultivars: Santa Clara and Drica. The fruits were harvested at the breaker stage and stored in a controlled environment (20 °C and relative humidity of 60%). The half-life firmness of fruits of genotypes with a structural genotypic long shelf life background ranged from 6.25 to 13.44 days for the genotypes Tammy and AF13525, respectively, not differing from the long shelf life genotypes with <italic>rin</italic> allele. Despite the fact that daytime temperatures are higher than those recommended for the tomatoes crops, it was observed that if the fruits are stored in appropriate conditions (20 °C and relative humidity of 60%), the color and firmness of the fruits with a long shelf life genotypes with <italic>rin</italic> allele and structural genotypic background evolve more slowly than the fruits of normal genotypes. Under these conditions, it took the fruits 7 to 8 days to acquire a red color on more than 80% of the surface after being harvested.</p>