ABSTRACT. The production of maize doubled haploid (DH) lines is a technique commonly used by private companies, but not by Brazilian public institutions. Research on this technique is essential to develop and improve the production of DH lines grown under tropical conditions. We assessed the ability of a gynogenetic haploid inducer system to induce haploids in a tropical environment, assessed the induction rate of haploids identified using the R-navajo morphological marker, checked for interference from the generation of hybrid donors on haploid induction, measured the ability of flow cytometry, and simple sequence repeat marker techniques to identify doubled haploids. Seeds from the inducer Krasnodar Embryo Marker Synthetic (KEMS) line were sown in Ponta Grossa, PR, and Cravinhos, SP, and the plants were crossed to produce six hybrids and their F 2 generations. The seeds were separated according to the R-navajo morphological marker indicator of haploidy (purple endosperm and white embryo) and germinated in a controlled environment. Chromosomal duplication was performed in seedlings selected as putative haploids. We performed subsequent confirmation of ploidy and the success of duplication using flow cytometry and SSR 4231©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 12 (4): 4230-4242 (2013) Production of doubled haploid lines in tropical maize marker techniques. We concluded that DH lines can be obtained from hybrids crossed with the inducer KEMS line. The generation of inbred hybrids did not affect the induction rate or chromosomal duplication in haploids. The use of flow cytometry and SSR markers was effective in verifying chromosomal duplication in haploids.
ResumoDoze híbridos comerciais de milho foram intercruzados, conforme um dialelo completo. Esses genótipos e três testemunhas foram avaliados em látice triplo na região Centro-Sul do Paraná, nos municípios de Laranjeiras do Sul, Guarapuava e Cantagalo. Os dados referentes à produção de espigas despalhadas, altura de planta e altura de espiga foram submetidos à análise dialélica conjunta, segundo o método 4 de Griffing, em que foram avaliados apenas os F 1 . Foi verificado efeito significativo da capacidade geral de combinação (CGC), da capacidade específica de combinação (CEC) e da interação 'CGC x locais' para todos os caracteres. A interação 'CEC x locais' foi não significativa para as características avaliadas. Os híbridos P30F53 e AS1575 apresentaram estimativas positivas e elevadas da CGC para peso de espigas despalhadas e alta produtividade, mostrando-se promissores para geração de populações com bom potencial para obtenção de linhagens superiores no melhoramento intrapopulacional. Os híbridos P30F44 e 2B688 apresentam potencial para a geração de populações para melhoramento interpopulacional, pois apresentaram elevada média da produtividade de espigas despalhadas, estimativas positivas da CGC e da CEC, além de estimativas favoráveis para altura de espiga. Palavras-chave: Capacidade de combinação, dialelo, milho híbrido, Zea mays L AbstractTwelve commercial maize hybrids were intercrossed in a complete diallel. These genotypes and three checks were evaluated in lattice design with three replications in the South-Central region of Parana State, in Laranjeiras do Sul, Guarapuava and Cantagalo. Data of yield of husked ear, plant height and ear height were submitted to joint diallel analysis according to Griffings method 4, i.e. only F 1 were evaluated. Significant effect was found for general combining ability (GCA), specific combining ability (SCA) and interaction 'GCA x locations' for all characters. The interaction 'SCA x location' was not significant for both characters. Hybrids P30F53 and AS1575 showed positive and high estimates of GCA for yield of husked ear and high mean of yield, being interesting for the generation of populations with potential for intrapopulation breeding to obtain superior lines. The hybrids P30F44 and 2B688 are potentially indicated to generate populations for interpopulational breeding, since their high in yield of husked ears, positive GCA and SCA estimates, besides favorable estimates for ear height.
RESUMOA distribuição adequada das plantas de cebola (Allium cepa L.) na lavoura torna-se necessária devido a influência sobre a competição por água, luz e nutrientes, determinando o tamanho dos bulbos e a produtividade total. Objetivou-se, no trabalho, avaliar a produtividade e os padrões comerciais de bulbos de cebola, em função da densidade de plantio adotada. As mudas de cebola foram produzidas em bandejas de poliestireno de 200 células, com substrato comercial Plantimax®. O experimento foi instalado em delineamento experimental de blocos casualizados (DBC) com 4 repetições, com parcelas de 2 m 2 . Utilizou-se a cultivar Buccaneer, nas densidades de 50, 75 e 100 plantas m -2 . Foram avaliadas a produção comercial, a produção total e a massa média de bulbos. Observou-se que a densidade de 100 plantas m -2 proporcionou a maior produtividade (92,20 t ha -1 ). No entanto, a menor densidade de plantas avaliada proporcionou bulbos com a maior massa média (171g). As densidades de 50 e 75 plantas m -2 apresentaram os maiores valores distribuídos na classe 4 (> que 70 até 90 mm de diâmetro) e 3 cheio (> que 60 até 70 mm de diâmetro), respectivamente. A densidade de 100 plantas m -2 proporcionou uma maior quantidade de bulbos na classificação 3 cheio. Os resultados obtidos demonstraram que o aumento na densidade de plantas proporcionou uma maior produtividade, uma menor massa média de bulbos e uma maior produção na classificação comercial 3 cheio, considerada ideal para comercialização em função da preferência pelos consumidores. Termos para indexação:Allium cepa, densidade populacional, classificação comercial. ABSTRACTThe adequate distribution of onions (Allium cepa L.) within a crop becomes necessary due to their influence on the competition for water, light, and nutrients, which determines the size of the bulbs and the total yield. The goal of this work was to evaluate the yield and commercial pattern of onion bulbs as a function of the crop density employed. The onion seedlings were produced on polystyrene trays with 200 cells filled with commercial substrate Plantimax®. The experiment was carried out according to a randomized block design (RBD), with four replications and 2-m 2 plots. The cultivar Buccaneer was evaluated in densities of 50, 75, and 100 plants m -2 . The commercial bulb yield, the total yield, and the average mass of bulbs were evaluated. The density of 100 plants m -2 provided the greatest yield (92.20 t ha -1 ). However, the lower density of plants provided bulbs with the greatest average mass (171g). Densities of 50 and 75 plants m -2 presented the greatest values distributed in class 4 (> 70 up to 90 mm of diameter) and 3 full (> 60 up to 70 mm of diameter), respectively. Density of 100 plants m -2 provides a larger amount of bulbs in the 3-full classification. The results obtained in this experiment showed that an increase in the density of plants provided greater yield, smaller average mass of bulbs and greater production in the commercial 3-full classification, which is considered ideal for...
ABSTRACT. Twelve corn hybrids recommended for cropping in the south-central region of the Paraná State and 66 crossings obtained among these hybrids were evaluated for agronomic and morphological traits. These genotypes were evaluated in three experiments performed in Laranjeiras do Sul, Guarapuava and Cantagalo, Paraná State, Brazil. Heterosis and specific combining ability (SCA) were estimated for yield of husked ears. Data from measuring 22 morphological/agronomical traits of the parents were subjected to a multivariate joint analysis of variance and cluster analysis to group the parental hybrids via the neighbor method, using the generalized Mahalanobis distance. Pearson correlation coefficients between heterosis, SCA, D 2 and yield of husked ears were obtained. The cross P30F44 x Sprint displayed a high mean and a high heterosis for yield of husked ears, but a moderate estimate of genetic divergence. Estimates of genetic divergence were not effective at predicting the most heterotic crossings, as Pearson correlation coefficients between D 2 and heterosis and D 2 and CEC were not significant. Positive significant correlations were observed between yield means and CEC and heterosis.Keywords: Zea mays, specific combining ability, Mahalanobis distance, plant breeding.Divergência genética entre híbridos de milho e correlações com heterose e capacidade de combinação RESUMO. Doze híbridos de milho recomendadas para a região centro-sul do Paraná e os 66 cruzamentos obtidos entre eles foram avaliados quanto a caracteres agronômicos e morfológicos em Laranjeiras do Sul, Guarapuava e Cantagalo, Estado do Paraná. Foi calculada a heterose e estimada a capacidade específica de combinação (CEC) dos cruzamentos para o caráter produção de espigas despalhadas. Foram tomadas medidas de 22 caracteres morfoagronômicos dos 12 genitores e os dados foram submetidos à análise multivariada conjunta com agrupamento pelo método hierárquico do vizinho mais próximo, utilizando a distância generalizada de Mahalanobis (D 2 ). Foram obtidas correlações entre a heterose, CEC, D 2 e média da produtividade. O cruzamento P30F44 x Sprint revelou média alta e elevada heterose para peso de espigas despalhadas, embora tenha apresentado estimativa moderada da divergência genética. As estimativas de divergência genética não foram eficientes na predição dos cruzamentos mais heteróticos, pois as correlações entre D 2 e heterose e entre D 2 e CEC foram não significativas. Houve correlações positivas e significativas entre as médias de produção de espigas, a CEC e a heterose.Palavras-chave: Zea mays, capacidade específica de combinação, distância de Mahalanobis, melhoramento vegetal.
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