RESUMO -O parâmetro mais utilizado para avaliar a qualidade fisiológica de sementes é o teste de germinação. No entanto, sementes de citros apresentam germinação lenta e o teste de germinação pode ser prolongado por até 60 dias. Dessa maneira, surge a necessidade do desenvolvimento de testes rápidos para estimar a viabilidade das sementes. A avaliação da qualidade fisiológica de sementes de citros, por meio de testes rápidos, pode ser considerada como um recurso extremamente útil, para as empresas produtoras de sementes, possibilitando um controle de qualidade mais rápido e eficiente. Desse modo, o objetivo da pesquisa foi adaptar metodologias de testes rápidos, para avaliar a viabilidade de sementes Citromelo swingle em quatro épocas de armazenamento. Foram utilizados os testes de tetrazólio, condutividade elétrica e o do pH do exsudato (fenolfetaleína), enquanto, os testes de emergência das plântulas e de germinação foram usados para a comparação dos resultados. Os testes rápidos para avaliar a viabilidade mostraram-se promissores para o monitoramento da germinação e emergência das plântulas, a partir do terceiro mês de armazenamento e na ausência de sementes dormentes.Termos para indexação: qualidade fisiológica, sementes, citros. RAPID TESTS FOR EVALUATING THE PHYSIOLOGICAL QUALITY OF Citromelo swingle SEEDSABSTRACT -The most utilized parameter to evaluate the physiological quality of seeds is the germination test. However, citrus seeds present slow germination and germination test may be extended for up to 60 days. In this way, the need for the development of rapid tests to estimate the viability of seeds appears. The evaluation of the physiological quality of citrus seeds by means of fast tests may be considered as an extremely helpful resource for seed-producing enterprises in the sense of enabling a faster and more efficient quality control. So, the objective of this research work was to adapt rapid test methodologies to determine the viability of Citromleo swingle seeds assessed in four storage periods. The tests of tetrazolium, of electric conductivity and of exudate pH (phenolphetaleine) were employed. The test of emergence on tray and germination pattern were utilized for comparing the results obtained in those above-quoted. The rapid tests for evaluating viability proved promising for germination monitoring and seedling emergence from the third month's storage and in the absence of dormant seeds emergence from the third month's storage.Index terms: physiological quality, seeds, citrus. INTRODUÇÃOO teste mais utilizado para avaliar a qualidade fisiológi-ca de sementes de diferentes espécies é o de germinação, por ser reproduzível. No entanto, esse teste é realizado em condições favoráveis e ótimas para a espécie, não refletindo o comportamento das sementes no campo. Além desse aspecto, esse teste não detecta estágios de deterioração das sementes (França-Neto et al., 1986).
ABSTRACT. Doubled haploid technology has been used by various private companies. However, information regarding chromosome duplication methodologies, particularly those concerning techniques used to identify duplication in cells, is limited. Thus, we analyzed and characterized artificially doubled haploids using microsatellites molecular markers, pollen viability, and flow cytometry techniques. Evaluated material was obtained using two different chromosome duplication protocols in maize seeds considered haploids, resulting from the cross between the haploid inducer line KEMS and 4 hybrids (GNS 3225, GNS 3032, GNS 3264, and DKB 393). Fourteen days after duplication, plant samples were collected and assessed by flow cytometry. Further, the plants were transplanted to a field, and samples were collected for DNA analyses using microsatellite markers. The tassels were collected during anthesis for pollen viability analyses. Haploid, diploid, and mixoploid individuals were detected using 7000 E.G. de Oliveira Couto et al.©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (2): 6999-7007 (2015) flow cytometry, demonstrating that this technique was efficient for identifying doubled haploids. The microsatellites markers were also efficient for confirming the ploidies preselected by flow cytometry and for identifying homozygous individuals. Pollen viability showed a significant difference between the evaluated ploidies when the Alexander and propionic-carmin stains were used. The viability rates between the plodies analyzed show potential for fertilization.
The objectives in the present work were to identify maize double haploids one generation after chromosome duplication through the evaluation of phenotypic characteristics in thr field, flow cytometry and molecular markers SSR. The seeds used in the present study were obtained from a cross between four simple hybrids (DKB393, GNS 3225, GNS 3264, GNS 3032) and the KEMS inducer of gymnogenetic haploidy, used as a male parent. Seeds from this crossing were selected according to the R-Navajo marker and those considered haploid, were submitted to two different chromosome duplication protocols. Plants that survived to the chromosome duplication protocols were acclimatized in greenhouse and later transplanted to the field. After self-fertilization of the DH0 plants, the DH1 seeds obtained were seeded in the field, divided into treatments according to the parental and duplication protocols. At the vegetative stage V4 of the DH1 seedlings, leaf tissue samples were collected to identify ploidy via flow cytometry and DNA analyzes using microsatellite markers. These results were confronted with the morphological characteristics of the future DH1 plants developed in the field, evaluated with the use of descriptive tools. Statistical analyzes were performed using the generalized linear modeling approach and the exploratory and inferential analyzes of datas, by the use of graphical resources, barplot and boxplot. For the analysis of variance, were used the Student-Newman-Keuls test, and the Pearson's correlations. It was not observed uniformity of phenotypic characteristics of plants subjected to duplication protocols in the field and the use of descriptive tools in the morphological analysis of adult maize plants must be done carefully to avoid the wrong classification of determined genotypes related to the ployd. Flow cytometry must be used as screening in the identification of possible DH´s and the molecular markers SSR can be used to prove the genetically inherited KEMS lineage and also to identify the double-haploid corn plants.
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