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ABSTRACT The X-ray test permits the visualization of the internal structures of seeds in a non-destructive way making thus possible the diagnosis of causes of seed low germination and purity. The objective of this project was to evaluate the quality of Brachiaria brizantha seeds by means of the X-ray test and the effect of the processing stage. The seeds were sampled before processing and after going through the air and screen machine, and the first and the second gravity tables. Seeds were evaluated as to water content, purity, weight of a thousand seeds, germination, and the X-ray test. The treatment replications were distributed according to a complete random design with four replications. The X-ray test permit to verify the completely full seeds as well as deteriorated, hollow, mechanically damaged seeds and empty spikelets. The processing procedure caused no damage to the seeds. The analysis by means of X-ray is a quality control procedure resulting in information that can be used in the adjustments of processing machines.

This research aimed to evaluate different methods for breaking dormancy in seeds of Pithecellobium dulce (Roxb.) Benth., arboreal species of multiple use in the semiarid region of Northeast Brazil. The treatments were: control – intact seeds (T1); immersion in water until it reaches 80 °C (T2), and 100 °C (T3), concentrated sulfuric acid for five minutes (T4), 10 minutes (T5 ), and 15 minutes (T6), mechanical scarification with sandpaper number 80 (T7), mechanical scarification with sandpaper number 80 + immersion in water for six hours (T8), and for 12 hours (T9), soaking in water for 24 hours (T10), and for 48 hours (T11). The characteristics evaluated were such: emergency, mean emergency time, shoot length, root length, number of leaves, leaf area and total dry matter. The best method for breaking dormancy of seeds of Pithecellobium dulce (Roxb.) Benth. is mechanical scarification with sandpaper number 80.

The incidence of fungi in seeds depends on the sanitary and climatic conditions in which the seeds were produced. So, the objective of this study was to identify the fungi present in commercial lots of Brachiaria brizantha cv. 'Marandu' and'Xaraés' seeds harvested in different areas in Brazil. Seeds from ten lots of each cultivar, produced in the Brazilian states of Mato Grosso do Sul, Mato Grosso, Goiás, Minas Gerais, São Paulo, and Bahia were evaluated as to moisture content, germination and sanity. The experiment was conducted according to a completely random design with eight replications of 50 seeds for each lot. In both cultivars, the seeds were found to be infected with Aspergillus sp., Chaetomium sp., Curvularia sp., Fusarium sp., and Helminthosporium sp; the highest incidences were those of Chaetomium  sp. and Fusarium sp. Seeds of the 'Marandu' cultivar were the only ones showing the presence of Phoma sp. and Pyricularia grisea and those of the 'Xaraés' cultivar with Colletotrichum sp. and Nigrospora sp. The incidence of Fusarium sp., Aspergillus and Nigrospora sp. reduces 'Xaraés' seeds germination whereas it does not interfere in the 'Marandu' seeds germination. The presence of the fungus Pyricularia grisea is for the first time reported in tropical forage grass seeds produced in the Southeast and Northeast regions of Brazil.

Um aspecto importante da produção de sementes é a determinação da maturidade fisiológica e do momento adequado de colheita, visando obter sementes de alta qualidade, minimizando a sua deterioração no campo. Diante disso, esta pesquisa teve por objetivo estudar a influência do estado de maturação dos frutos e dos períodos de repouso pós-colheita na qualidade fisiológica de sementes de pimenta (Capsicum baccatum L.), variedade Dedo-de-Moça, para determinação do ponto adequado para colheita das sementes. Os frutos foram colhidos em quatro estádios de maturação, com base na sua coloração: verde intenso (15 DAA), verde amarelado (25 DAA), verde avermelhado (35 DAA) e vermelho intenso (45 DAA) e submetidos ao armazenamento por 0; 5 e 10 dias para então, proceder à extração das sementes. Foram determinados o peso dos frutos, comprimento, diâmetro e espessura da polpa. A qualidade das sementes foi avaliada pelos testes de germinação, primeira contagem de germinação, emergência de plântulas, grau de umidade, massa seca de 100 sementes, peso de mil sementes e condutividade elétrica. Diante dos resultados, conclui-se que a maturidade fisiológica das sementes de pimenta, variedade Dedo-de-Moça, é indicada pela coloração vermelho intenso dos frutos (45 DAA); o repouso pós-colheita dos frutos por dez dias melhora o potencial fisiológico das sementes.

ABSTRACT Massai grass is an important tropical forage grass. The harvested seeds upon being received by the company, are found to be contaminated with impurities which are removable by processing machines. This procedure is necessary to produce seeds of a quality level within standards established for commercialization and sowing purposes. The objective of this project was to evaluate the effects of processing phases on the physical and physiological quality of massai grass (Panicum maximum x P. infestum, cv. Massai) seeds for commercialization purposes. Seeds were sampled before processing and after leaving the air and screen machine (upper and intermediary screens and bottom); first gravity table (drift, upper and intermediate spouts); treating machine; and second gravity table (upper, intermediate, and lower spouts). Seeds were evaluated as to water content, physical (purity and 1,000 seeds weight) and physiological quality (germination, first count of germination, seedling vigor classification, accelerated aging, seedling emergence in the field, speed of emergence index, and primary root length, shoot length). Massai grass seeds had their physical and physiological qualities improved when they were processed by an air and screen machine and a gravity table. Seeds from the intermediate discharge spout of the first gravity table, after going through the air and screen machine, are those of with highest physiological potential. The seeds of this species do not need to be processed to fit the germination and purity standards when the national market is the goal.