Search

ABSTRACT The quality of seeds is influenced by the climatic conditions of the production field. The identification of characteristics of the best forage seed fields allows the improvement of the sector. In this study, the aim was to identify climatic characteristics of producing regions that may affect the physical and physiological quality of Brachiaria brizantha cv. BRS 'Piatã' seeds. Seeds from 10 lots were evaluated for purity, other seeds, mass of a thousand seed, water content, germination, dormancy, emergence, seedling emergence in sand and seedling emergence in the field. Temperature and precipitation data of each production field from flowering to harvest were obtained. The means of treatments were compared by the Scott-Knott test at 5% probability. In order to discriminate which environmental factors influenced seed quality, multivariate statistical analysis was applied through Principal Component Analysis. It was concluded that production fields with temperatures above 30 °C in flowering, threshing and harvesting periods are related to the production of 'Piatã' grass seeds of lower physical and physiological quality. Fields with accumulated rainfall above 500 and 137 mm in the flowering and harvesting period, respectively, are unfavorable to seed vigor.

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.

ABSTRACT Identifying fast and efficient tests to evaluate the vigor of forage grass seed lots is desirable in the quality control programs of the companies in this sector. Thus, the objective was to evaluate the efficiency of vigor tests on the physiological quality of seeds of Panicum maximum, cv. Mombasa, for the differentiation of lots and prediction of seedling emergence in the field. Nineteen seed lots were subjected to evaluations of moisture content, germination, first count, germination speed index, seedling emergence in sand, first count of seedling emergence in sand, seedling root and shoot lengths, seedling emergence in the field and computerized analysis of seedling images obtained through SVIS® software. The experimental design was completely randomized for the tests performed in the laboratory and randomized blocks for the emergence test in the field. The data were subjected to analysis of variance and the means were compared by Scott-Knott test at 5% probability level. Cluster analysis of seed lots and principal component analysis were performed. The uniformity index, evaluated by image analysis and by the root length test, is efficient in evaluating the physiological potential of seeds of Panicum maximum, cv. Mombasa, providing information similar to those obtained with the test of seedling emergence in the field.

Pithecellobium dulce destaca-se por apresentar potencial madeireiro e forrageiro, além de diminuir o risco de erosão do solo, aumentar a fixação de nitrogênio e possuir propriedades medicinais. A profundidade e a posição de semeadura são fatores importantes dentro do processo de germinação por garantir um desenvolvimento rápido e uniforme das plântulas. O objetivo deste estudo foi avaliar a influência da posição e da profundidade de semeadura na emergência e no desenvolvimento inicial de plântulas de P. dulce. Utilizou-se o delineamento inteiramente ao acaso, com quatro repetições de 25 sementes, dispostos em esquema fatorial 3 × 4 (posições e profundidades de semeadura). As posições de semeadura consistiram em: hilo voltado para cima (HC), hilo de lado (HL) formando um ângulo de 90º em relação ao eixo imaginário com o substrato e hilo voltado para baixo (HB). As profundidades de semeadura foram de 1,0, 2,0, 3,0 e 4,0 cm. Após 30 dias da semeadura, avaliaram-se a percentagem de emergência de plântulas, o índice de velocidade de emergência, o comprimento da parte aérea, o comprimento da raiz, o número de folhas e a massa da matéria seca total. A semeadura de sementes de P. dulce deve ser realizada na profundidade de até 3,0 cm com o HL.

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.

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.

Os testes de germinação e de vigor são componentes essenciais do processo de controle de qualidade das empresas produtoras de sementes, e o teste de envelhecimento acelerado é um dos mais utilizados para avaliação do vigor de sementes. Nesse sentido, a pesquisa teve como objetivo estudar a metodologia do teste de envelhecimento acelerado, visando à identificação de diferentes níveis de vigor de lotes de sementes de quiabo (Abelmoschus esculentus (L.) Moench). Para isso, quatro lotes de sementes da cultivar 'Colhe Bem' e cinco lotes da cultivar 'Santa Cruz 47' foram submetidos às seguintes avaliações: germinação, emergência de plântulas, envelhecimento acelerado tradicional e em solução saturada com NaCl (38 e 41ºC durante 24, 48, 72 e 96 horas) e grau de umidade no início dos testes e após a incubação para o teste de envelhecimento acelerado. Os testes de envelhecimento acelerado tradicional e em solução saturada com cloreto de sódio, a 41ºC durante 96 horas, constituem em opções promissoras para detectar diferenças de vigor entre lotes de sementes de quiabo.

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.

ABSTRACT This study aimed to verify the efficiency of multivariate analysis in the identification of promising vigor tests for the evaluation of the physiological quality of seed lots of Brachiaria decumbens cv. Basilisk. Seeds of B. decumbens cv. Basilisk were tested for the following parameters: water content, germination, first germination count, cold test, electrical conductivity, seedling growth, seedling dry mass, first count and emergence percentage of seedlings in laboratory substrate, and seedling emergence in the field. The data obtained in each test-all completely randomized experimental designs-were analyzed separately by means of analysis of variance, Scott-Knott’s test, and multivariate analysis. Principal component analysis is efficient to discriminate vigor and seed germination tests capable of identifying the top performance batch in the field. Germination, first germination count, emergence of seedlings in sand, first seedling emergence count in sand, shoot length, and the cold test are promising in the evaluation of the physiological quality of seed lots of B. decumbens cv. Basilisk, providing similar information to that from the emergence of field seedlings.