ABSTRACT
The aim of this study was to investigate the pathogens control in seeds of two soybean cultivars by the accelerated aging test. The experiment was conducted in the laboratories of the Department of Crops Production and Department of Entomology, Plant Pathology and Agricultural Zoology (USP-ESALQ), both from the Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo in Piracicaba, SP. For this we used seeds of two soybean cultivars (Embrapa 48 and FTS Águia). Seeds were harvested manually and mechanically, with 18%, 15% and 12% water and, immediately after harvest, evaluated for water content. After drying, the quality of the seeds was determined by germination test, seedling emergence, accelerated aging and health test. The incidence of pathogens in soybean seeds reduced in cultivar Embrapa 48 and FTS Águia, depending on the conditions of relative humidity and air temperature that were used in the accelerated aging test, especially for the seeds of cultivar FTS Águia.
O objetivo dessa pesquisa foi verificar o controle de patógenos em sementes de duas cultivares de soja, pelo teste de envelhecimento acelerado. O experimento foi realizado nos laboratórios de Sementes do Departamento de Produção Vegetal e no de Patologia de Sementes do Departamento de Entomologia, Fitopatologia e Zoologia Agrícola da USP-ESALQ, em Piracicaba, SP. Utilizaram-se sementes de duas cultivares de soja (Embrapa 48 e FTS Águia). As sementes foram colhidas, manual e mecanicamente, com 18%, 15% e 12% de água e avaliadas, após a colheita quanto ao teor de água. Após a secagem, a qualidade das sementes foi determinada pelos testes de germinação, emergência da plântula, envelhecimento acelerado e sanidade. Houve redução da incidência de patógenos nas sementes de soja, das cultivares Embrapa 48 e FTS Águia, em função das condições de umidade relativa e temperatura do ar que são utilizadas no teste de envelhecimento acelerado, especialmente para as sementes da cultivar FTS Águia.
ABSTRACT
Alternative use of the X-ray test to evaluate seed quality has become increasingly diverse. This study was performed primarily to establish experimental procedures and verify the effectiveness of the X-ray test to detect damage or abnormalities in bell pepper (Capsicum annuum) seed structure associated with germination. Five seed lots each of hybrids Reinger and Sentinel were used. Two hundred seeds per lot were exposed to durations and intensities of X-radiation and visually classified into four categories according to the proportion between the area occupied by the embryo and endosperm in relation to the total cavity area in the internal seed structure, e.g. 0, 50%, 50-75% and 100%. The last category was subdivided into two others based on the occurrence of morphological abnormalities. Seed samples obtained from different X-ray categories were then submitted to germination test at 25ºC for 14 days and subsequently compared with results of the X-ray analysis. Exposure to a 10 kV radiation for 260 s was the most suitable X-ray dose for visualizing seed structure. Seeds in which the area of the internal cavity occupied by the embryo and endosperm varied from 50-75% produced abnormal seedlings or did not germinate. Full seeds (100% of the internal cavity area occupied) with abnormal structure usually originated defective seedlings. As a consequence, the classification of bell pepper seeds according to the proportion occupied by the seed content (embryo + endosperm) allowed a reliable estimation of the degree of seed physical integrity based on X-ray analysis and its association with germination performance.
ABSTRACT
The aim of this study was to investigate the pathogens control in seeds of two soybean cultivars by the accelerated aging test. The experiment was conducted in the laboratories of the Department of Crops Production and Department of Entomology, Plant Pathology and Agricultural Zoology (USP-ESALQ), both from the Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo in Piracicaba, SP. For this we used seeds of two soybean cultivars (Embrapa 48 and FTS Águia). Seeds were harvested manually and mechanically, with 18%, 15% and 12% water and, immediately after harvest, evaluated for water content. After drying, the quality of the seeds was determined by germination test, seedling emergence, accelerated aging and health test. The incidence of pathogens in soybean seeds reduced in cultivar Embrapa 48 and FTS Águia, depending on the conditions of relative humidity and air temperature that were used in the accelerated aging test, especially for the seeds of cultivar FTS Águia.
O objetivo dessa pesquisa foi verificar o controle de patógenos em sementes de duas cultivares de soja, pelo teste de envelhecimento acelerado. O experimento foi realizado nos laboratórios de Sementes do Departamento de Produção Vegetal e no de Patologia de Sementes do Departamento de Entomologia, Fitopatologia e Zoologia Agrícola da USP-ESALQ, em Piracicaba, SP. Utilizaram-se sementes de duas cultivares de soja (Embrapa 48 e FTS Águia). As sementes foram colhidas, manual e mecanicamente, com 18%, 15% e 12% de água e avaliadas, após a colheita quanto ao teor de água. Após a secagem, a qualidade das sementes foi determinada pelos testes de germinação, emergência da plântula, envelhecimento acelerado e sanidade. Houve redução da incidência de patógenos nas sementes de soja, das cultivares Embrapa 48 e FTS Águia, em função das condições de umidade relativa e temperatura do ar que são utilizadas no teste de envelhecimento acelerado, especialmente para as sementes da cultivar FTS Águia.
ABSTRACT
Alternative use of the X-ray test to evaluate seed quality has become increasingly diverse. This study was performed primarily to establish experimental procedures and verify the effectiveness of the X-ray test to detect damage or abnormalities in bell pepper (Capsicum annuum) seed structure associated with germination. Five seed lots each of hybrids Reinger and Sentinel were used. Two hundred seeds per lot were exposed to durations and intensities of X-radiation and visually classified into four categories according to the proportion between the area occupied by the embryo and endosperm in relation to the total cavity area in the internal seed structure, e.g. 0, 50%, 50-75% and 100%. The last category was subdivided into two others based on the occurrence of morphological abnormalities. Seed samples obtained from different X-ray categories were then submitted to germination test at 25ºC for 14 days and subsequently compared with results of the X-ray analysis. Exposure to a 10 kV radiation for 260 s was the most suitable X-ray dose for visualizing seed structure. Seeds in which the area of the internal cavity occupied by the embryo and endosperm varied from 50-75% produced abnormal seedlings or did not germinate. Full seeds (100% of the internal cavity area occupied) with abnormal structure usually originated defective seedlings. As a consequence, the classification of bell pepper seeds according to the proportion occupied by the seed content (embryo + endosperm) allowed a reliable estimation of the degree of seed physical integrity based on X-ray analysis and its association with germination performance.