Sobrevivência de fungos associados ao potencial fisiológico de sementes de triticale (X. triticosecale Wittmack) durante o armazenamento

Abstract

rESuMo -Sementes de triticale de um lote do cultivar IAC-2, com 85% de germinação e incidência natural de Pyricularia grisae (34.5%), Bipolaris sorokiniana (12%), Fusarium graminearum (15%) e Alternaria alternata (35%), foram armazenadas em câmara fria, a 10 ºC, e em local sem controle das condições do ambiente, por doze meses. O potencial fisiológico foi avaliado em intervalos bimestrais, utilizando-se os testes de germinação, de envelhecimento acelerado, de tetrazólio e de emergência de plântulas no campo; a sobrevivência dos fungos foi avaliada por meio do teste de papel de filtro. As sementes mantiveram o nível de viabilidade e de vigor e a incidência de fungos patogênicos foi pouco alterada no armazenamento a 10 ºC. Em condições de ambiente não controlado, a germinação e a viabilidade das sementes armazenadas decresceram, aumentando a quantidade de sementes mortas devido à maior velocidade de deterioração e a um nível crescente de fungos de armazenamento, principalmente de Penicillium spp. nestas condições, a incidência dos fungos patogênicos decresceu continuamente até o final do período de armazenamento, atingindo valores muito baixos; porém na época recomendada para a semeadura da cultura no Estado de São Paulo (mês de abril), a sobrevivência destes patógenos ainda comprometia a qualidade sanitária das sementes.termos para indexação: X. triticosecale Wittmack, sementes, armazenamento, vigor, germinação. SurvIvAl oF SEEd-bornE FungI ASSoCIAtEd to thE PhySIologICAl quAlIty oF trItICAlE (X. triticosecale Wittmack) StorEd SEEdSAbstrAct -triticale seeds of the IAC-2 cultivar presented germination of 85% after harvest and natural incidence of the following pathogenic fungi: 34.5% Pyricularia grisae, 12% Bipolaris sorokiniana, 15% Fusarium graminearum and 35% Alternaria alternata. the seeds were stored at 10 ºC and under natural ambient conditions for twelve months. the seed physiological quality was evaluated at bimonthly intervals by the germination, accelerated aging, tetrazolium and field emergence tests and fungi survival was evaluated by the blotter test. the seeds stored at 10 ºC maintained the same level of germination, viability and vigor for twelve months even though the fungi incidences also remained almost unchanged too. the germination and viability of seeds stored under natural ambient conditions decreased and the level of dead seeds increased due to a higher speed of deterioration and an increased level of storage fungi, mainly Penicillium spp.. the pathogenic fungi levels decreased, reaching very low values at the end of the storage period. however, the pathogen survival was still harmful at the time of the planting season (April).

Sanitary analysis, transmission and pathogenicity of fungi associated with forage plant seeds in tropical regions of Brazil

“…Medina et al (2009) observed lack of effects resultant from the incidence of Curvularia lunata (0.5 to 1.5%) and Phoma spp. (0.5 to 4.0%) in the X. triticosecale Wittmack seed germination and in the transmission of these pathogenic elements to the seedlings.…”

Biometric description of fruits and seeds, germination and imbibition pattern of desert rose [Adenium obesum (Forssk.), Roem. & Schult.]

“…There are also scientific studies related to the cytotoxic compounds produced by this plant in the fight against cancer cells (Nakamura et al, 2000) and the influenza virus (Kiyohara et al, 2012). The propagation of the species occurs mainly by seeds, whereas plants from seeds present more developed caudex and main root when compared to the ones propagated by cuttings.…”

“…As in the germination process, humidity and temperature can trigger physiological processes during the storage phase and thereby accelerate the seeds deterioration or promote the growth of pathogens (Pontes et al, 2006;Medina et al, 2009).…”

Survey, survival and control of Alternaria alternata in wheat seeds

“…A. alternata has also been detected in seeds from other crops, including rye (Bollen et al, 1983), soybean (Baird et al, 1997), cotton (Pizzinatto et al, 2005), beans (Moraes and Menten, 2006), coriander (Reis et al, 2006) and barley (Roháčik and Hudec, 2007).…”

“…Species of saprophytic or pathogenic Alternaria sp. can be found on wheat leaf spots (Zillinsky, 1984) and the presence of A. triticina Prasada and Prabhu, causing wheat leaf spot in Argentina (Perelló and Sisterna, 2006), raises the hypothesis that the pathogen may be present in seeds and grains imported from Argentina but have remained undetected as yet, since it is classified as an Absent Quarentenary Pest (A1) (Brasil, 2008).…”