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Investigation into "bud blast" in the Easter lily (Lilium longiflorum Thunb)Mason, Michael Regis, 1962- January 1989 (has links)
Ethylene and carbohydrate deprivation were investigated as possible causes of bud abortion in Lilium longiflorum Thunb. Silver thiosulfate (STS) was investigated as an inhibitor of ethylene-induced abortion. Fourteen days of 92.5% irradiance reduction increased bud abortion when plants were exposed to 2.07 mM ethephon. Percent bud abortion was 39% and 60% for plants grown in full irradiance and reduced irradiance, respectively. Ethephon resulted in 54% abortion, regardless of irradiance at 4.15 mM. A 70% irradiance reduction for 14 days did not increase bud abortion when plants were treated with ethephon. STS was applied to plants at visible bud +2 weeks followed by ethephon application 2 days later. Bud abortion was reduced from 69 to 13% with 2 mM STS; the STS x ethephon interaction was significant. STS inhibited ethephon-induced bud abortion when applied at visible bud, 4 weeks prior to ethephon application; However, STS application at flower bud initiation did not prevent/reduce ethephon-induced bud abortion.
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Florescimento da cana-de-açúcar : efeitos genotípicos, climáticos, perdas e estratégias de controle /Cardozo, Nilceu Piffer, 1980. January 2017 (has links)
Orientador: Carlos Alexandre Costa Crusciol / Banca: Alan Rodrigo Panosso / Banca: Paulo Alexandre Monteiro de Figueiredo / Banca: Fernando Cesar Pattaro / Banca: Hideto Arizono / Resumo: O cultivo da cana-de-açúcar sofreu muitas mudanças nos últimos 15 anos. Extinção da queima, mecanização completa do plantio e colheita, expansão rumo a áreas de cerrado são apenas algumas delas. Entretanto, alguns velhos e bem conhecidos problemas permanecem presentes. Embora conhecido e extensamente estudado, o florescimento da cana-de-açúcar continua a causar perdas de produtividade. O método de controle mais utilizado envolve o uso de ethephon, o qual, apesar de conhecida eficiência, não raro tem seus resultados questionados, principalmente por uso inadequado. O objetivo do presente trabalho foi caracterizar as variáveis envolvidas no processo de florescimento que afetam a eficiência de seu controle pelo ethephon e propor estratégias de manejo que otimizem seus resultados. O trabalho foi realizado durante os anos de 2014 e 2016 em quatro regiões produtoras de cana-de-açúcar do centro-sul brasileiro e envolveu a avaliação do uso de ethephon em diferentes épocas de aplicação em três cultivares de cana-de-açúcar. Os melhores resultados foram obtidos com aplicações realizadas entre 20 dias antes à 5 dias após o início do período indutivo (P.I.). O ponto ótimo de controle ocorreu quando a aplicação foi realizada entre 9 a 6 dias antes do início de P.I. A menor intensidade de florescimento foi acompanhada dos maiores ganhos em produtividade (p<0,05), com média oscilando entre 12 a 16 % em relação à testemunha. Aplicações realizadas durante e após o término do P.I. apresentaram r... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sugarcane growth in Brazil has undergone many changes in the last 15 years. Extinction of trash burning, complete mechanization of planting and harvesting, expansion to Cerrado areas are just a few of them. However, some old and well-known problems remain. Despite being widely studied; the sugarcane flowering continues to promote yield losses. The most used method of control is ethephon, despite known efficiency, often has its results questioned, mainly due to inadequate use. The aim of this work was to characterize the variables involved in the flowering process that affect the efficiency of its control by ethephon and to propose management strategies that optimize its results. The work was carried out during the years 2014 and 2016 in four sugarcane producing regions of Brazil and involved the evaluation of ethephon sprayed in different dates and cultivars. The best results were obtained in sprays carried out between 20 days before and 5 days after the beginning of the inductive period (I.P.). The optimal spraying date was about 9 to 6 days before I.P. The lower flowering intensity was accompanied by higher yield (p<0.05), ranging from 12 a 16% compared to the control. Spraying done during and after the I.P. showed a gradual reduction in the efficiency flowering control. However, there was delay in panicle emission and reduction in the intensity of adverse factors such as pith, with a mean reduction of 40% compared to the control. Although its lower yields, those spraying dates showed higher yield (p<0.05) than the control, with an average of 6%. The anticipation of the control (over 25 to 30 days) was also inefficient in the flowering control and with has lower yields than spraying done later, even, those ones done after the end of I.P. Pith intensity was related to flowering, but also to the time of panicle exposure in the field and, mainly, to the conditions of water restriction. The use of ... / Doutor
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