Sheila Fanan

Condicionamento fisiológico de sementes de berinjela

The objective of this research was to study priming methods of eggplant seeds. Three seed lots of the Napoli cultivar were conditioned between paper towels )with 30, 60 and 90 mL of water at 15, 20 and 25 °C), and with PEG solutions (-0.5, -1.0, -1.5, and -2.5 MPa at 20 °C); following that, seeds were dried at 30 °C until water contents similar to original ones. The unconditioned (check) and conditioned seeds were evaluated in relation to water content, germination and vigor (speed of germination, accelerated aging, controlled deterioration and electrical conductivity). The most effective treatments (20 °C, with water or -0.5 MPa PEG) were again applied to other samples of same seeds which, together with the those of the check, were stored and evaluated through the same tests at 0, 60 and 120 days. Results showed that there is the possibility of conditioning eggplant seeds at 20 °C, between paper towels, with water or with solution of -0.5 MPa PEG 6000, followed by drying.

Descrição de características agronômicas e avaliação de épocas de colheita na produtividade da mamoneira cultivar IAC 2028

DESCRIPTION OF AGRONOMIC CHARACTERISTICS AND HARVEST TIME EVALUATION IN THE YIELD OF CASTOR BEAN CULTIVAR IAC 2028 The crop of castor bean can be used like raw material for renewable energy, however, becomes necessary the use of agricultural machines adapted to its harvest. During the crop growth racemes are produced under different environmental conditions which can cause variations in productivity of the crop. The purpose of this work was to evaluate important agronomic characteristics to mechanical harvest as well as the effect of time of harvest in productivity of castor bean. The experimental design was arranged in a randomized block design with eleven treatments and five replications, with cultivar IAC 2028 , during the agricultural year of 2005/06 at the Centro Experimental Central, Instituto Agronomico (IAC), Campinas, Sao Paulo State, Brazil. Seed yield, number of fruits and seeds per raceme and mass of a thousand seeds were evaluated. In the evaluation of the agronomic characteristics was observed a great variability among the plants, what can complicate mechanical harvest. The results showed that the secondary raceme was the most influence to total productivity and the harvest of the racemes, fruits and seeds, in the conditions of this experiment, can be performed at only time with no decrease in yield.

Ramularia areola sporulation potential in Brazilian cotton

A mancha de ramularia causada por Ramularia areola e uma das mais importantes doencas para a cultura do algodoeiro no Brasil. Para o controle efetivo da doenca, sao necessarias 5-9 aplicacoes de fungicidas em cultivares suscetiveis. O objetivo do presente trabalho foi avaliar, in vitro e in vivo, o potencial de esporulacao de isolados de R. areola, originarios de diferentes regioes do Brasil, sob diferentes regimes de temperaturas. A producao de esporos foi avaliada em laboratorio e em folhas de plantas de oito cultivares de algodoeiro em condicoes de casa-de-vegetacao. Os resultados obtidos in vitro indicaram que o potencial de producao de esporos foi dependente da temperatura. A maxima esporulacao do fungo ocorreu com 17oC para isolados originarios do Estado de Sao Paulo e 23oC para isolados de Goias e Mato Grosso. No estudo in vivo, houve variacao na esporulacao em funcao da cultivar e do isolado. A maioria dos isolados apresentou alta agressividade na cultivar FM 966 LL e DELTAOPAL. Com os resultados obtidos, e possivel indicar uso mais racional de fungicidas, cultivares que apresentaram menor esporulacao do fungo, alem de formar base para novos estudos com relacao a variabilidade desse fungo em algodoeiro no Brasil. Esse e o primeiro relato sobre o potencial de esporulacao de isolados brasileiros de R. areola.

Desempenho de genótipos de algodoeiro na presença ou não de rotação de cultura com Crotalaria spectabilis, em área infestada com Meloidogyne incognita

In an area naturally infested with Meloidogyne incognita race 3, located in Primavera do Leste, Mato Grosso State, Brazil, the performance of 21 cotton genotypes having different levels of tolerance to this parasitic nematode was studied, in the presence or absence of crop rotation with Crotalaria spectabilis. A general trend was observed for crop rotation to reduce the severity of symptoms exibited by plant sowing to nematode incidence, and lead to increased cotton yield. However, its effect was not sufficient to increase the performance of genotypes with low tolerance to the parasite, which, even under the crop rotation schem, had disease sympton rates that were 142% higher and cotton yields that were 57% lower than those obtained for more tolerant genotypes. High correlation between average yield in the presence or absence of crop rotation, and absence of interaction between genotype and crop rotation, indicated that, although at higher yield level being achieved, the tendency of genotype performance remained the same in both systems. The yield of the three more tolerant genotypes in the absence of crop rotation was 48% superior to that of the three least tolerant genotypes under crop rotation. The minimum possible losses, attributable to the use of susceptible genotypes, were estimated at 37% and 29%, respectively, without crop rotation being used or under conditions of crop rotation.

Influência da colheita e períodos de armazenamento na qualidade sanitária de sementes de mamoneira

As atuais preocupacoes quanto a escassez das reservas de petroleo e o agravamento do efeito estufa, pela emissao de CO2, levam a cultura da mamona a ser uma das fontes para energia renovavel. Sabe-se que ao longo do ciclo da mamona sao produzidos racemos de varias ordens, que se desenvolvem sob diferentes condicoes ambientais, podendo provocar variacoes na qualidade das sementes. Assim, objetivou-se avaliar a interferencia da colheita e de cinco periodos de armazenamento na qualidade sanitaria das sementes de mamona, cultivar IAC-2028. Para tanto, foram instalados os testes de germinacao e sanidade, logo apos a colheita e aos 3; 6; 9 e 12 meses de armazenamento em condicoes nao controladas de temperatura e umidade relativa do ar. As avaliacoes foram feitas em esquema de parcela subdividida no tempo, onde as parcelas foram constituidas por cinco epocas trimestrais de avaliacao e as sub-parcelas por 11 tratamentos. Os resultados sugerem que todos os racemos podem ser colhidos em uma unica etapa, sem que ocorram perdas de qualidade das sementes.