Selection for cacao resistance to Moniliasis assisted by molecular markers

The basidiomycete Moniliophthora roreri, the causal agent of moniliasis, occurs in many cocoa producer countries in South and Central Americas, but not yet in Brazil. The disease can cause losses of up to 90% in cocoa production, have difficult control and, given its proximity to the border with Brazil, it threatens Brazilian cocoa production. As part of a preventive breeding program, this study aims to identify parental germplasms to be involved in crosses aiming the development of varieties resistant to moniliasis and then select individual trees carrying the QTLs of resistance, assisted by markers. In order to do that, genomic DNA was extracted from 34 clones of CEPEC´s cacao breeding program with good agronomic characteristics and others with known resistance moniliasis and with QTLs mapped. Genomic DNA was extracted according to Doyle & Doyle (1991). Subsequently the DNA was amplified by PCR using primers close to the resistance genes, submitted to the SSR gel and silver stained. It was observed that some parental clones (Sca-6, Salobrinho-3, CP-184, CP-188), even being susceptible, carry the alleles of resistance in the marker loci and so should be avoided as parent in the marker assisted selection program. (Texte intégral

Produção de fitomassa, teor e produtividade do óleo essencial de Baccharis dracunculifolia DC. em função da adubação orgânica

Objetivou-se avaliar a produção de fitomassa, teor e produtividade do óleo essencial de Baccharis dracuculifolia DC., em função de doses de adubo orgânico, e foram utilizadas mudas produzidas por semente, e mantidas sob sombrite pelo período de 84 dias até serem transplantadas para o campo, no espaçamento de 1,0 x 1,0 m, com irrigação por gotejamento. O delineamento estatístico utilizado foi em blocos ao acaso, com quatro repetições, e as doses de composto orgânico foram: 0, 10, 20, 30, 40 e 50 t ha-1. Foi realizada uma colheita, aos 150 dias após o transplante das mudas. O óleo essencial foi extraído por hidrodestilação e analisado em cromatógrafo a gás acoplado a espectrômetro de massas (Shimadzu, QP-5000). Todos os resultados foram submetidos à análise de variância pelo teste F seguido da análise de regressão e o teste Tukey para os dados: massa seca útil da parte aérea, teor e produtividade do óleo essencial. Para as variáveis massa seca total e massa seca útil da parte aérea, as dosagens estudadas influenciaram as plantas, que apresentaram os melhores resultados na dose 50 t ha-1. Para teor de óleo não houve influência significativa para as dosagens estudadas, porém a dose 30 t ha-1 apresentou o melhor resultado. Entretanto para a produtividade do óleo essencial, as dosagens estudadas influenciaram as plantas, que na dosagem 30 t ha-1 obtiveram os melhores resultados.The objective was to evaluate the characteristics of the Baccharis dracunculifolia DC., depending on levels of organic fertilizer, and seedlings were used B. dracunculifolia produced by seed, and kept under shade for a period of 84 days before being transplanted to the field, spaced 1.0 x 1.0 m, with drip irrigation. The experimental design was randomized blocks with four replications, and doses of organic compost, 0, 10, 20, 30, 40 and 50 t ha-1. We performed a harvest, 150 days after transplanting. The essential oil was extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometer (Shimadzu, QP-5000). All results were submitted to analysis of variance F test followed by regression analysis and Tukey test for the data: useful dry mass of shoots, content of essential and productivity of essential oil. For the variables total dry mass and dry mass of shoots useful, the doses studied influenced the plants, which showed the best results at a dose 50 t ha-1. For content of essential oil no significant influence was verified on the doses studied, but the dose 30 t ha -1 showed the best result. However the productivity of the essential oil, the doses studied influenced the plants, which in dose 30 t ha-1 obtained the best results