RESUMO
ABSTRACT: Euphorbia cyathophora Murray is a plant species with medicinal and ornamental potential but whose in vitro propagation is unknown. Two experiments were performed to know 1) the effect of light (WL) at 25±2 °C and 20 μmol m-2 s-1 luminous intensity, or darkness at 20±2 °C, for the first 20 days and subsequent placement in light (DKL) as previously described, and 2) the best combination of plant growth regulators: benzyl amino purine (BAP), kynetin (KIN), 2-isopentenyl adenine (2iP) and thidiazuron (TDZ) in combination with naphthaleneacetic acid (NAA) and the effect of both light conditions. The DKL treatment did not promote the growth of leaves, cotyledons, or plantlet height; in contrast, WL produced a more developed root system with early appearance of tertiary roots. In regards to the interaction of plant regulators and light effect, only the treatment with 1 mg BAP L-1 and 0.1 mg NAA L-1 generated shoots in both light conditions (DKL and WL). Darkness (DKL) generated more indirect greatest morphogenic responses (callus formation).
RESUMO: Euphorbia cyathophora Murray é uma espécie vegetal com potencial medicinal e ornamental, mas cuja propagação in vitro é desconhecida. Dois experimentos foram realizados para conhecer 1) o efeito da luz (WL) a 25±2 °C e 20 μmol m-2 s-1 intensidade luminosa, ou escuridão a 20±2 °C, nos primeiros 20 dias e posterior colocação em luz (DKL) como descrito anteriormente, e 2) a melhor combinação de reguladores de crescimento vegetal: benzil amina purina (BAP), kynetina (KIN), 2-isopentenil adenina (2iP) e thidiazuron (TDZ) em combinação com ácido naftalenoacético (ANA) e o efeito de ambas as condições de luz. O tratamento com DKL não promoveu o crescimento de folhas, cotilédones ou altura das plântulas. Em contraste, a WL produziu um sistema radicular mais desenvolvido com o aparecimento precoce de raízes terciárias. Com relação à interação dos reguladores vegetais e efeito luminoso, apenas o tratamento com 1 mg de BAP L-1 e 0,1 mg de NAA L-1 gerou brotações em ambas as condições de luz (DKL e WL). Escuridão (DKL) gerou mais respostas morfogênicas mais diretas (formação de calo).
RESUMO
Fruit rot is the principal phytopathological problem of pipiana pumpkin (Cucurbita argyrosperma Huber) in the state of Guerrero. The aims of this research were to 1) identify the causal agent of southern blight on pumpkin fruits by morphological, pathogenic, and molecular analysis (ITS1, 5.8S, ITS2); 2) evaluate in vitro Trichoderma spp. strains and chemical fungicides; and 3) evaluate under rainfed field conditions, the strains that obtained the best results in vitro, combined with fungicides during two crop cycles. Number of commercial and non-commercial fruits at harvest, and seed yield (kg ha-1) were registered. Morphological, pathogenic and molecular characterization identified Sclerotium rolfsii as the causal agent of rot in pipiana pumpkin fruits. Now, in vitro conditions, the highest inhibition of S. rolfsii were obtained by Trichoderma virens strain G-41 (70.72%), T. asperellum strain CSAEGro-1 (69%), and the fungicides metalaxyl (100%), pyraclostrobin (100%), quintozene (100%), cyprodinil + fludioxonil (100%), and prochloraz (100%). Thiophanate-methyl only delayed growth (4.17%). In field conditions, during the spring-summer 2015 cycle, T. asperellum strain CSAEGro-1 + metalaxyl, and T. asperellum + cyprodinil + fludioxonil, favored the highest number of fruits and seed yield in the crop.
