Abstract The objective of this work was to evaluate the fungitoxic effect of the aqueous extracts of Baccharis trimera on the mycelial growth of Colletotrichum lindemuthianum 89 race, as well as its effect on the accumulation of phaseolin in hypocotyls of different cultivars and common bean varieties. It was obtained 20% aqueous extract from plants collected in municipalities of the Western Region of Paraná. Blocks containing C. lindemuthianum mycelium were transferred to Petri dishes containing medium with the different extracts and incubated at 25 °C. The colonies diameter was measured until the 12th day. Effects of aqueous extracts on phaseolin production was evaluated in hypocotyls of Carioca, Cnpf 8104, Soberana, Tibatã, Uirapurú cultivars, as well as Rosinha and Vermelho varieties. Each one cultivar and variety hypocotyl was transferred separately to test tubes containing 500 μL of 20% aqueous extracts. Sterile water, Bion®, and UV was used as controls. The phaseolin production was measured in spectrophotometer [280 nm]. Results of the evaluation of the antifungal activity of aqueous extracts of Baccharis sp. specimens collected indicate that approximately 50% of the samples presented capacity to reduce between 74 and 92% of C. lindemuthianum growth. Cultivar Tibatã and Vermelho variety showed greater sensitivity over the applied treatments. Results of fungal filtrates and vegetal aqueous extracts presented a low capacity to induce the production of phaseolin in hypocotyls.

Objetivou-se, no presente trabalho, avaliar o efeito do 2,4-D e do BAP na formação de protocormos a partir de regiões meristemáticas da raiz e segmentos foliares de Miltonia flavescens Lindl., bem como testar o efeito de concentrações de sacarose e níveis de pH no crescimento in vitro dos protocormos. Ápices radiculares e segmentos de folhas de plantas germinadas in vitro foram inoculados em meio de cultura MS/2 suplementado com 2,4-D e BAP onde permaneceram por 210 dias no escuro, sendo transferidos para a luz e inoculados em meio de cultura isento de reguladores, avaliando-se a porcentagem de explantes com protocormos e o número médio de protocormos regenerados por explante. A associação de 3 mg L-1 de 2,4-D e 1 ou 3 mg L-1 de BAP proporcionou os melhores resultados quanto à formação de protocormos. Esses foram cultivados em meio de cultura MS/2 onde testou-se o efeito da sacarose (0, 15, 30, 45 e 60 g L-1) e do pH (5.0, 5.8 e 6.6) sobre o seu crescimento. As concentrações de 15 e 30 g L-1 de sacarose independentes do pH, mostraram-se mais eficientes para o cultivo in vitro da espécie proporcionando a formação de um maior número e comprimento de raízes, altura de parte aérea e peso da matéria fresca. O pH só apresentou-se significativo quando em combinação com 15 g L-1 de sacarose para as variáveis comprimento da maior raiz e peso da matéria fresca.

The aim of the present work was to evaluate the effect of 2,4-D and BAP on the protocorm formation from meristematic areas of the root and leaf segments of Miltonia flavescens Lindl., as well as to test the effect of sucrose concentrations and pH levels on the in vitro growth of protocorms. Root apexes and leaf segments of in vitro-germinated plants were cultured on MS/2 culture medium supplemented with 2,4-D and BAP and kept in the dark for 210 days. Explants were then transferred to light and cultured on culture medium lacking growth regulators. Percentage of explants with protocorms and average number of protocorms regenerated per explant were evaluated. The combination of 3 mg L-1 2,4-D and 1 or 3 mg L-1 BAP provided the best results for protocorm formation. Protocorms were cultured on MS/2 culture medium to test the effect of sucrose (0, 15, 30, 45, and 60 g L-1) and pH (5.0, 5.8, and 6.6) on their growth. The concentrations of 15 and 30 g L-1 sucrose, independently of the pH, were more efficient for the in vitro culture of this species, promoting an increase in the number and length of the roots, plant height, and fresh weight. The pH was significant only in combination with 15 g L-1 sucrose for the variables length of the largest root and fresh weight.

Dentre as várias doenças que causam problemas no cultivo de feijão comum (Phaseolus vulgaris L.), uma das mais importantes é a antracnose causada pelo fungo Colletotrichum lindemuthianum (Saac. et Magn.) Scrib., a qual pode resultar em severas perdas na produtividade de grãos. O controle genético, nas cultivares diferenciais Michelite, Michigan Dark Red Kidney, Perry Marrow, Cornell 49-242, PI 207262, AB 136 e G 2333 e seus 21 híbridos dialélicos, foi obtido usando a metodologia de Hayman (1954). Todas as populações F1s foram avaliadas em relação à raça 89, enquanto que os híbridos envolvendo a cultivar G 2333 não foram avaliados com a raça 31. Os resultados demonstraram que os efeitos aditivos foram predominantes para a raça 31, enquanto os efeitos gênicos não aditivos foram mais importantes na reação de incompatibilidade das cultivares a raça 89. Os resultados ainda evidenciaram um elevado coeficiente de determinação genética para a raça 31. Os cultivares G 2333, AB 136 e PI 207262 são os mais indicados para programas de melhoramento visando à obtenção de cultivares resistentes à antracnose por possuírem maior proporção de alelos dominantes para resistência às raças 31 e 89.

The aim of this work was to perform genetic control on differential cultivars Michelite, Michigan Dark Red Kidney, Perry Marrow, Cornell 49-242, PI 207262, AB 136 and G 2333 and its diallel hybrids by using Hayman's methodology. The entire F1s populations were evaluated in relation to race 89, whereas the race 31, the diallel scheme did not include the cultivar G 2333. The results showed that the additive effects were predominant for the 31 race, while non-additive effects were more important for race 89. The results demonstrated a high coefficient of genetic determination for the race 31. The G 2333, AB 136 and PI 207262 cultivars should be recommended obtaining cultivar resistant to anthracnose by backcross programs because theyshowed the highest proportion of resistant dominant alleles for the races 31 and 89.