ABSTRACT:We determined the inhibitory allelopathic effects of the volatile extracts of Cinnamomum zeylanicum Ness, Lippia sidoides Cham. and Cymbopogum nardus L. on seed germination and root growth of seedlings of Bidens pilosa. The experiment was conducted at the Seed Analysis Laboratory of the Department of Plant Science, Federal University of Ceará. For this end, we used oils at the concentrations of 0.01, 0.02, 0.04 and 0.08% (v/v). Five treatments were used for each of the oils arranged in a completely randomized design with four replications of 25 seeds. The seeds were sown in Petri dishes lined with filter paper moistened with distilled water and, aiming at the indirect contact with each oil, two sheets of filter paper were placed on top of the lid, in which three (3) mL of each oil solution were added. Then, the dishes were incubated in a germination chamber at 25°C. The pH did not contribute to alter the results; the volatile extracts of essential oils of C. zeylanicum, L. sidoides and C. nardus inhibited seed germination and root growth of seedlings of B. pilosa, which shows allelopathic potential; and the concentration of 0.08% of oils caused the overall deterioration of the roots and death of seedlings of B. pilosa.Key words: allelopathy, Cinnamomum zeylanicum Ness, Cymbopogum nardus L., herbicides, Lippia sidoides Cham. Foram utilizados cinco tratamentos para cada óleo dispostos em delineamento inteiramente casualizado com quatro repetições de 25 sementes. As sementes foram semeadas em placas de Petri forradas com papel de filtro umedecido com água destilada e, visando o contato indireto com cada óleo, foram colocadas duas folhas de papel de filtro na parte superior interna da tampa, onde foi adicionado 3(três) mL da solução de cada óleo. Em seguida, as placas foram incubadas em câmara de germinação a 25ºC. O pH não contribuiu para alterar os resultados; os extratos voláteis de óleos essenciais de C. zeylanicum, L. sidoides and C. nardus inibiram a germinação de sementes e o crescimento da raiz de plântulas de B. pilosa, evidenciando potencial alelopático; a concentração de 0,08% dos óleos causaram a deterioração total das raízes e morte das plântulas de B. pilosa. RESUMO: Efeito Alelopático de oleos essencias de plantas medicinais em

RESUMO: A redução na altura da planta e obtenção de resistência às doenças foi experimentada através da indução de mutação por raios-gama na variedade de trigo (Triticum aestivum L.) IAC-17. Sementes foram irradiadas com 35 krad e a partir da geração M 2 iniciou-se a seleção. Três das linhagens selecionadas foram comparadas com o cultivar original IAC-17, durante três anos, em sete ensaios avançados realizados em vários locais, em condição de sequeiro e irrigação. Os resultados demonstraram a obtenção de um mutante que apresentou redução na altura da planta, tendência de sofrer menos acamamento e maior resistência a oídio (Erysiphe graminis f. sp. tritici). As demais características agronômicas avaliadas, tais como produção de grãos e seus componentes, reação ao Helminthosporium sativum, causador da mancha das folhas, reação a Puccinia graminis f. sp. tritici (ferrugem do colmo) e P. recôndita (ferrugem da folha), tolerância a alumínio e ciclo permaneceram inalteradas em relação a IAC-17. Os resultados indicaram a utilidade da indução de mutações por raios gama para a correção de defeitos de caracteres de herança simples em variedades elites. Descritores: Raios-gama; mulantes; melhoramento de trigo REDUCTION OF PLANT HEIGHT AND DISEASE RESISTANCE THROUGH MUTATION BREEDING OF WHEAT (Triticum aestivum L.) IAC-17ABSTRACT: The objective of the present research was to obtain mutants with reduced plant height and resistance to diseases in wheat (Triticum aestivum L.), variety IAC-17, through gamma-irradiation. Seeds were irradiated with gammarays (35 krad) and the selection was started in the M 2 generation. Three selected lines were compared to the control IAC-17 during three years, in seven trials carried out in several localities under or without irrigation. One mutant line showed significant reduction in plant height, less lodging and increased resistance to powdery mildew (Erysiphe graminis f. sp. tritici) This mutant also showed the same yield, yield components, tolerance to aluminium, cycle and reaction to Helminthosporium sativum, Puccinia graminis f. sp. tritici, P. recondita as the original variety. The results indicated the usefulness of the mutation breeding method to correct defects of simple inherited characters in oustanding commercial varieties.

Some plant species from Cerrado were considered to have allelopathic effects. Allelopathy means the chemical competitionbetween plants wich can benefit or harm another plant. The objective of this study was to determine the effect ofhydrophilic gel from the second layer of Magonia pubescens St. Hil. seeds (a high plant, known as Tingui, that grows inthe areas of Cerrado) on germination and early development of cucumber (Cucumis sativus L.). The cucumber seeds weretreated with a mixture of sand and powder of Tingui in different proportions of 25%, 50%, 75% and 100%. The sand waspreviously washed with tap water, then with distilled water and, after that, it was dried in an oven at 100 ºC for 5 hours.The seeds were planted in 50 ml polystyerenes cups and moistened with water daily. To check possible changes from theprocess, a batch of seed were tested under the same conditions without the Tingui powder (only with sand). The parametersof this study were to measure the seed germination and plant development. The growth period was seven days, under± 30 ºC, and 12 hours photoperiod. The overall data were analyzed using ANOVA and Scheffe test, at 5% significancelevel. From the results, we concluded that there were no differences in the percentage of seed germination for all treatments,except the treatment of 100%. As for the germination average time and the seed growth, there were no significantdifferences between the treatment of 25% and the control, but the effects were more effective at higher concentrations.

Some plant species from Cerrado were considered to have allelopathic effects. Allelopathy means the chemical competitionbetween plants wich can benefit or harm another plant. The objective of this study was to determine the effect ofhydrophilic gel from the second layer of Magonia pubescens St. Hil. seeds (a high plant, known as Tingui, that grows inthe areas of Cerrado) on germination and early development of cucumber (Cucumis sativus L.). The cucumber seeds weretreated with a mixture of sand and powder of Tingui in different proportions of 25%, 50%, 75% and 100%. The sand waspreviously washed with tap water, then with distilled water and, after that, it was dried in an oven at 100 ºC for 5 hours.The seeds were planted in 50 ml polystyerenes cups and moistened with water daily. To check possible changes from theprocess, a batch of seed were tested under the same conditions without the Tingui powder (only with sand). The parametersof this study were to measure the seed germination and plant development. The growth period was seven days, under± 30 ºC, and 12 hours photoperiod. The overall data were analyzed using ANOVA and Scheffe test, at 5% significancelevel. From the results, we concluded that there were no differences in the percentage of seed germination for all treatments,except the treatment of 100%. As for the germination average time and the seed growth, there were no significantdifferences between the treatment of 25% and the control, but the effects were more effective at higher concentrations.

<p>O presente trabalho foi desenvolvido em condições de casa de vegetação situada em Parnaíba-PI, município onde predominam altas temperaturas. Objetivou-se avaliar a germinação de diferentes lotes de sementes de alface antes e após a embebição em solução de hipoclorito de sódio (NaCIO). O delineamento experimental foi em blocos casualisados, com os tratamentos dispostos em arranjo fatorial 2 x 7 (duas variáveis como pré-germinativos: com imersão em NaClO e sem imersão em NaClO, e sete cultivares de alface), com quatro repetições. As variáveis analisadas foram: Primeira contagem do teste de germinação (PCG), Teste de germinação (TG) e Índice de velocidade de germinação (IVG). Analisando-se os dados obtidos, verificou-se que independente da presença ou ausência do tratamento pré-germinativo, a cultivar T6 foi a que apresentou os melhores resultados para as variáveis analisadas. Exceto T2, todas as outras cultivares que receberam tratamento com hipoclorito de sódio (NaClO) obtiveram resultados expressivos, em comparação com as que não receberam esse tratamento, entretanto, a germinação de todos os lotes foi inferior ao estabelecido para comercialização de sementes de alface, com recomendações acima de 80%. </p><p align="center"><strong><em>Influence of NaClO on lettuce seed germination in Parnaíba-PI</em></strong></p><p><strong>Abstract</strong><strong>: </strong>The present study aimed to evaluate, under conditions of a greenhouse located in Parnaiba, PI, where high temperatures and after soaking in solution of sodium hypochlorite (NaCIO), the germination of seeds of seven cultivars of lettuce. The experimental design was of randomized blocks, with treatments arranged in factorial arrangement 2 x 7 (two variables as pré-germinativos: with NaClO and immersion without immersion in NaClO, and seven cultivars of lettuce), with four replicates. The seeds were subjected to the following determinations: First germination test score (PCG), germination test (TG) and germination speed Index (IVG). Analyzing the data obtained, it was found that regardless of the presence or absence of treatment pre-germinative, cultivating T6 was presented the best results for the variables analyzed. Except for T2, all other cultivars that received treatment with sodium hypochlorite (NaClO) achieved significant results, compared to those who did not receive this treatment, however, the germination of all batches was lower than that established for commercialization of seeds of lettuce, with recommendations above 80.</p>