POTENCIAL ALELOPÁTICO DE EXTRATOS AQUOSOS DE GENÓTIPOS DE CANOLA SOBRE Bidens pilosa 1 Allelopathic Potential of Aqueous Extracts of Canola Genotypes on Bidens Pilosa

RESUMO - O objetivo deste trabalho foi avaliar o efeito de extratos aquosos de plantas degenotipos de canola na germinacao e comprimento da radicula de picao-preto ( Bidens pilosa ).Os tratamentos estudados foram constituidos dos genotipos de canola Hyola 420, Hyola401, Hyola 43, Hyola 60, Hyola 61, Y 3000, H 1432, Dln 03-02, Dln 03-04, Sdh 03-01, Sdh 03-07, Sw-2797 e Sw-Eclipse, nas concentracoes de extrato aquoso a 100, 75, 50, 25 e 0%. Odelineamento experimental foi inteiramente casualizado, em esquema fatorial com doisfatores 12 x 4 (genotipos e concentracao do extrato), com quatro repeticoes. O experimentofoi conduzido em caixas gerbox com papel de germinacao embebido nos extratos das plantasde canola, sobre os quais foram dispostos aquenios de picao-preto. Sete dias apos asemeadura, avaliou-se o numero de aquenios germinados e o comprimento das radiculas.Os resultados revelaram que os extratos de canola influenciam negativamente a germinacaode aquenios e o comprimento da radicula de Bidens pilosa. Para alguns genotipos, as baixasconcentracoes de extratos estimularam tanto o crescimento da radicula quanto aporcentagem de germinacao dos aquenios; em altas concentracoes, os genotipos nao diferiramna germinacao dos aquenios e no comprimento da radicula.Palavras-chave: alelopatia, picao-preto, Brassica napus , oleifera.ABSTRACT - The objective of this experiment was to evaluate the effect of aqueous extract ofplants of canola genotypes on the germination and radicle length of hairy beggartick (Bidenspilosa). The treatments consisted of genotypes of canola Hyola 420, Hyola 401, Hyola 43, Hyola60, Hyola 61, Y 3000, H 1432, Dln 03-02, Dln 03-04, Sdh 03-01, Sdh 03-07, sw-2797, and Sw-Eclipse. The concentrations of aqueous extract of 100, 75, 50, 25 and 0 % were tested. A completelyrandomized experimental design was used in a factorial 12 x 4 (genotypes and extractconcentrations) with four replications. The experiment was carried out in plastic boxes containingot the bottom blotter paper moistened with the aqueous extract, where the hairy beggartick acheneswere seeded. Seven days later, the number of germinated achenes was evaluated and the lengthof radicles measured. The results showed that the canola extracts negatively influenced achenegermination and radicle length. The effects increased with increased extract concentrations. Atlow concentration, some genotype extracts presented a stimulating effect. The results showedthat the variability among canola genotypes was only evident at low extract concentrations.Keywords: alellophaty, hairy beggartick, Brassica napus , oleifera.