ALLELOPATHIC EFFECT OF THREE WEED SPECIES ON GERMINATION AND GROWTH OF ONION CULTIVARS

Cilj istraživanja bio je ispitati alelopatski potencijal korovnih vrsta oštrodlakavi šćir (Amaranthus retroflexus L.), crna pomoćnica (Solanum nigrum L. emend. Miller) i divlji sirak (Sorghum halepense (L.) Pers.) na klijavost i rast dva kultivara luka (Holandski žuti i Srebrenac majski). Utjecaj vodenih ekstrakata od suhe nadzemne mase korova u koncentracijama od 1, 5 i 10% (10, 50 i 100 g/l) ispitan je u laboratorijskim uvjetima u petrijevim zdjelicama. Rezultati su pokazali da su vodeni ekstrakti značajno smanjili klijavost, duljinu korijena i izdanka te svježu masu klijanaca luka. Ekstrakti A. retroflexus i S. nigrum imali su jači inhibitorni učinak te su smanjili rast klijanaca preko 50%. Ekstrakti viših koncentracija (5 i 10%) pokazali su veći inhibitorni učinak. Zabilježene su razlike u osjetljivosti kultivara luka na učinak ekstrakata, pa je kod kultivara Holandski žuti zabilježeno veće smanjenje klijavosti i svježe mase klijanaca.The aim of the research was to determine allelopathic potential of weed species redroot pigweed (Amaranthus retroflexus L.), black nightshade (Solanum nigrum L. emend. Miller) and johnsongrass (Sorghum halepense (L.) Pers.) on germination and growth of two onion cultivars (Holandski žuti and Srebrenac majski). Effect of water extracts from dry aboveground weed biomass in concentrations of 1, 5 and 10% (10, 50 and 100 g/l) was examined under laboratory conditions in petri dishes. The results showed that all extracts significantly decreased germination, root and shoot length and fresh weight of onion seedlings. A. retroflexus and S. nigrum extracts had greater inhibitory potential and reduced seedlings growth over 50%. Extracts in higher concentrations (5 and 10%) exhibited higher inhibitory effect. Differences in sensitivity among onion cultivars were recorded, and inhibition of germination and fresh weight of seedlings was greater in Holandski žuti cultiva