DORMANCY AND GERMINATION OF REDROOT PIGWEED SEED (AMARANTHUS RETROFLEXUS L.)

Cilj rada bio je utvrditi utjecaj različitih metoda na prekid dormantnosti sjemena oštrodlakavog šćira (Amaranthus retroflexus L.), te utjecaj dubine sjetve sjemena šćira na klijavost i rast klijanaca. Uz kontrolni tretman, primijenjeno je pet tretmana za prekid dormantnosti sjemena: potapanje sjemena u destiliranu vodu na 24 sata, potapanje sjemena u otopinu KNO3 u koncentracijama od 0,2%, 1% i 2% tijekom 24 sata, stratifikacija sjemena na 5 °C tijekom 12 dana. Klijavost sjemena u kontrolnom tretmnu bila je najniža i iznosila je 4,5%. Svi primijenjeni tretmani imali su značajan utjecaj na povišenje klijavosti sjemena, a najviša klijavost utvrđena je u tretmanu s 2% otopinom KNO3 (31,7%) koji se pokazao najboljim za prekid dormantnosti. Stratifikacija sjemena i dvije više koncentracije KNO3 imale su značajan utjecaj na svježu masu klijanaca. Svi tretmani, osim potapanja sjemena u destiliranu vodu, utjecali su na duljinu klijanaca šćira. Sjeme šćira nicalo je bolje pri plićoj sjetvi (1 cm), no ne značajno u odnosu na veću dubinu (3 i 5 cm). S druge strane, duljina klijanaca i njihova svježa masa povećale su se s dubinom sjetve.The aim of study was to determine effects of different methods on breaking seed dormancy of redroot pigweed (Amaranthus retroflexus L.), and influence of seed's sowing depth on germination and seedling growth. Beside control treatment, five more treatments were applied for breaking seed dormancy: seed immersion in distilled water for 24 hours, seed immersion in 0.2%, 1% and 2% solution of KNO3 for 24 hours, cold seed stratification at 5ºC for 12 days. The lowest seed germination was recorded in control treatment and amounted to 4.5%. All treatments significantly increased seed germination, but 2% KNO3 solution provided the highest germination percentage (31.7%) and proved to be the best treatment for breaking seed dormancy. Cold seed stratification and two higher KNO3 concentrations had significant effect on seedlings fresh weight. All treatments, except distilled water seed immersion, had influence on redroot pigweed seedling length. Pigweed seeds had better emergence percentage at lower sowing depth (1cm), but not statistically compared to higher sowing depth (3 and 5 cm.). On the other hand, seedlings length and fresh weight increased with the depth of sowing