Effects of weed extracts on germination and seedling growth of some vegetable crops

Abstract

Chapra (Eleusine indica), Mutha (Cyperus rotundus) and Durba (Cynodon dactylon) are common weeds causing growth inhibition in crops. Therefore, their inhibitory effect on different crop species needs to be evaluated. A bioassay was carried out in the Plant Ecology Laboratory, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh to evaluate the allelopathic effects of the aqueous weed extracts on the germination and seedling growth of vegetable crops like red amaranth, radish and tomato during the period from July to November 2011. Hundred grams each of the weeds was chopped into small pieces and was made paste in mortar and pestles separately to extract them with distilled water having absolute weed extract volume of 100ml (100% conc.). Thus, the treatments were i) the absolute weed extract (100%) from each weed and its dilution with distilled water to ii) 12%, iii) 25% and iv) 50% along with control v) distilled water only. The experiment was laid out following completely randomized design (CRD) where each treatment was replicated five times. Germination percentage in all the test crops was significantly inhibited by the extracts in a concentration dependent manner. The germination of the seed and seedling growth were decreased with increase in concentration of the extracts and the highest inhibitory effect was observed in 100% concentration. Among the weed extract, mutha showed more inhibitory effect on seed germination and seedling growth of the test crops than other weed extracts and tomato seedlings were most sensitive to the extract.