Germination and seedling vigour of some major crop plants as influenced by allelopathy of Sphaeranthus Indicus

The effect of different concentrations of capitula extract of Sphaeranthus indicus on seed germination and early seedling growth of Oryza sativa, Triticum aestivum and Vigna radiata (L.) Wilczek was examined. Germination per cent and seedling growth were decreased with increase in concentration of extract, indicating concentration dependency. The highest concentration (100 g l⁻¹) resulted in 80 per cent decrease in seed germination, 94.4 per cent decrease in root length and 83.3 per cent decrease in shoot length in O. sativa. In T. aestivum, the decrease in seed germination, root length and shoot length was 60, 93 and 84.9 per cent, respectively. These values were in order of 22.2, 71.6 and 80 per cent in V. radiata. The results of the study suggest that the capitula extract of S. indicus contains water soluble compounds which are phytotoxic in nature. Phyto-chemical analysis identified capitula extract as alkenes and aldehydes.