A, The Evaluating Allelopathic potential of aqueous extracts of Sow thistle (Sonchus oleraceus L.) on emergence and seedling growth of Red rice (Oryza punctata)
Chemical weed control method caused environmental hazards and residual effects in crops and soil. Alternate approach to control weeds is getting attentions in sustainable production system. Use of aqueous extracts of weed is getting scientific attention as eco-friendly alternative to chemical herbicides especially under scenario of fast increasing herbicide resistance in weeds. To investigate the herbicidal potential of aqueous extract of winter weed of Sonchus oleraceus L. (Sow thistle) on summer weed Oryza punctate L. (red rice) seed emergence and initial seedling growth, a study was planned. In this study, seeds of O. punctate were incubated in seven concentrations (0, 0.25, 0.50, 1, 2, 4, and 8%) of different parts i.e. leaves, stem, flower of S. oleraceus. All the tested concentrations of various plant parts of S. oleraceus significantly inhibited the mean emergence time, emergence index, emergence percentage (%), time taken to 50% emergence as well as growth of O. punctata weed. However, maximum mean emergence time (5.26 days), minimum germination index (1.69), germination percentage (40%), root length (2.04 cm), shoot length (5.71 cm), fresh weight (59 g), dry weight (4.06 g) was noted at 8% concentration with fruit aqueous extract of S. oleraceus. Seed of O. punctata take maximum time to complete 50% emergence (3.33 days) under control where we applied distilled water. Results suggested fruit extract of S. oleraceus at 8% concentration can be used potential bio-herbicide for the control of O. punctate.
Key words: Chemical, eco-friendly, herbicidal potential, fruit extract