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Pudumi Rongpipi, Zenwang Konyak* and Keneizoulhou Kesiezie
Department of Botany, Kohima Science College, Jotsoma 797002, India
Email: zenwangnaga@gmail.com
Received-01.08.2026, Revised-11.08.2026, Accepted-29.08.2026
Abstract: Weeds may affect crop establishment not only through competition for resources but also through chemical interactions. This study evaluated the effects of aqueous leaf extracts of Ageratum conyzoides L. and Bidens pilosa L. on seed germination and early seedling growth of two locally cultivated rice genotypes, Thevür and Rosolha. A factorial experiment was conducted in a completely randomized design with three replications. Root length (RL), shoot length (SL), root-to-shoot ratio (R/S), seedling vigor index (SVI), total seedling length (TSL), mean germination time (MGT) and germination percentage (GP) were evaluated. Extract concentration significantly affected SL, RL, R/S, SVI, TSL and MGT (P < 0.001), whereas GP was not significantly affected. Rosolha showed greater RL, R/S and SVI than Thevür (P < 0.001). Across weed species, seedlings exposed to B. pilosa had greater RL, R/S and SVI than those exposed to A. conyzoides, indicating stronger growth inhibition by A. conyzoides under the conditions tested. Significant genotype × concentration interactions were observed for SL (P < 0.001), TSL (P = 0.002) and MGT (P = 0.020), with reductions in growth and greater delays in germination at higher concentrations being more pronounced in Thevür. A significant weed species × concentration interaction was also observed for MGT (P = 0.042). Overall, the responses of the two rice genotypes to aqueous leaf extracts depended strongly on extract concentration, with Thevür showing greater reductions in early seedling growth at higher concentrations.
Keywords: Angami, Allelopathy, Wet terrace rice, Weeds, Aqueous leaf extract
REFERENCES
Abdul-Baki, A.A. and Anderson, J.D. (1973). Vigor determination in soybean seed by multiple criteria. Crop Science, 13(6), 630-633.
Akter, P., Ahmed, A.M.A., Promie, F.K. and Haque, M.E. (2023). Root exudates of fifteen common weed species: Phytochemical screening and allelopathic effects on Triticum aestivum L. Agronomy, 13(2): 381.
An, M., Pratley, J.E., Haig, T. and Liu, D.L. (2005). Whole-range assessment: a simple method for analysing allelopathic dose-response data. Nonlinearity in Biology, Toxicology, Medicine, 3(2), 245-260.
Bandeira, A. da S., Boaventura, C., Gugé, R. M. A., Amaral, M. C. A., Castro Filho, M. N. de, Cardoso, A. D. and Fernandes, N. de S. (2024). Allelopathic potential of Bidens pilosa L. extracts on seed germination and seedling development of lettuce and chicory. Revista de Ciências Agroveterinárias, 23(4), 581-587.
Bhatt, B. P., Tomar, J. M. S. and Misra, L. K. (2001). Allelopathic effects of weeds on germination and growth of legumes and cereal crops of North Eastern Himalayas. Allelopathy Journal, 8(2), 225-232.
Chopra, N., Tewari, G., Tewari, L. M., Upreti, B. and Naveen Pandey, P. (2017). Allelopathic Effect of Echinochloa colona L. and Cyperus iria L. Weed Extracts on the Seed Germination and Seedling Growth of Rice and Soyabean. Advances in Agriculture, Vol 2017. ID 5748524. 5 pages.
Dass, A., Shekhawat, K., Choudhary, A. K., Sepat, S., Rathore, S. S., Mahajan, G. and Chauhan, B. S. (2017). Weed management in rice using crop competition-A review. Crop Protection, 95, 45-52.
Ellis, R. H. and Roberts, E. H. (1981). The quantification of ageing and survival in orthodox seeds. Seed Science and Technology (Netherlands), 9(2), 373-409.
Haugland, E. and Brandsaeter, L. O. (1996). Experiments on bioassay sensitivity in the study of allelopathy. Journal of Chemical Ecology, 22(10), 1845-1859.
Horvath, D. P., Clay, S. A., Swanton, C. J., Anderson, J. V. and Chao, W. S. (2023). Weed-induced crop yield loss: A new paradigm and new challenges. Trends in Plant Science, 28(5), 567-582.
Hsueh, M.T., Fan, C. and Chang, W.L. (2020). Allelopathic effects of Bidens pilosa L. var. radiata Sch. Bip. on the tuber sprouting and seedling growth of Cyperus rotundus L. Plants, 9(6), 742.
Kaur, S., Kaur, R. and Chauhan, B. S. (2018). Understanding crop-weed-fertilizer-water interactions and their implications for weed management in agricultural systems. Crop Protection, 103, 65-72.
Khanh, T. D., Cong, L. C., Xuan, T. D., Uezato, Y., Deba, F., Toyama, T. and Tawata, S. (2009). Allelopathic plants: 20. Hairy beggarticks (Bidens pilosa L.). Allelopathy Journal, 24(2), 243-254.
Khasabulli, B. D., Musyimi, D. M., George, O. and Gichuhi, M. N. (2018). Allelopathic effect of Bidens pilosa on seed germination and growth of Amaranthus dubius. Journal of Asian Scientific Research, 8(3), 103-112.
Kong, C., Hu, F., Liang, W. and Zhang, C. (2004). Allelopathic Plants. Ageratum conyzoides L. Allelopathy Journal, 14(1), 1-12.
Konyak, Z., Kire, K. and Thyü, G. (2022). Checklist of weeds growing in wet terraced rice (Oryza sativa L.) fields in Jotsoma area of Kohima district of Nagaland, India. Pleione, 16(1), 12-18.
Krumsri, R, Suwunnamek, U, Homhaul, W, Laosinwattana, C. and Poonpaiboonpipattana, T. (2015). Allelopathic effects of Bidens pilosa var. radiata and its preliminary utilization to control weeds in rice. International Journal of Agricultural Technology, 11, 1875-1886.
Lalbiakdika, I., Lalnunmawia, F. and Lalruatsanga, H. (2022). Allelopathic effect of common weeds on germination and seedling growth of rice in wetland paddy fields of Mizoram, India. Plant, Soil and Environment, 68(8), 393-400.
Liu, X., Ye, Y., Yang, Z. and Zhang, Y. (2025). Allelopathic effects of dominant native invaders on forage establishment: implications for alpine meadow restoration on the Qinghai-Xizang plateau. Plants, 14(22), 3506.
Masum, S. M., Hossain, M. A., Akamine, H., Sakagami, J. I. and Bhowmik, P. C. (2016). Allelopathic potential of indigenous Bangladeshi rice varieties. Weed Biology and Management, 16(3), 119-131.
Negi, B., Bargali, S.S., Bargali, K. and Khatri, K. (2020). Allelopathic Interference of Ageratum conyzoides L. against Rice Varieties. Current Agriculture Research Journal, 8(2), 69-76.
Singh, A. A., Rajeswari, G., Nirmal, L. A. and Samuel, J. (2021). Synthesis and extraction routes of allelochemicals from plants and microbes: A review. Reviews in Analytical Chemistry, 40, 293-311.
Singh, H. P., Batish, D. R., Kaur, S. and Kohli, R. K. (2003). Phytotoxic interference of Ageratum conyzoides with wheat (Triticum aestivum). Journal of Agronomy and Crop Science, 189, 341-346.
Weston, L. A. and Duke, S. O. (2003). Weed and crop allelopathy. Critical Reviews in Plant Sciences, 22, 367-389.
Wu, A. P., Huang, Z., Miao, S. L. and Dong, M. (2010). Effects of Mikania micrantha extracts and their exposure time on seed vigor, seed germination and seedling growth of plants. Allelopathy Journal, 25(2), 503-512.
Yusoff, N. and Ismail, B.S. (2015). Allelopathic potential of Chromolaena odorata and Mikania micrantha on Brassica chinensis var. parachinensis. AIP Conference Proceedings, 1678, 020024.
Zumbado-Rodríguez, A., Portuguez-García, M. P. and González-Lutz, M. I. (2026). Allelopathy of Ageratum conyzoides L. on Bidens pilosa L., Oryza sativa L., and Cucumis sativus L. Agronomía Mesoamericana, 37, bc16e790.