Germination ecology of Coronopus didymus in western region of Haryana.
Coronopus didymus (lesser swinecress) is an invasive weed throughout the globe. The experiments were conducted in order to ascertain the effects of different environmental factors on C. didymus germination and emergence process. Its highest germination (53%) was obtained at 15/10°C (day/night). But it decreased with increasing temperature, and failed to germinate at 45/35°C. Germination decreased considerably from 40 to 8% (0 to -0.8 MPa) and inhibited completely at -1.0 and -1.2 MPa osmotic potential. There was 50% reduction in maximum germination as salinity increased from 0 to 50 mM NaCl. It could prefer acidic conditions rather than basic conditions. It was non-photoblastic in nature, as dark and light period had no significant effect on its germination. The optimal seeding depth for maximum emergence was 0.5 cm (>80%), but its emergence decreased as seeding depth increased further. Mulching showed inhibitory action on its emergence. Continuous flooding for different durations significantly increased seedling emergence of C. didymus over no-flooding condition. As after 32 days of continuous flooding, its emergence was 100%. The information obtained from this study would help in predicting potentials and requirements of ecological environments of this weed species and in developing effective and sustainable weed management measures against this weed.