Influence of selected environmental factors on seed germination and seedling emergence of Dinebra panicea var. brachiata (Steud.)

Dinebra panicea var. brachiata (Steud.) is related to genus Leptochloa., some species of which are significant rice crop weeds However, little is known about how D. panicea responds to various environmental cues. This study investigates the effects of temperature, light, salt stress, moisture stress, pH, heat shock, smoke, and burial depth on seeds collected in successive years (2015 and 2016) from Queensland, Australia. Seed germination was higher overall for older seeds (2015) compared to younger (2016) at 30/20 degrees C and 25/15 degrees C, but there was less difference between light treatments (12 L/D, 24D) in both temperature ranges for older seeds compared to younger. Increasing moisture and salt stress gradually reduced germination, germination was high over the pH range from pH 4 to pH 10, short term (three minutes) heat exposure to 80 degrees C or less did not inhibit germination, but there was no significant difference between years for any of these environmental cues. Germination was greatly reduced at 100 degrees C and eliminated at 120 degrees C. Smoke significantly inhibited germination. Seeds from both years germinated on the soil surface and emerged from 0.2 cm, with no emergence from deeper than 0.5 cm. The data collected from this study may assist land managers to manage infestations of this weed.