Temperature effects on Eleusine indica and Setana anceps grown in association (I)

Studies were made at Kairi on the Atherton Tableland of Queensland, Australia, on the effects of varying lemperature regimes, both controlled and natural, on the germination of seed of Setaria antcept Stapf. cv. Nandi and Eleusine indica (L.) Gaertn. The germination of E. indica seed was found to be much more temperature labile than that of S. ancepts. The temperature required for peak germination was higher for E. indica seed than for S. ancepts seed. The effects of temperature on competition between E. indica and S. ancepts were studied in the field by varying the time of planting. It was shown that at mean screen temperatures measured throughout the growth period of <23° C, S. ancepts was dominant in mixtures of the two species. At mean temperatures >23° C E. indica was dominant. There was a tendancy for S. aweps yields to decline with increase in E. indica plant density but there was a much closer negative correlation between E indica top dry weight and S. aancepts yield. From the meteorological data for Kairi for the past 25 years predictions were made on the best times to plant S. ancepts to avoid serious competition from E indica.