Gamba grass (Andropogon gayanus Kunth.) seed persistence and germination temperature tolerance

摘要: Gamba grass (Andropogon gayanus Kunth.) is a highly invasive, naturalised Weed of National Significance in Australia due to its economic, environmental and social impacts. It outcompetes native pastures fuels intense fires northern Australian rangelands. To aid management current infestations better understand potential distribution, this study determined the germination response gamba under range constant (13°C-48°C) alternating (11/7°C-52/42°C) temperature regimes quantified longevity soil seed banks. The effect different types, levels pasture cover burial depths on was investigated Dry Tropics Queensland. Germination occurred wide both (17°C-39°C) day/night temperatures (16/12°C-47/39°C), although level declined at lower higher ranges. At cooler temperatures, viability not affected, but seeds went into state dormancy. highest recorded lowest regime (13°C) two (11/7°C 16/12°C). A gradual variable decline thereafter with increasing temperatures. (e.g. 39°C-43°C 47/39°C) dormancy loss were occurring, once reached above 47/39°C 43°C all rendered unviable after 9 6 weeks respectively. In Queensland, <1% 12 months nil 24 months, irrespective type or vegetation cover. However, depth had significant effect, surface located exhibiting faster rate than buried below ground (i.e. 2.5-10 cm). These findings have implications for duration control/eradication programs persistence) also suggest that has greatly expand distribution relatively southern latitude areas Australia.