An evaluation of methods for breaking seed dormancy in kudzu (Pueraria lobata)

We evaluated several methods for breaking dormancy in seeds of the invasive weed Pueraria lobata (Willd.) Ohwi (kudzu). Seedlings from untreated seeds emerged from late March to early October 1999 in trays placed outdoors und er natural weather conditions; mean cumulative percentage emergence was low (11%). In growth chamber experiments, germination percentages of untreated seeds ranged from 6 to 17%. All hand-scarified seeds germinated, whereas o nly 6% of intact seeds germinated. Other dormancy-breaking methods that pro duced higher germination percentages included exposure to ethyl alcohol for 6-12 h (24-86%), exposure to concentrated sulfuric acid for 1-2 h (65-81%) , and exposure to moist heat for 5-300 s (30-80%). The influence of tempera ture on germination percentages of seeds following dry heat treatments depe nded on the duration of exposure. At 60 and 80 degreesC, germination percen tages increased with longer exposures to dry heat and were greatest after 7 20 min (27 and 60%, respectively). At 100 degreesC, percent germination was greatest when seeds were exposed to dry heat for only 10 min (93%). Cold s tratification at 5 degreesC for 0-6 weeks did not increase seed germination percentages after exposure to a range of alternating thermoperiods. Simila rly, dry storage at room temperature for 0, 200, or 400 days did not affect germination percentages in light or dark treatments.