2305-0683 2305-0683 S2305-06832017000100049 10.18004/investig.agrar.2017.junio.49-55 Brazil 00 06 2017 00 06 2017 19 1 49 55

2000 56 197- 204 2006 30 605-14 1996 20 175-82 1979 262 2006 5 1 1 26-32 2007 2007 Gramado, RS 5 2002 26 9-15 1997 61 239-24