Estructura genética y diversidad de linajes de Pyricularia grisea en la zona arrocera venezolana

the genetic structure and lineage diversity of pyricularia grisea in the venezuelan rice zone were characterized using 448 monosporic isolates of p. grisea from commercial varieties, experimental lines, foreign varieties and international differential lines grown in plots during 1998, 1999 and 2000, in the barinas, cojedes, guarico and portuguesa states. characterization was made by polymerase chain reaction amplification using primers pot2-1 and pot2-2. seven lineages were identified as ven-1, ven-2, ven-3, ven-4, ven-5, ven-6 and ven-7. the study of the genetic relations between the lineages of p. grisea generated three homogenous groups, the first formed by ven-5, the second formed by the lineages ven-2, ven-3, ven-4 and ven-7, and the third by the lineages ven-1 and ven-6. frequency counts were of 76.34, 11.16, 5.58, 2.01, 2.23, 1.56 and 1.12% for ven-1 to ven-7, respectively. the equitability index fit by resampling techniques identifies the state of guarico as the "hot spot site".