Assessment of genetic relationships among isolates of Macrophomina phaseolina using a simplified AFLP technique and two different methods of analysis

A simplified protocol for detecting amplified restriction fragment length p olymorphisms (AFLPs) was used to evaluate genetic diversity among isolates of Macrophomina phaseolina collected from different hosts and locations. Fi fteen different selective primer pairs were evaluated. No significant diffe rences were observed among primer pairs, grouped based on the AT% of the se lective nucleotides, for several parameters that define primer utility. Rel ationship matrices generated with each group of AFLP primers were highly co rrelated (r(2) > 0.92). Isolates were very diverse and could not clearly be grouped based on the geographic locations from which they were obtained. G enetic relationships among isolates were very robust. Relationships were de termined using both the 'genetic similarity' method of Nei and Li and the ' genetic distance' method of Skroch. We conclude that both methods are equal ly effective for determining intraspecific genetic relationships when the m ajority of markers are polymorphic.