Applications of AFLP and ISSR techniques in detecting genetic diversity inthe soybean brown stem rot pathogen Phialophora gregata

AFLP (amplified fragments length polymorphism) and ISSR (inter simple seque nce repeat) analyses were used to detect genetic diversity among 46 Phialop hora gregata isolates including 41 from soybean, four from mung bean, and o ne from adzuki bean. Five AFLP primers amplified 55 fragments, of which 20 bands were polymorphic. Thirteen ISSR primers amplified 66 fragments, of wh ich 45 bands were polymorphic. The ISSR technique detected more polymorphis m than the AFLP technique did. A UPGMA (unweighted pair-group arithmetic me an) dendrogram was constructed based on the 121 amplified fragments with AF LP and ISSR primers to depict genetic diversity and relationships among the 46 isolates. Various levels of DNA polymorphism were detected among P. gre gata isolates from soybean and mung bean. The estimated average genetic div ersity is 0.079 for the population of 45 isolates from soybean and mung bea n. The ISSR technique was shown to be more effective and economic than the AFLP technique in detecting genetic variation in P. gregata.