AMPLIFIED FRAGMENT LENGTH POLYMORPHISM (AFLP) IN SOYBEAN - SPECIES-DIVERSITY, INHERITANCE, AND NEAR-ISOGENIC LINE ANALYSIS

Amplified fragment length polymorphism (AFLP) analysis is a PCR-based technique capable of detecting more than 50 independent loci in a sing le PCR reaction. The objectives of the present study were to: (1) asse ss the extent of AFLP variation in cultivated (Gycine inax L. Merr.) a nd wild soybean (G. soja Siebold & Zucc.), (2) determine genetic relat ionships among soybean accessions using AFLP data, and (3) evaluate th e usefulness of AFLPs as genetic markers. Fifteen AFLP primer pairs de tected a total of 759 AFLP fragments in a sample of 23 accessions of w ild and cultivated soybean, with an average of 51 fragments produced p er primer pair per accession. Two-hundred and seventy four fragments ( 36% of the total observed) were polymorphic, among which 127 (17%) wer e polymorphic in G. max and 237 (31%) were polymorphic in G. soja. F-2 segregation analysis of six AFLP fragments indicated that they segreg ate as stable Mendelian loci. The number of polymorphic loci detected per AFLP primer pair in a sample of 23 accessions ranged from 9 to 27. The AFLP phenotypic diversity values were greater in wild than in cul tivated soybean. Cluster and principal component analyses using AFLP d ata clearly separated G. max and G. soja accessions. Within the G. max group, adapted soybean cultivars were tightly clustered, illustrating the relatively low genetic diversity present in cultivated soybean. A FLP analysis of four soybean near-isogenic lines (NILs) identified thr ee AFLP markers putatively linked to a virus resistance gene from two sources. The capacity of AFLP analysis to detect thousands of independ ent genetic loci with minimal cost and time requirements makes them an ideal marker for a wide array of genetic investigations.