AFLP-BASED GENETIC DIVERSITY ASSESSMENT AMONG WHEAT CULTIVARS FROM THE PACIFIC-NORTHWEST

Assessing genetic diversity among adapted, elite germplasm may expedit e crop improvement. The objectives of this study were to (i) assess ge netic diversity among a representative sample of spring and winter whe at (Triticum aestivum L,) cultivars adapted to dryland production in t he Pacific Northwest by amplified fragment length polymorphisms (AFLPs ), and (ii) compare genetic diversity estimates (GDEs) generated by me thylation sensitive and methylation insensitive restriction enzymes fo r AFLP analyses, Fifty-four cultivars and two diploid relatives were i ncluded in the study. Sixteen AFLP primer pairs detected 229 polymorph ic bands. Mean GDEs (0.51 and 0.58, respectively) detected by PstI:Mse I (methylation sensitive) and EcoRI:MseI (methylation insensitive) AFL P analyses were significantly different (P < 0.0001), indicating great er diversity was detected for methylated sequences. Mean GDEs, based o n data from both restriction enzyme combinations, were highest (0.58) for spring vs. winter type pairwise comparisons, intermediate (0.53) w ithin winter type, and lowest (0.49) within spring type. Cluster analy sis, ordination analysis, and the analysis of molecular variance sugge sted genetic diversity among cultivars was hierarchically arranged as cultivars nested within market class, and market classes nested within growth habit. AFLP analysis is an efficient technology for assessing genetic diversity among wheat cultivars.