Genetic diversity among and within CIMMYT wheat landrace accessions investigated with SSRs and implications for plant genetic resources management

fect yield because of reduced lodging. Moreover, a con- siderable LC diversity was found for resistance to pests Many wheat (Triticum aestivum L.) landrace cultivars (LCs) con- such as stem rust (caused by Puccinia graminis Pers.: servedinseedbanksarenotsufficientlycharacterizedtoinspirebreed- based on modified Rogers' distance (MRD), only three Turkish LC accessions formed a distinct cluster in Set 1. The Mexican accessions orthe collectionsofLCsublines. Preliminaryevaluation clustered together with a Spanish accession and a close relationship datawereusuallyrecordedduringthefirstseedmultipli- between a Chilean and Nigerian accession was observed. In Set 2, cation and consisted of observations that were highly gene diversity (He) among the Turkish LCs (0.43) was higher than heritable, easily detectable, and expressed in different among the Mexican LCs (0.35). Analyses of molecular variance environments (DeLacy et al., 2000). However, little in- (AMOVA) revealed considerable genetic diversity within Mexican formation about the genetic variation within LCs and (52.7%) and within Turkish (67.6%) LCs. Pairwise fixation indices associations among LC accessions is available. It is also (FST) were significant, except between two Turkish LCs. Results were still questionable which strategy is the best to ensure discussed in relation to the most suitable collection method of wheat an appropriate maintenance of this variation for future LCs (bulk or individual sublines) as well as to the use of SSRs as a tool for seed bank management. generations.