ANALYSIS OF GENETIC VARIATION IN WORLD COLLECTION OF DURUM WHEAT (TRITICUM DURUM) USING MORPHOLOGICAL, DNA AND SEED STORAGE PROTEIN MARKERS

Abstract

Durum wheat (Triticum durum L.) is an allotetraploid crop species with relatively low gluten content, commonly used in the preparation of pasta, couscous, noodles, macaroni, and flatbreads. The present study was designed to assess the extent of genetic diversity in a global collection of durum wheat accessions grown under the climatic conditions of Pakistan, using morphological traits, protein profiles, and DNA-based markers. A total of 175 accessions were cultivated for two successive years in separate fields of the Azad Kashmir region. Although molecular analysis was conducted only on a representative subset of 30 accessions, it provided useful but preliminary insights into genetic diversity. Future studies with larger datasets are needed to strengthen these results. Analysis of variance revealed highly significant F-values for both genotypes and genotype × year interactions across 18 morphological traits. Seed storage proteins of the genotypes were profiled through SDS-PAGE, which yielded 719 scorable bands from 161 accessions, average of 4.5 distinct protein bands per genotype, each considered as an allelic variant. Considerable variation in genetic distance (GD = 0–100%) was observed; 27 comparisons showed complete homozygosity (GD = 0%), while 252 comparisons exhibited full dissimilarity (GD = 100%) at protein loci. For molecular analysis, 30 randomly selected genotypes were evaluated with 40 RAPD and 50 SSR primer sets. RAPD markers produced 92.05% polymorphism, with genetic distances ranging from 0.00 to 32%. Cluster analysis grouped the 30 genotypes into two main clusters. Similarly, SSR primers were mostly polymorphic, generating 174 fragments in total, with an average of 3.44 bands per primer and 2–7 bands per locus. Genetic distance based on SSR data ranged between 2% and 38%, and cluster analysis again separated the genotypes into two major groups.