Molecular characterization of genetic variation in somaclones of durum wheat (Triticum durum Desf) using SSR markers

Abstract

This study is a continuation of a previous work; the main objective is to characterize the induced somaclonal variation in the first generation of durum wheat plants. In a previous experiment, in vitro plants of three genotypes of durum wheat were obtained following treatment with PEG6000 (0%, 10% and 20%). First generation offspring was produced. Five microsatellite markers were used for genotyping 26 durum wheat somaclones obtained under stressful and non-stressful conditions from 3 durum wheat cultivars. Amplifiable and reproducible alleles were obtained in three of the tested loci. These loci provided in total 78 monomorphic alleles of which 69 were detected in somaclones while the remaining 9 in the mother plants. High values of among-population genetic diversity were found, which accounted for 71 % of the total genetic variation. The number of alleles per locus varied from three to six. Estimated genetic distances varied from 0.83 to 1.67 between populations. The somaclonal variation was identified with 2 SSR markers. Five new alleles were identified in somaclonal variants DKR1-S1, DKR1-S2, OZR1-S2, WR1-C3 and WR1-S1at loci gmw131 and gwm427. Genetic variation rate was 21.74%. Eighty % of the genetic variation was identified in plants obtained from callus undergoing high osmotic pressure. The presence of selective agent in the medium could explain the observed genetic variations. Somaclonal variation cannot always be detected at the gross morphological level. The selected SSR markers could be used to study the uniformity of plants obtained from tissue culture and varietal identification.