Efficiency of Some Molecular Markers Linked to Rhizomani; Resistance Gene (Rzd for Marker Assisted Selection in Sugar Beet

摘要

Sugar beet (Beta vulgaris L.) is one of the two major products supplying sugar (sucroses) in the world. Rhizomania is one of the most destructive diseases of sugar beet world-wide. Holly is Ihe major source of resistance to rhizomania. The objectivesof this study were to identify the dominant homozygous genotypes resistant to rhizomania using ZN1 molecular marker, to field evaluate Si progenies of plants already proved to be containing the marker and also to determine the relationship of this and other SCAR (sequence characterized amplified region) markers with SNP1 (single nucleotide polymorphism) marker associated with the Rz> gene. Molecular analysis was carried out on 27 O-type populations (consisting of 13 susceptible and 6 resistant genotypes). Field evaluation and scoring of the phenotypic traits including greenness, growth, uniformity and disease score of 12 O-type populations were carried out on a rhizomania-infested field. The percent agreement of coupling marker ZN1 and repulsion markerZN8 with disease score was 0.91 and 0.93. respectively. Although all O-lypes had the Rz< resistance gene but the phenotypic differences were observed due to the effect of different genetic backgrounds and modifier genes. Overall, the results showed thatthe selected markers can be used for marker-assisted selection (MAS) to reduce the time and cost of breeding programs and increase the efficiency of selection.