Salum, Kasele2026-03-132026-03-132014https://www.suaire.sua.ac.tz/handle/20.500.14820/7414DissertationCassava Brown Streak Disease (CBSD) is a viral disease that impacts cassava tuberous root quantity and quality by causing a brown, dry, corky necrosis within the starch bearing tissues. Tire efficient way to control this disease is the use of resistant cassava varieties. This study was carried out to genotype the mapping population of Mkombozi x TMS 4(2)1425 and develop a single nucleotide polymorphic (SNP) genetic linkage map. Before SNP genotyping was done, the study to determine the integrity of 325 Fl individuals using ten polymorphic simple sequence repeat (SSR) markers to eliminate unknown parental combinations was done. SSR data revealed 158 true crosses, 135 off- types or admixtures, 31 selfs and one genotype (MT 210) was rejected due to many missing data. SNP genotyping was carried out using a reduced representation genotyping- by-sequencing approach at the University of Berkeley. Genetic linkage analysis was performed using Join Map software, version 4.1, Linkage analysis resulted in a total of 1136 SNP markers spanning 3207.9 cM assigned into 18 linkage groups (LGs) of the integrated linkage map. The average marker spacing of 3.4 cM that ranged from 1.3 cM to 10.1 cM was observed from this population. The total of 802 SNP markers were distributed on 19 LGs of female parent (Mkombozi) spanning 2848 cM with an average marker spacing of 3.7 cM ranging from 1.7 to 6.2 cM. On the male parent (TMS 4(2)1425), 593 SNP markers were distributed on 18 linkage groups spanning 2482.8 cM with average marker spacing of 5.2 cM ranging from 1.9 cM to 12.6 cM. The genetic linkage map developed in this study will be used for the identification of molecular markers and quantitative trait loci (QTLs) associated with CBSD tolerance in Mkombozi. The molecular markers and QTLs identified provide useful materials to breed and select CBSD resistance cassava varieties through marker-assisted selection (MAS).enSingle nucleotide polymorphismCassava brown streak diseaseCassava tuberous root quantityMkombozi x tms 4(2)1425Thesis