Identification of Molecular Marker for Septumless Bold Pod in Brassica campestris

Two cultivars of yellow sarson (Brassica campestris), B9 and NC1 have sharp phenotypic differences: a) pubescent or glabrous leaves, b) septumed pod with less number or septumless bold pod with higher number of seeds, and c) erect or drooping pods relative to stem axis. It is established that septum less pod is related to enhancement of seed yield and also related to high shattering resistance. The character septumed pod and pubescent leaf are controlled by single genes with complete dominance and are situated on the same linkage group, as evidenced by the study of F₁, F₂, F₃ and back cross population. To identify some DNA markers associated with septumless pod, firstly, Restriction Fragment Length Polymorphism (RFLP) between the parents were searched using 30 nonrepetitive clones picked from 89 partial genomic library as probes, secondly, Randomly Amplified Polymorphic DNA (RAPD) analysis was done by using 45 random decamer primers. RFLP analysis produced 182 discrete monomorphic bands i.e., they are unable to differentiate the two parents. In RAPD analysis, six primers produced 15 polymorphic fragments out of total 430 bands amplified by 45 primers. Among them A8-350, A10-250, A10-560 RAPD bands are expected to be linked with septumless bold pod and A3-720 with pub locus as evidenced from the bulked segregant analysis (8SA). These RAPD marker fragments of DNA were subsequently used as RFLP probes. A8-350 used as a probe revealed polymorphic bands in Eco RI digested parental DNA and also showed linkage both with septumless and glabrous loci in BSA. Approximate likelihood estimator of genetic distance between septumless locus and the marker is 1.67 cM as calculated through pooled sample mapping.