Morphological and molecular characterization of Brassica rapa ssp yellow sarson mutants

Abstract

Thirteen out of 55 gamma-rays induced promising mutants of Brassica rapa ssp yellow sarson along with
their two parents namely, NDYS-2 (V1) and YST- 151 (V2) were investigated with a view to characterize
the genetic variability through morphological as well as ISSR markers analysis. Mutants showed wide range
of variability for seed yield, yield attributes, oil content (%) and Alternaria blight disease reaction. Five
mutants, namely, V1M5, V1M20, V1M42, V1M43 and V1M54 showed significantly high seed yield and high
oil content as well as improved level of tolerance to Alternaria blight as compared to parents.
Investigation using ISSR analysis showed high degree of variation yielding 78 bands scored for the presence
or absence of bands among genotypes. Three out of 13 oligonucleotide primers gave reproducible DNA
bands suitable for establishment of genetic diversity. Genetic similarity ranging from 0.54 to 0.91 using UPGMA
cluster analysis based on ISSR bands was noticed. The mutants were put into three major clusters; cluster II
was represented by three sub-clusters IIAa, IIAb and IIB. The present investigation clearly indicated that
morphological traits alone could not be considered as the true reflection of their genotypic characteristics and
hence the need of molecular analysis using ISSR markers is proved.