Classification for Core Collection of Rapeseed-Mustard (Brassica juncea L.) Germplasm

Based on passport data of maturity (early, medium and late), stratified random sampling procedure was adopted to select 385 accessions of Indian mustard (Brassica juncea L.) maintained at NRCRM, Bharatpur, India, which was taken for this study. Observations of 17 characters were taken into consideration for the classification. All the accessions were classified in 9 clusters. Core collections of different cluster were selected with the help of following method, which is the main objective of the project. Mean ± SD of each character of different clusters were calculated and taken into consideration for selecting the core accessions of each cluster. All the characters in different clusters were studied and the character that has more than Mean ± SD was marked rank first. All the accession that ranked first in a minimum of four characters, were selected as core collection of that group. This way, out of 385 accessions only 116 accessions were selected as core collection, which is 30.13%. Now, it will be easy to maintain and easierfor the breeder to select for breeding purposes. Viewing the Euclidean square distance, different accession of Brassica can be selected for breeding purposes as per the requirements of the breeder.