An experiment was conducted at the research farm of College of Agriculture, Nagpur to
determine the nature and magnitude of genetic variability in F 2 and BC 1 F 1 crosses in terms of
various genetic parameters for the different characters. In rabi 2022 three BC 1 F 1 crosses (TAM
108-1 x PC-6) x TAM 108-1, (Kranti x PC-6) x Kranti and (ACN-9 x PC-6) x ACN-9 done for
transfer of powdery mildew resistance from B. carinata (PC-6 donor) to B. juncea varieties and
their three F 2 crosses of TAM 108-1 x PC-6, ACN-9 x PC-6 and Kranti x PC-6 along with their
four parents ACN-9, TAM 108-1, Kranti and PC-6 , were evaluated in RBD with 3 replications.
The data were recorded on days to first flower, days to maturity, plant height (cm), number of
branches plant -1 , number of siliquae plant -1 , 1000 seed weight (g) and seed yield plant -1 (g), and
statistically analyzed. In many of the F 2 or BC 1 F 1 crosses seed yield plant -1 was less though their
number of siliquae plant -1 which was more due to the involvement of two species i.e., juncea and
carinata. Wide range was observed for all the seven characters studied among the three F 2 crosses
and the three BC 1 F 1 crosses. Moderate to high per cent of GCV and PCV were exhibited for plant
height, number of branches plant -1 , number of siliquae plant -1 , 1000 seed weight and seed yield
plant -1 in all F 2 and BC 1 F 1 crosses. High to moderate heritability coupled with high moderate
genetic advance as per cent of mean was exhibited in all the F 2 and BC 1 F 1 crosses except BC 1 F 1
cross (ACN-9 x PC-6) x ACN-9. Selection of potential material were done in F 2 and BC 1 F 1
generation. In F 2 generation, 29 single plants were identified based on the characters seed yield
plant -1 , number of siliquae plant -1 and number of branches plant -1 for forwarding to F 3 generation
by plant to row method for their exploitation. In BC 1 F 1 crosses 64 single plants selected on the
basis of resistance to powdery mildew less than 3 score were backcrossed with their respective B.
juncea parents to get seeds of BC 2 F 1 which will be forwarded to next generation with an aim to
transfer the genetic constitution of B. juncea to improve its yield level.