Documentation of parents and hybrids tolerant to terminal heat stress in Brassica juncea L.

Fluctuations in temperature during the growth period can damage the inter-molecular interactions needed for proper growth, thus impairing plant development and fruit set, which leads to significant yield loss with greater risks for future global food availability, food accessibility, food utilization and food systems stability. Keeping these in mind present investigation was done to identify of parents and hybrids for terminal heat tolerance.

Nine lines and three testers were crossed in line × tester fashion to develop hybrids. F₁s were evaluated under timely and late sown conditions to study the effect of terminal heat stress by calculating, heat susceptibility index (HSI), heat tolerance efficiency (HTE) and stress tolerance index (STI) on yield and yield traits and to characterize parents and crosses on the basis of their relative tolerance against heat stress at the Agriculture Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during Rabi 2017-18 and 2018-19.

Observations were made for different yield and yield related traits. Genotypes such as BPR 541-4 was found to be tolerant to heat stress at terminal stage and crosses such as Vardan × PM 30, Kranti × RH 406 and Kranti × Urvashi were found to be tolerant to heat stress for seed yield per plant at terminal stage during 2017-18 and 2018-19. Genotypes and crosses that were found to have minimum reduction in seed yield manifested tolerance to heat stress in terminal stage (had lowest HSI, Highest HTE and Highest STI).