High temperature effect at terminal stage in mustard genotypes

Twenty two promising mustard (Brassica juncea (L.) Czern & Coss) genotypes were sown in October and November of rabi 2005–06. Late sowing was done to allow high temperature exposure on mustard genotypes at seed development stage. Late sowing at terminal stage caused significant and drastic reduction in number of branches, number of siliquae, seed yield, harvest index and test weight. Maximum reduction in dry matter production at 50% flowering (64.3%), at harvest (73.7%) and in seed yield (90.3%) on secondary branches occurred in RGN-48 while number of siliquae on secondary branches in Kranti (77.7%) over normal sown plants. Significant genotypic variations were also observed for these characters. Genotypes PCR-7, SKM-9927, SKM-9928 and NPJ-93 were found tolerant to high temperature at terminal stage as these showed value of heat susceptibility index ≤ 0.5 and yield stability ratio > 70.0%. Dry matter accumulation at harvest (r=0.836) showed positive association with seed yield in mustard genotypes under late sown condition.