Assessment of Mustard Genotypes for Thermo Tolerance at Seed Development Stage

In the present study thirty six mustard (Brassica juncea (L.) Czern & Coss) genotypes were assessed for thermotolerance at seed development stage. Seeds were sown in October (normal sowing) and November (late sowing) of rabi 2007–08. November sowing caused significant reduction in plant height, dry matter accumulation, branching behaviour, harvest index, yield and yield attributes. Delay one month in sowing of mustard leads to the loss of 40.6% in seed yield over normal sowing. Genotypes BPR-541-4, NPJ-112, RGN-145 and RH-0119 were identified thermotolerant at terminal stage as these showed minimum (< 20%) reduction in the number of branches, siliquae number, dry matter at post flowering, seed yield and produced bold seeds. Heat susceptibility index values were ≤ 0.5 and yield stability ratio was > 80.0%. Number of branches per plant (r=0.946) and number of siliquae per plant (r=0.982) showed positive correlation with seed yield in November sown crop.