A field experiment was conducted during 1999-2002 at Bawal, Haryana, to study comparative performance of tetralocular Indian mustard [Brassica juncea (L) Czernj. & Cosson] variety 'RB 9901' in comparison with bilocular traditional cultivars 'RH 30' and 'Laxmi' under different planting times and crop geometries in light-textured irrigated soils of semi-arid climate. Crop planted on 14 and 21 October took significantly more days to 50% flowering (55 and 57) and maturity (154 and 156) compared to 7 October planting. The maximum seed yield (2.98 tonnes/ha) and yield-contributing parameters (branches/plant, siliquae on main shoot and siliquae/plant) were recorded when the crop was planted on 21 October and increased the seed yield by 8.5 and 3.5% over that planted on 7 and 14 October respectively. Overall, 'RB 9901' was found superior for seed yield (3.05 tonnes/ha), oil yield (1.26 tonnes/ha) and yield attributes, viz siliquae on main shoot (83), siliquae/plant (026) and seeds/siliqua (19), and outyielded 'RH 30' and 'Laxmi' by a margin of 14.3 and 5.2% respectively. The crop geometry of 45 cm x 10 cm was found optimum for all the varieties. The interaction effects revealed that performance of 'RH 30' was significantly superior when planted on 21 October, whereas 'Laxmi' and 'RB 9901' were equally better under both the sowing dates of 14 and 21 October.
