Pod area index, crop growth rate and intercepted photosynthetically active radiation as influenced by sowing dates in cultivars of Brassica

Among three Brassica cultivars grown for the study, the highest pod area index (PAI) was attained in the first sown crop of Pusa Bold of first crop season with the value being 3.0 and lowest value (1.5) was observed in cultivar Toria-T₉ of the same season. Due to profuse pod habits, the cultivar Pusa Bold recorded highest crop growth rate with values being 34.8, 30.2, 25.8 g/m²/day in the first, second and third sowings, respectively. The cultivars B.O.54 and Pusa Bold with relatively broader leaves intercepted 90 to 96% photosynthetically active radiation (by whole canopy) during siliqua seed filling stages, where as in narrow leaved cv. Toria-T9 it was 74 to 81 per cent. The canopy height measured were 175, 190 and 110 cm in the B.O.54, Pusa Bold and Toria-T9, respectively at the maximum interception period. The maximum photosynthetically active radiation (PAR) interception varied from 41 to 46, 45 to 57 and 37 to 44 per cent at 50 per cent height of canopy in cultivars B.O.54, Pusa Bold and Toria-T9, respectively.