Effect of interspecific hybridization, geographic origin and distribution on light interception, canopy temperature and seed yield of irrigated oilseed Brassica

Fifteen genotypes of Brassica nopus and eleven genotypes of Brassiea carinata, representing temperate and semi-arid tropical regions respectively, were grown on sandy loam soil under irrigated conditions. Coefficient of intercepted photosynthetically active radiation (IPAR: 400-700 nm), canopy temperature (Tc) and canopy minus air temperature (Tc-Ta) were recorded at mid-day (1200-1400 h) during pod formation stage. B. napus genotypes generally showed significant lower values of IPAR, Tc-Ta and higher Tc than B. carinata genotypes. In both spp., Tc was negatively correlated with IPAR and absolute values of Tc-Ta. Seed yield showed significant negative linear association with Tc and positive significant linear correlations with IPAR and absolute values of Tc-Ta. These associations were, however, expressed only by different regression equations in each spp., indicating that the two amphidiploids were inherently different from each other Tc. or Tc-Ta were observed with an Infrared thermometer faster than IPAR and thus the former techniques could effectively be used for screening the irrigated Brassica genotypes for seed yields.