ABSTRACT
Rice is prone to high arsenic (As) accumulation under reduced paddy soil conditions which depends on genotypic variation, although it is poorly understood for Pakistan's scenario. This study aimed to distinguish As-safe (tolerant) genotypes from those which are As-unsafe (accumulating) in a pot experiment utilizing twenty different genotypes. Arsenic in soil (25 mg/kg) showed a significant effect on plant morphological parameters (number of tillers, plant height, root and shoot dry weights, number of spikelets, grain dry weight). Under As stress, Shaheen Basmati resulted in maximum number of tillers (8/pot) while Bas-370 has the minimum number of tillers (3/pot); Bas-2000 produced maximum shoot dry weight (2.5 g/pot) and Kainat genotype showed minimum shoot dry weight (0.12 g/pot). Total As concentration in root and shoot of fine varieties IR-6 and KSK-282 were (44 and 22 mg/kg DW) higher than that of coarse genotypes (3 and 2 mg/kg DW). Grain As concentration was found to be the lowest in IR-36, Noor Basmati, Shaheen Basmati and PB-95 (0.08, 0.10, 0.18, and 0.16 mg/kg DW). This study highlights that IR-36, Noor Basmati, Shaheen Basmati and PB-95 genotypes has grain As concentration below the FAO/WHO safe limit of As in rice grain (0.2 mg/kg DW) and should be considered for safe rice consumption and minimize As exposure to humans via rice consumption.
