Supplementary potassium application enriched micronutrient status of purple rice (Oryza sativa L.)

Black/purple rice are rich in anthocyanins, antioxidants, vitamins, and fibres, which possess various health benefits including the prevention of cancer, diabetes, and heart diseases. An experiment was conducted to enhance (or modify) the nutrient composition of a Bangladeshi native Purple rice cultivar by potassic (K) fertilizer management. Four fertilizer doses viz., Control (Urea-Triple Superphosphate-Muriate of Potash(MoP)-Gypsum @ 150-52.2-82.5-60 kg/ha, respectively), 20% less urea than the control, 20% additional urea+25% additional MoP than the control, and 25% additional MoP than the control, were used as experimental treatments. Four rice cultivars, viz. BRRI dhan71, Purple dhan, Binadhan-7 and Pahari dhan were used as experimental materials. Brown rice (or hulled rice) of the Purple rice cultivar is rich in protein and minerals compared to test cultivars. The grain yield and mineral content of Purple dhan did not improve significantly by K fertilizer, alone or with additional N, except Fe and Zn. The highest amount of Fe and Zn (105.83 and 47.75 ppm, respectively) was obtained with 25% additional K indicating the scope of bio-fortification through cultural practices. Purple dhan could be used as a potential parental source or donor for further micronutrient enriched rice breeding programmes,which might be used as a weapon for combating micronutrient deficiency in Bangladesh and the world.