Zinc bio-fortification and kernel quality enhancement in elite Basmati rice (Oryza sativa) cultivars of south Asia through legume residue-recycling and zinc fertilization

Abstract

Basmati-rice (Oryza sativa L.) is a geographical indication and most remunerative foreign-exchange earning crop in Indo-Gangetic-plains-region (IGPR). In current study, summer-mungbean residue-recycling (SMB–RR) and Zn-fertilization through zinc-sulfate-heptahydrate (ZSHH) significantly enhanced the grain yield in basmati rice genotypes by 11.8 and 8.4%, respectively over summer-fallow (SF) and control; besides higher hulling and headrice recovery. Kernel-length before and after cooking enhanced by 3.79 and 5.03%, respectively by SMB–RR over SF. SMB–RR and ZSHH registered higher Zn concentration in rice grains (31.4, 32 mg/kg); besides total Zn uptake (1024.5; 1000.8 g/ha) and Zn harvest index (ZHI), indicating ZSHH offers vital solution to curtail Zn malnutrition. Among basmati-rice cultivars, Pusa–2511 exhibited highest grain yield (5.07 t/ha), hulling (70.9%), kernel-breadth before (0.17 cm) and after cooking (0.24 cm), and Zn concentration in grains (32.8 mg/kg); while Pusa 1121 exhibited highest kernel–length before (0.84 cm) and after cooking (1.6 cm), and kernel L: B ratio after cooking (7.85). The ZSHH supplied plots led to respective significant enhancement in ZHI to the tune of 7.69% over control plots. Overall, SMB–RR and Zn-fertilization assume great significance in improving productivity, kernel-quality and Zn bio-availability in basmati-rice cultivars having global repute as top-quality rice.