Response of Tissue Zinc to Zinc Fertilisation by Zinc Biofortifier Bush Bean Genotypes Targeted for Low Income Communities

Abstract

Aim: This study investigated the influence of applied zinc on the richness and distribution of Zn in the leaves and grain of Zn dense bean genotypes. Study Design: Treatments of this study were laid out in a completely randomised design (CRD), three replications, repeated three times. Place and Duration: The study was conducted at National Crops Resources Research Institute (NaCRRI), in Uganda during 2011-2012. Methodology: Two Zn biofortifier bush bean genotypes (KaboF6-2.8-27 and NUA69) and Zn rates of 0, 5, 7.5 and 12.5 mg pot-1 were considered in this study. Soil used was an Oxisol obtained from continuously cultivated bean producing soils. Data collected included leaf and grain Zn and estimations of the quantities of these bean consumable parts required to meet the thresh hold daily dietary requirements for pregnant and breast feeding mothers. Results: There was a significant (p<0.05) interaction between Zn rates and genotypes in terms of tissue Zn. Zinc application caused a slight effect on leaf zinc in KaboF2.8-27, but had no significant effect (p>0.05) in NUA69 genotype. Both genotypes maintained a similar response pattern with respect to leaf Zn. Kabo6F2.8-27 was superior and had the highest leaf Zn at 44.3 mg pot-1. As for the grain, KaboF2.8-27 and NUA69 peaked with 43 and 35.9 mg Zn kg-1 both within the application rate of 7.5 mg pot-1. Conclusion: The quantity of leaves required by pregnant mothers to meet their daily dietary Zn requirements is 248 g; while that of breast feeding mothers is 271 g of KaboF2.8-27 genotype. There is need for evaluation of the status of bioavailability of plant tissue Zn in order to ensure its effective and efficient utilisation by communities.