Influence of genotype and harvesting age on the mineral dynamics of Brassica oleracea var. acephala cultivated in South Africa

Abstract

The concentration of desirable minerals in vegetables could influence consumers’ preference for certain vegetable species especially in the recent times in South Africa where packaged vegetables are increasingly labelled with the details of their mineral constituents. The agronomic practices and the genotypes used by farmers could therefore influence the quality of their products. Six genotypes of Brassica oleracea var. acephala were cultivated in the Research and Experimental Farm of the University of Zululand, South Africa, to determine the influence of harvest age on the mineral dynamics of the vegetable types. The results of this study indicated that harvesting of B. oleracea fifteen weeks after transplanting could help to capture the highest levels of nutrient concentrations. Analysis of the comparative performance of the six genotypes tested in the study also suggests that genotype 2 showed superior performance in terms of nutrient accumulation. However, an improvement programme via hybridization of genotypes 2 and 3 could help increase the level of zinc to balance iron-to- zinc ratio in both genotypes. Intraspecific hybridization programme that aims to breed for zinc improvement on genotype 2 could also be of advantage in a situation where food based strategy is the main target to addressing iron and zinc deficiencies especially among financially challenged population groups. The current study is the first literature on the mineral dynamics among genotypes of B. oleracea var. acephala in northern KwaZulu-Natal, South Africa