Bio-fortification of potato tubers using foliar zinc-fertiliser.

摘要

Worldwide, many people are Zn-deficient. Dietary Zn intake can be increased by producing crops with higher concn. of Zn in their edible portions. This can be achieved by applying Zn-fertilizers to varieties with an increased ability to acquire Zn and to accumulate Zn in their edible portions. Potato is an important food crop and, therefore, a target for biofortification with Zn. Field trials incorporating a core collection of 23 potato genotypes, performed over 4 yr (2006-2009), indicated significant genotypic effects on tuber Zn concn. and suggested that tuber Zn concn. was influenced by environmental effects, but also that genotype x environment interactions were not significant. Tuber Zn concn. averaged 10.8 mg kg--1 DM, and the ratio between the lowest and highest varietal tuber Zn-concn. averaged 1.76. Tuber Zn concn. could be increased by foliar Zn-fertilization. Tuber yields of Maris Piper were unaffected by foliar applications of <1.08 g Zn plant--1. Relationship between tuber Zn concn. and foliar Zn application followed a saturation curve, reaching a max. at approx. 30 mg Zn kg--1 DM at a foliar Zn application rate of 1.08 g plant--1. Despite a 40-fold increase in shoot Zn concn. compared to unfertilized controls following foliar Zn-fertilization with 2.16 g Zn plant--1, only a doubling in tuber Zn concn. was observed. This suggested that the biofortification of tubers with Zn was restricted by the limited mobility of Zn in the phloem. A significant positive linear relationship between tuber Zn concn. and tuber N concn. supported the hypothesis of co-transport of Zn and N-compounds in the phloem.