Mapping of chromosome regions associated with increased vegetative zinc accumulation using a barley doubled haploid population

Abstract

Little information exists regarding the genetics of zinc uptake/accumulation in barley (Hordeum vulgare L.) yet zinc deficiency remains one of the most widespread global nutrient problems. A doubled haploid (DH) barley population, derived from a cross between the Australian cultivar Clipper (low zinc accumulator) and an Algerian landrace Sahara 3771 (high zinc accumulator), was used to map the chromosomal region associated with shoot zinc concentration and content at the early vegetative stage of growth. 150 DH lines and their parents were grown in a calcareous sand supplied with a full nutrient mix under controlled conditions. Shoot zinc measurements of the DH lines ranged from 36 mg/kg to 86 mg/kg for zinc concentration and from 5.3 µg/plant to 15 µg/plant for zinc content. RFLP marker analysis identified a region on the long arm of chromosome 4H as being associated with both these characters. This result shows promise for the use of molecular markers in breeding for increased zinc accumulation in barley.

Introduction

In the past, many agronomically and economically important traits have been mapped in barley. While significant effort has been directed at disease resistance and quality parameters, there has been little research on mapping nutritional characteristics, either at the vegetative or reproductive stage with a consequent lack of knowledge regarding the genetics of micronutrient uptake and transport. With the ever increasing number of linkage maps being produced by various research groups, it is anticipated that mapping of nutritional characters will become more common. The purpose of the study described in this chapter was to identify major genes or QTLs controlling zinc concentration and content in barley shoots at the vegetative stage of development. As well as providing basic information about the process involved in zinc accumulation, this will also provide the starting point for development of molecular markers to assist breeding programs in efficient selection of high zinc accumulating genotypes. Such genotypes are likely to be more resistant to pathogenic attack (Huber and Graham, 1999) and possibly able to transport more zinc to the grain.