Characterisation of genetic variation for aluminium resistance and polyphenol oxidase activity in genebank accessions of spelt wheat

Spelt wheat [Triticum aestivum ssp. spelta (L.) Thell.] is becoming a valuable crop due to its reputation as a healthy food. In Australia, this crop has not been targeted for systematic breeding. Identification of spelt a genotypes having low PPO activity and resistance to acid soils (Al3+) are desirable attributes for future cultivar development. We evaluated 51 genebank accessions of spelts from the Australian Winter Cereals Collection for polyphenol oxidase (PPO) activity and for resistance to aluminium (Al). PPO activity was measured both visually and spectrophotometrically, using L-DOPA substrate. PPO activity for genotypes ranged from 0.15 to 1.3 and could be grouped into 'low', 'medium' and 'high' categories. At least eight accessions exhibited low PPO activity (not different to the durum check cultivar Arrivato). After measuring PPO activity, the same kernels were further evaluated for Al resistance using a nutrient solution culture method with haematoxylin staining test of root tips. Thirty-three accessions were resistant to Al. Functional gene markers associated with loci conditioning Al resistance gene (TaALMT1]) and PPO activity (XPPO-2A) in common wheat confirmed their association with target phenotypes within spelt accessions. Genetic variation within spelt wheat for important agronomic and quality traits such as Al resistance and PPO suggested that progress in spell improvement can be made by molecular plant breeding. Diversity Array Technology (DArT) based allelic data revealed that these spelt accessions are genetically diverse.