Identifying radiation induced mutations in commercial low seed Murcott mandarins.

Abstract

Murcott and Afourer mandarin varieties are anticipated to drive future expansion of the mandarin export industry in Australia. The Department of Agriculture and Fisheries and commercial citrus growers have previously secured plant breeders rights for the propagation of low seed Murcott varieties generated via radiation mutagenesis. In this investigation, we sought to identify radiation induced mutations within three low seed Murcott varieties (IrM1, IrM2 and Phoenix) that could be used to effectively differentiate each cultivar. In the course of this investigation, we developed improved methods for isolating high quality citrus DNA up to 130 kb in size. We also gained expertise in the use of cutting-edge portable DNA sequencers which have broad utility in a range of diagnostic applications. Our investigations led to the development of useful software for processing long-read sequencing data and generated significant amounts of genomic information for the economically important Murcott variety. Future investigations will focus on optimising genome assembly algorithms and generating effective pipelines for identifying mutations within both long and short-read sequencing data. Ultimately, our aim is to develop molecular tests that can accurately identify low seed Murcott cultivars for variety protection purposes. Information gained from the investigation may also allow for the elucidation of genetic mechanisms underlying the low seed phenotype.