Application of Soft X-ray and Near-Infrared Reflectance Spectroscopy for Rapid Phenotyping of Mutant Rice Seed

摘要

Rice is a major food staple for over half of the world's population. Its production is limited by biotic and abiotic stresses. Mutant populations have become indispensable as a source of genetic variation for breeding and gene function studies. Fast and accurate "omics" methods for mutant identification and trait screening enable better use of mutant populations. We are in the process of developing and adapting various genomics and phenomics approaches to facilitate mutation breeding and genetics. Here, we describe strategies for utilising Soft X-ray Radiography (SXR) and Near-Infrared Reflectance Spectroscopy (NIRS) for screening mutant seed populations to detect phenotypic outliers. In order to evaluate, adapt and optimise the screening procedures and strategies, we used seed from putative mutant population of japonica rice generated via irradiation with gamma and X-rays. The population was propagated by self-fertilisation for four generations to provide material for both genomic and phenomic studies. Morphological observations were performed throughout propagation as an indicator that heritable trait changes have been produced. Optimisations of non-destructive SXR and NIRS screening methods suggest that these could be successfully applied as a pre-screen in mutation breeding. Such methods are likely to be most valuable in crops where seed quality is a major target for genetic improvement.