Genetic mapping of root traits in Lolium perenne

This work aims to identify markers/candidate genes linked with root morphological traits in perennial ryegrass. Identification of such markers/candidate genes will help develop future ryegrass varieties with efficient root systems. Improved root system is useful to plants not only in providing a superior anchorage but resistance to abiotic stresses such as to drought and flooding. To pursue such objectives, an F1 mapping population has been developed by crossing a genotype from the best performing IBERS perennial ryegrass variety (AberMagic) with a genotype from an old un-adapted variety (Aurora). A genetic linkage map of this population has been created with 3775 SNP markers. Highly significant differences in root number, thickness and in other root morphological traits were observed both in the parental genotypes of the mapping family as well as in the progeny of the mapping family. Analysis of root morphological data together with the SNP genotypic data in the progeny has identified a number of genomic regions associated with various root traits. Some regions of the genome harboured SNPs associated with with more than one root traits. Incidentally, traits such as root thickness, root numbers and root depth that showed significant phenotypic correlations of varying degrees had some QTLs in common. The basis of correlations observed will be discussed in the presentation. The presentation will also cover the candidate genes underlying the root morphological QTLs and their possible causal roles in determining the root phenotypes. Significance of the findings of the project in breeding improved root system in Lolium perenne will be discussed.