Genome Level Analysis of Yield Loci in Wheat

The discovery and use of new dwarfing and maturity alleles were major advances in wheat breeding that led to the high yielding varieties of the Green revolution of the 1960s. Over the past decade yield improvement has slowed to about 1% increase per year. Although many quantitative trait loci (QTL) for yield have been identified in wheat, few have been deployed in breeding programmes, partly due to problems in introgressing large region. Genomic resources have tremendously increased in the last years, which help making progress in fine mapping QTL. A multi-environment analysis of a double-haploid population of a cross between two Australian cultivars RAC875 (high yielding under drought) and Kukri (low yielding under drought) enabled the detection of QTL using data from 23 field trials. Target QTL that increases yield and yield components in hot and dry climates, were fine mapped using the cv Chinese Spring reference sequence and whole genome shotgun sequences of Australian parental lines. We identified genomic rearrangement between RAC875 and the reference, and narrowed down the QTL intervals to a list of genes which will be studied for their effect on yield.