A Century of Cytogenetic and Genome Analysis: Impact on Wheat Crop Improvement

Abstract

Beginning in the first decade of 1900, pioneering research in disease resistance and seed color inheritance established the scientific basis of Mendelian inheritance in wheat breeding. A series of breakthroughs in chromosome and genome analysis beginning in the 1920s and continuing into the twenty-first century have impacted wheat improvement. The application of meiotic chromosome pairing in the 1920s and plasmon analysis in the 1950s elucidated phylogeny of the Triticum-Aegilops complex of species and defined the wheat gene pools. The aneuploid stocks in the 1950s opened floodgates for chromosome and arm mapping of first phenotypic and later protein and DNA probes. The aneuploid stocks, coupled with advances in chromosome banding and in situ hybridization in the 1970s, allowed precise chromosome engineering of traits in wide hybrids. The deletion stocks in the 1990s were pivotal in mapping expressed genes to specific chromosome bins revealing structural and functional differentiation of chromosomes along their length and facilitating map-based cloning of genes. Advances in whole-genome sequencing, chromosome genomics, RH mapping and functional tools led to the assembly of reference sequence of Chinese Spring and multiple wheat genomes. Chromosome and genomic analysis must be integrated into wheat breeding and wide-hybridizaton pipeline for sustainable crop improvement.