Wheat, barley and oat are major cereal crops that account for most of the food directly consumed by humans. We use wild relatives and elite cultivars of these crops to increase genetic variability, analyze the genetic/molecular basis of host resistance, and incorporate new traits to improve on existing germ plasm. In addition to meiotic recombination, we use radiation induced chromosomal breaks to map and clone genes present on various chromosomes and or genomes. Moreover, we analyze the cytoplasmic genomes (those present in the mitochondria and chloroplast) and their contribution to improving biotic and abiotic stress tolerance in plants. We have accumulated a large collection of wheat alloplasmic lines (lines carrying alien cytoplasm) that are being characterized for their effect on disease resistance, abiotic stress tolerance, plant growth, vigor and other developmental traits at the genomics level.