Genetic systems, recombination and variability

Abstract

This subject is reviewed with reference to (1) sources of variation; (2) manipulation of genetic systems; and (3) control of recombination. The last is exemplified by (a) indirect selection for plant genotypes with high chiasmata frequencies, (b) the production by Riley et al. of the wheat variety Compair, which involved the incorporation of a gene for resistance to Puccinia striiformis from Aegilops comosa into the wheat cv. Chinese Spring after genetic interference with the regulation of meiotic chromosome synapsis (suppression of the Ph locus). Also discussed are the prospects of utilizing allopolyploids and diploids. The impact that new techniques available to plant breeders will have on genetic systems, recombination and variability is discussed