Induced mutations in plant breeding

Abstract

Many important traits for plant domestication and improvement have resulted from human selection for novel alleles of structural or regulatory genes. In addition to naturally-occurring genetic mutations, novel alleles have been induced in plants by chemical and physical mutagenesis. The goal of mutagenesis is to induce genetic variation in cells that give rise to plants, while minimizing chimeras, sterility and lethality. For several crop species, chemically-mutagenized populations of a few thousand lines were sufficient for finding the desired phenotype. The efficiency of mutation breeding can be improved by screening plants at the genetic level, prior to phenotypic analysis. High-throughput physical methods and, increasingly, next-generation sequencing are being used to identify lines with induced mutations in candidate genes. An alternative approach to increasing the precision of mutation breeding is through gene-specific mutation using engineered nucleases. Allelic diversity in candidate genes, whether induced naturally or experimentally, can be a resource in breeding programs for developing new agricultural traits.