Sorghum breeding for biotic stress tolerance

Authors: PERUMAL, RAMASAMY - Kansas State University; MAGILL, CLINT - Texas A&M University; PETERSON, GARY - Texas A&M Agrilife; Prom, Louis; BASHIR, ELFADIL - Kansas State University; TESSO, TESFAYE - Kansas State University; SERBA, DESALEGN - Kansas State University; LITTLE, CHRISTOPHER - Kansas State University

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 10/6/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Sorghum cultivars react differently when exposed to diseases and insect infestation. As a result, breeding sorghum for resistance to diseases and insects is a long-term process which involves the identification of resistant sources, incorporating of single or many genes into high yielding varieties. The topics in this chapter examine the use of classical and molecular methods in resistance breeding for major diseases such as anthracnose, head smut, stalk rot, rust, ergot, grain mold, downy mildew, bacteria, viruses and the parasitic witchweed striga along with damage caused by major insects (midge, shoot fly, stem borer, green bug and sugarcane aphids) and nematodes. Thus, sorghum breeders and researchers can gain an insight as to the use of both classical and modern molecular technologies to shorten the time required to breed for resistant cultivars.

Technical Abstract: Varietal differences among sorghum cultivars in response to pathogens and insects have been reported for over 100 years. As in other crops, these differences have led to continual efforts to discover and incorporate genes for resistance into high yielding, high quality cultivars. Whether dealing with a single gene or polygenic trait, resistance breeding is a long-term project and due to changes in the antagonists, requires continuous effort. Sorghum breeding, as is true for other crops, is poised to take advantage of remarkable advances in genomics and molecular technologies. Thus, while classical breeding methods have been successful in identifying and incorporating resistance to biotic stresses, the emphasis of this chapter is to feature examples that will support the use of tools and technology that can now be used to inform, simplify and accelerate breeding of improved sorghums. In the prospect that the genes involved will be of use with rapidly developing technologies for gene editing and gene transfer, a special effort of this chapter is to document many of the previously discovered sources of resistance. Lack of known resistance genes is also included, as is information on the shared motifs and function of the vast majority of resistance to "R" genes that have been identified thus far. To make it succinct, this chapter deals with recent classical and molecular development with regard to sorghum major biotic stresses which include diseases caused by major fungi (anthracnose, head smut, stalk rot, rust, ergot and grain mold) and an oomycte (downy mildew), bacteria, viruses and the parasitic witchweed striga along with damage caused by major insects (midge, shoot fly, stem borer, green bug and sugarcane aphids) and nematodes.